- 1 - Document AVC-0, Version 5 ITU Telecommunication Standardization Sector Document AVC-0 Study Group 15 Version 6 Experts Group for Video Coding and Systems July 10, 1996 in ATM and Other Network Environments Source: RAPPORTEUR (Sakae OKUBO) Title: LIST OF AVC DOCUMENTS Purpose: Information Documents for the first meeting of the Experts Group Normal Documents AVC-1 ADDRESS OF COORDINATING MEMBERS AND LIAISON REPRESENTATIVES (SECRETARIAT) AVC-2 EXCERPT OF THE WPXV/1 MEETING REPORT - JULY 1990 (CHAIRMAN) Establishment of the Experts Group for ATM Video Coding was decided at the July 1990 meeting of Study Group XV. Terms of reference of this group, membership and working method, work plan, chairmanship, and liaison statements to relevant standardization bodies are described. AVC-3 PHASE-2 WORK OF MPEG (CHAIRMAN) MPEG has initiated its second phase work for "coding of moving pictures for DSM having a throughput of up to 10 Mbit/s". This document presents MPEG organization, its terms of reference, work schedule highlighting the subjective test in July 1991, and requirements for the second phase work. AVC-4 IMPACT OF ATM NETWORKS ON VIDEO CODING (AUSTRALIA) Major characteristics of ATM-based B-ISDN and their impacts on video coding are identified as follows; - Variable rate video coding which provides better picture quality/rate trade-off and less end-to-end delay. - Cell loss, which may lead to the use of layered coding and cell priority assignment. - Service integration because of service independent nature of the network, which requires a common video coding method; "universal video coding". - Network flexibility requiring an appropriate method of handling multimedia or multichannel connections. As a conclusion, consistency of the target video coding scheme with the direction of B-ISDN standards is emphasized. AVC-5 UNIVERSAL VIDEO CODING FOR ATM NETWORKS (AUSTRALIA) A Universal Video Coding approach, which is based on a hierarchical, layered coding with different sets of layers corresponding to different service classes, is proposed for integration of video signal representation and coding. The following study items are identified; - Practicality of the scheme: range of parameters defining the service classes and appropriate hierarchies. - Optimum coding of each layer. - Cost/complexity trade-off. - Incorporation of or migration form existing coding schemes. - Flexibility to accommodate future improvements of the algorithm. - Accommodation of still image coding. It is proposed that the group should investigate the practicality of the Universal Coding approach and further develop the concept as a target architecture of the ATM video coding. AVC-6 SIGNALLING FOR AUDIOVISUAL OR MULTIMEDIA CONNECTION ON ATM NETWORKS (AUSTRALIA) It is pointed out that studies on network and end-to-end signalling appropriate for multiplexing of audio, video, and data are required in the light of virtual channel based connections in ATM networks. Error protection mechanism and encryption aspects are also touched upon. AVC-7 JAPANESE ACTIVITIES ON ATM VIDEO CODING STANDARDS (JAPAN) "AV&ATM Video Coding Subcommittee" is introduced as a national experts group in Japan which works tied up with the CCITT's Experts Group. AVC-8 CONSIDERATION ABOUT ATM CODING APPLICATIONS AND FEATURES (JAPAN) To facilitate setting objectives of the ATM video coding standard, possible applications and technical requirements to be met are listed up as a summary matrix. Technical requirements are presented in terms of resolution, picture quality and delay. It is stressed that the new standard should cover higher resolution and quality up to the HDTV level. AVC-9 CONNECTIVITY WITH CURRENT SYSTEM AND RECOMMENDATION SCHEDULE (JAPAN) As to the connectivity, the opinion is summarized as follows; - To keep compatibility of ATM video coding with the existing standard is preferable. - For low bit rate STM networks, the "terminal level" connectivity is indispensable. - For high bit rate ATM networks, H.261 may be modified to some extent. The extent of modification is to be studied. As to the schedule toward recommending an ATM video coding standard, it is suggested to make an outline recommendation in 1992 and a final one until 1994. AVC-10 TECHNICAL PROBLEMS AND PROCEDURES (JAPAN) Technical problems are picked up which should be worked out or clarified by the Group. Among them, "requirements for network characteristics" is recognized as the most urgent taking into account the SGXVIII activities. For the group's working method, step by step one based on a reference model with verification by hardware is proposed. This document also provides information on activities of participating organizations. AVC-11 ATM ADAPTATION LAYER - AAL (JAPAN) The aim of this document is to clarify the AAL problems, particularly from multimedia multiplex point of view. Taking AAL Type 2/I.363 as a basis, discussion points for each of the AAL elements (SN, IT, LI and CRC) are described. As a conclusion, it is stressed that a framework for multimedia multiplex in ATM environments should be established at the earliest stage. AVC-12 VIDEO CODING ACTIVITIES IN CMTT (LIAISON REPRESENTATIVE FOR CMTT) The organization of CMTT is presented which has Working Party CMTT/B and Task Groups CMTT/2 and CMTT/3 having close relation to the activity of this Experts Group. CMTT's activities on contribution, HDTV digital transmission and secondary distribution are briefed. Considering that CCITT's Experts Group and MPEG are looking into generic video coding for television signal transmission and storage, close collaboration is emphasized to avoid work duplication and different standards for the same application. AVC-13 COMPENDIUM ATM - CODING PROCEDURES (NETHERLANDS,GERMANY, UNITED KINGDOM, FRANCE, NORWAY, SWEDEN, PORTUGAL, ITALY, SPAIN, BELGIUM) Results of the extensive study which has been carried out in the COST 211 project are reported. The following topics are covered; - Terminology - Coding models - The H.261 capabilities for ATM - Impact of QOS and preventive policing on coding performance - Bit rate versus quality - Guidelines for simulation - Guidelines for hardware experiments. AVC-14 INTERCONNECTIVITY OF FUTURE AV-SYSTEMS (THE ROYAL NETHERLANDS PTT, PTT CONTEST) Necessity of interworking among existing and future audiovisual systems are discussed from different point of view; technical achievements, applications, standardization and implication of marketing. It is stressed that we should bear in mind the users request and achieve the highest level of compatibility. Analysis of interconnections is tried from several angles; analog connection, digital CCIR 601 connection, digital connection with simple transcoding, and direct digital connection. AVC-15 ATM VIDEO CODING (AT&T, DIS, DAVID SARNOFF LABS, PICTURETEL, APPLE COMPUTER) US views are presented to various aspects of the work to be done by the Experts Group; - Major effort is needed for performance analysis of ATM video coding systems in terms of coding efficiency and network requirements to clarify the constant quality/variable bit rate concept. - Efforts should be made to define work areas and their priorities by considering service, coding, and network aspects. - The primary focus of ATM video coding work should first be shifted toward service applications showing the greatest promise in terms of network utilization. - As to the picture format, CCIR Rec. 601 should provide the next option to CIF for higher bit rate applications. -Applications requiring EDTV or HDTV should be given lower priority pending clarification of related TV standards. - A level of compatibility should exist between the existing and the new coding schemes. - A realistic network model should be developed. - AAL should be considered. - The group should coordinate its activities with SGXVIII. AVC-16 COMMENTS ON "MEMORANDUM OF TOPICS" (BELGIUM, FRANCE, FRG, ITALY, NETHERLANDS, NORWAY, UK) This document summarizes European views concerning the topics and work plan of the new ATM video coding Experts Group. Some of which are listed as follows; - The Group should initially focus on standard TV signals, taking into account extension to higher resolutions. - Less delay than that of the current system should be sought. - Bit rate range: 64 kbit/s to a few tens Mbit/s initially, higher bit rates later. - Compatibility with existing AV Recommendations should strongly influence the decisions of the Group. - The Group should finalize a coding standard in 1994, but produce a framework recommendation in 1992. - A step by step method using Reference Models and hardware trials are supported. - Collaboration with MPEG and CMTT should be as close as possible. AVC-17 OUTSTANDING ISSUES ON LOW BIT RATE VIDEO CODING FOR ATM NETWORKS (BELGIUM, FRANCE, FRG, ITALY, NETHERLANDS, NORWAY, UK) Current status of European studies is reported which aims near constant quality, shorter delays and more efficient use of network resources. Advantages and disadvantages of "one layer CBR, "one layer VBR", "two layer CBR/VBR" and "two layer VBR/VBR" are compared. Error concealment technique for protecting against bit errors and cell loss is also described. As a conclusion, unresolved issues consisting of ATM network issues and video coding issues are listed up. AVC-18 CONSIDERATIONS CONCERNING THE STANDARDISATION OF AAL(S) FOR VIDEO SERVICES (BELGIUM, FRANCE, FRG, ITALY, NETHERLANDS, NORWAY, UK) Problems to obtain AALs suitable for video services are listed up. It is proposed to distinguish between the following two approaches: - An AAL suitable for existing video services should be standardized in a relatively short term, taking into account compatibility issues. - An AAL matched with the video coding algorithm should be found. Requirements for the second category are also listed up. It is stressed that the second category AAL should be defined together with the new video coding algorithm. AVC-19 VIDEO CODEC DEVELOPED IN THE BELGIAN BROADBAND EXPERIMENT (RTT BELGIUM) Information on the sate of art video codec is provided. The hardware has two working modes; variable bit rate mode and adjustable fixed bit rate mode. Hardware configuration, VLSI implementation, and performance in terms of operating bit rates are also described. AVC-20 IMPACT OF THE ATM TECHNIQUE ON VIDEO CODING (BELL TELEPHONE) ATM characteristics which have impacts on video coding are overviewed; availability of high bandwidths, high bandwidth flexibility, variable bit rate capability, cell loss, cell jitter and packetization delay. Video coding techniques which adapt to the ATM network characteristics are also listed up; coding at high bit rates, multiplexing of service components, user selectable picture quality and bit rate, layered coding, cell loss correction and concealment, and service synchronization. AVC-21 TWELFTH MEETING REPORT OF ISO/IEC JTC1/SC2/WG11 (CONVENOR) This document reports MPEG meeting report held in Santa Clara in September 1990, covering WG11 plenary as well as subgroups consisting of MPEG/Video, MPEG/Audio, MPEG/Systems, MPEG/VLSI, MPEG/Tests and MPEG/DSM. Temporary Documents TD-1 Agenda for The Hague meeting (Chairman) TD-2 Available documents (Chairman) TD-3 List of tape demonstrations (Chairman) TD-4 Discussion items in the first meeting of the Experts Group (Chairman) TD-5 Work plan (Chairman) TD-6 Draft summary of Tuesday discussion on harmonization with other groups (Chairman) TD-7 Proposal for possible collaboration between SGXV/1 Experts Group on ATM video coding, ISO/MPEG and CMTT (Belgium) TD-8 Draft letter to Dr. L. Chiariglione, Convenor of ISO/IEC JTC1/SC2/WG11 (Small group on harmonization) TD-9 H.26x provisional requirements (Small group on harmonization) TD-10 Work plan - revised (Small group on harmonization) TD-11 First simplified network model (Small group on network model) TD-12 Draft liaison to SGXVIII - requirements for B-ISDN network model as it impacts on video coding (Small group on liaison to SGXVIII) TD-13 Draft report of the first meeting of the Experts Group for ATM Video Coding (Chairman) END Documents for the second meeting of the Experts Group Normal Documents AVC-22R REPORT OF THE FIRST MEETING OF THE EXPERTS GROUP FOR ATM VIDEO CODING IN THE HAGUE (CHAIRMAN) Achievements and action points obtained at the first meeting are recorded to facilitate our discussion at this meeting. AVC-23 REPORT OF MPEG BERLIN MEETING (CHAIRMAN) The following points of our concern are extracted from the MPEG meeting outcomes; - joint sessions with CCITT Experts Group are to be held, - MPEG Phase 2 work plan and milestones, - technical requirements from the CCITT point of view are to be further clarified, - test procedures for promising video coding algorithms. AVC-24 EXCERPT FROM WPXVIII/8 MEETING REPORT (CHAIRMAN) The following points of our concern are extracted from the WPXVIII/8 meeting report; - coordination of video coding aspects was initiated, - IVS baseline document (AVC-25) will be used as a vehicle to achieve this coordination, - some answers to our questions on the B-ISDN characteristics were provided with respect to network resource management and cell loss performance. AVC-25 INTEGRATED VIDEO SERVICES - IVS - BASELINE DOCUMENT (WORKING PARTY XVIII/8) This living document is intended to provide a framework for ongoing studies on the video service aspects of B-ISDN in order to ensure consistency with B-ISDN among the works of different standardization bodies. It is proposed that those groups have joint ownership of this document and that it be used as a vehicle to facilitate and promote discussion, liaison and agreements for IVS in B-ISDN. AVC-26 REPORT OF THE 13TH MEETING IN BERLIN (MPEG) This is reproduction of the complete report of the MPEG Berlin meeting held in December 1990. AVC-27 EXCERPT FROM THE REPORT OF THE GENEVA MEETING (WORKING PARTY XV/1) The following points of our concern are extracted from the WPXV/1 meeting report; - the first progress report of the Experts Group was approved, - "terms of reference" of the group was slightly extended to allow direct interaction with other CCITT Groups, - a comment was given on the balance between commonality and optimization of the video coding algorithm. AVC-28 LIAISON STATEMENT TO CCITT STUDY GROUP XV (TG CMTT/2) Common areas of interest between CCIR/CCITT TG CMTT/2 and Study Group XV are identified, leading to a practical collaboration method through the "Special Rapporteur for the second distribution of digital TV and HDTV." AVC-29 COMMON PROGRESSIVE PICTURE FORMAT FOR HIGH QUALITY APPLICATIONS (BELGIUM, FRANCE, FRG, ITALY, NORWAY, THE NETHERLANDS, UK) It is proposed that a common worldwide picture format be adopted also for high quality video applications, which has the following parameter values; - 60 frames/second - 576/288/288 lines for Y/U/V - 720/360/360 pels for Y/U/V - progressive. AVC-30 IMPROVEMENTS OF HYBRID DCT CODING (NORWAY) The following ideas have been tested for improving the coding performance of hybrid DCT coding schemes; - optimized quantizers for transform coefficients - less filtering for interpolating fractional pel positions - adaptive use of four different two-dimensional VLCs having 1-4 bits of EOB - prediction from two frames as alternative to interpolative coding - use of progressive images as input to the source coder Simulation results are presented in SNR vs bitrate as well as in processed pictures. AVC-31 ON BIT RATES IN A TWO-LAYER CODING SCHEME (RTT BELGIUM) Experimental data are given to the loss of coding efficiency for a 2-layer coding against a 1-layer coding in terms of bit rate overhead vs stepsize ratio between the two layers. VLC efficiency loss (in intra mode only) and impact of poor prediction due to low-accuracy loop (in inter/intra mode) are addressed. AVC-32 COMPATIBILITY METHODS FOR VIDEO CODING SYSTEMS (THE NETHERLANDS, FRG, NORWAY, ITALY, UK, SWEDEN, FRANCE, BELGIUM) Definitions are first given to "upward/downward compatibility" between different picture resolutions and "forward/backward compatibility" between different coding standards. Then the following methods of achieving these compatibilities are defined and discussed; simulcasting, embedded bit stream, syntactic extension, switchable encoder and standard families. It is proposed that the definitions form a basis for further discussions on the compatibility issue. AVC-33 SET UP OF CCIR 601 MULTI-PURPOSE CODING SCHEME (PTT RESEARCH, THE NETHERLANDS) The set up of a multi purpose coding scheme (MUPCOS) for CCIR 601 video signals is presented, where SIF signal for odd fields coded as MPEG-1 bit stream form a base layer. The second layer transmits information for even fields as well as information for additional quantization accuracy of the SIF signal. Simulation results are provided in the form of statistical data and processed pictures. This scheme features compatibility with H.261 on hardware level and compatibility with MPEG-1 on video-multiplex level. It is concluded that this compatibility has to be supported since the price for it is low. AVC-34 FRAMEWORK FOR STANDARDISATION OF VIDEO SERVICES ON THE B-ISDN (AUSTRALIA) This document identifies the long term objectives for video service provision on B-ISDN with its fundamental characteristics (cell based transport, very large capacity, great transport flexibility) considered and proposes a specific short term workplan to achieve these objectives, stressing the alignment with the B-ISDN developments. It is also stressed to have close collaboration with SGXVIII for ensuring that the network developments accommodate the features required to achieve desired functionality for the video services. AVC-35 ARCHITECTURE OF VIDEO SERVICE INTEGRATION ON THE B-ISDN (AUSTRALIA) After analyzing what integration means and comparing several methods (negotiation, simulcast, layered) to achieve it on B-ISDN, "flexible layering" method is proposed as a framework, where as many layers as necessary, practical or economical for a given service are used. It is also proposed to encourage other parties to adopt this framework. AVC-36 PICTURE FORMATS SUPPORTED BY VIDEO CODECS ON THE B-ISDN (AUSTRALIA) It is pointed out that an early decision of the picture formats which a coder will be capable of dealing with is essential for video services integration on B-ISDN. The following resolution capabilities are suggested as a basis of this decision; - videophone 192x144 luminance, 15Hz frame rate - videoconference 384x288 luminance, 30Hz frame rate - TV 768x576 luminance, 30Hz frame rate - HDTV 2048x1152 luminance, 60Hz frame rate AVC-37 MULTI-POINT VIDEO COMMUNICATION FOR B-ISDN (AUSTRALIA) Early consideration of multipoint systems is proposed to exploit B-ISDN characteristics such as bandwidth-on-demand, multi-casting, selective routing, dynamic adaptation of bandwidth and time-sliced decoding and multimedia multiplexing. It is proposed that these considerations should lead to development of appropriate signalling protocols by SGXI. AVC-38 A COMPARISON STUDY OF VBR vs CBR FOR CONVERSATIONAL SERVICES (AUSTRALIA) The advantages and new capabilities offered by VBR video transmission are first described. Then, experimental results are given on comparison of required network resources between VBR and CBR, reporting that VBR has an overall performance gain and a significant statistical multiplex gain on a subjective quality basis. It is also suggested that the VBR transmission should be supported by the new functionalities in signalling protocols. AVC-39 VIRTUAL CHANNELS FOR MULTIMEDIA SUPPORT IN THE B-ISDN (AUSTRALIA) It is proposed that early definition of arrangements for multimedia multiparty support should include the separation of multimedia connections into separate virtual channels. This method is characterized by the separation of call and connection control, individual usage monitoring for virtual channels, service specific processing of the network, and easy support for layered coding. A case study is given to the cross media delay for multiple virtual channels. AVC-40 RESPONSE TO INTEGRATED VIDEO SERVICES - IVS - BASELINE DOCUMENT (AUSTRALIA) It is recommended that the group formally endorse the IVS baseline document and establish a significant role in its evolution to coordinate between video service and network developments. Some texts are proposed for updating the baseline document with respect to the video service interworking methods and the network issues. AVC-41 STATISTICAL MULTIPLEX GAIN FOR VARIABLE BIT RATE VIDEO (RTT BELGIUM) It is argued that if both provides the same quality, VBR has always larger statistical multiplex gain than CBR since VBR is an "eroded" version of CBR. Several factors impacting the statistical multiplex gain are listed up; codec adaptability, noise in source, source bit rate, link bit rate, change in image contents, integration periods. It is concluded that there is no need to make a generic choice between CBR and VBR; CBR is a particular case of VBR. AVC-42 MULTIMEDIA MULTIPLEX IN ATM NETWORKS USED IN THE BELGIAN BROADBAND EXPERIMENT (BELGIUM) Multimedia multiplexing based on VCI multiplex is concluded as appropriate for B-ISDN because of the features; easy addition/deletion of service components during a call, service integration, information share among subscribers. Requirements on differential delay are analyzed with respect to delay due to transmission and routing through the ATM network and that due to packetization, coding and AAL. VP concept is concluded as not useful due to its quasi-static control. A solution in the Belgian Broadband Experiment is given which is based on the service component concept to meet the differential delay requirement. AVC-43 ATM NETWORK MODEL (SWEDEN, UK) The following three ATM network models are presented which provide the congestion probability; - Method of large deviation (as in the Annex 4 to AVC-22R) - Gaussian (Normal Distribution) model - Method of equivalent bursts AVC-44 CELL LEVEL STATISTICS FOR A TWO-LAYER CODING SCHEME (UK) Statistical data for information generation of a two-layer coding are presented, concluding that even for a videophone type sequence the source can be bursty, and that a relatively small buffer makes a significant difference to the shape of source. AVC-45 DESCRIPTION OF A COMPATIBLE CODING APPROACH FOR MPEG1 AND MPEG2 (UK) A compatible coding scheme are presented with coded results which codes CIF/SIF sized pictures and CCIR601 sized pictures. CCIR601 picture is first down converted to the SIF and then coded by MPEG1 coder as the base layer, then the difference between the original CCIR601 signal and the upconverted version of the local decoded base layer signal is coded by MPEG2 codes as the second layer. This scheme offers both forward and backward compatibilities between MPEG1 and MPEG2 (similarly H.261 and H.26X). AVC-46 CONSIDERATIONS ON PICTURE FORMAT IN ATM NETWORKS (JAPAN) It is proposed that the following items should be further investigated and confirmed toward defining an SCIF (Super CIF); - picture quality degradation due to format conversion - loss of coding efficiency by use of SCIF - delay due to format conversion. Some preliminary investigation results are presented for these items. Comments are also given on multiple format approaches which may eventually be used and on the areas where SCIF be adopted. AVC-47 CONSIDERATIONS ON STATISTICAL MULTIPLEX GAIN ACCORDING TO THE FIRST SIMPLIFIED NETWORK MODEL (JAPAN) Statistical multiplex gain (SMG) curves for VBR coding are provided based on the first CCITT network model. It is discussed that SMG becomes larger as network grows if we assume the link capacity increases accordingly, that the increase of SMG by allowing higher cell loss probability is rather limited and becomes even smaller as network grows, and that a service class which provides with reduced charge but with high cell loss may not be attractive. It is stressed that subjective evaluation of the VBR effectiveness against CBR is important, particularly under the restriction of Usage Parameter Control of the network. AVC-48 VBR CODING UNDER USAGE PARAMETER CONTROL (JAPAN) One of the possible methods for UPC is first described. Then, the following study items are suggested as essential for the study of VBR coding under the UPC imposed by the network; - averaging window size - coding parameter control under UPC - VBR framework which includes CBR as a particular case - end-to-end delay. AVC-49 SOME OBSERVATIONS ON VARIABLE BIT RATE CODED VIDEO SIGNALS (JAPAN) Observed average bit rates are provided for various sizes of sliding window; small (up to 0.1 frame period) and large (up to 300 frames period), concluding that instantaneous peak bit rate can be reduced significantly by a small buffer, and that some scenes show a large deviation of average rate but others not. Some considerations are also given on to what cases VBR becomes effective. AVC-50 CONSIDERATIONS ON CELL LOSS IN ATM NETWORKS (JAPAN) Requirements for cell loss ratio are first given. Then, several methods are described which cope with not ignorable cell losses; particularly, cell interleaving which is applicable only to higher bit rate coding, packetization which should be used in any case for quick recovery from the damage and layered coding which needs evaluation of coding efficiency. AVC-51 REQUIREMENTS OF THE HIGH QUALITY VIDEO CODING STANDARD H.26X - CONSIDERATION OF MULTIPOINT SYSTEMS, DISTRIBUTION SERVICES AND FUTURE ENHANCEMENT (JAPAN) The following items are provided to discuss the requirements for high quality video coding standard H.26X; - realization of multipoint systems, taking into account possibility that layered coding may be a solution, - inclusion of an intraframe only video codec in the scope of the new standard, - consideration of the future enhancement by means of the syntax structure. AVC-52 REVISION TO THE ANNEX 3 TO DOC. AVC-22R (JAPAN) Some enhancements to the questions for SGXVIII are proposed which further clarify the points of our concern by adding recent findings in required cell loss performance, statistical multiplex gain, VBR considerations with respect to UPC, multimedia multiplexing, etc. AVC-53 INVESTIGATION OF MULTIMEDIA MULTIPLEX ON ATM NETWORKS (JAPAN) In order to make discussion points clearer, it is suggested to first clarify the requirements on ATM networks from audiovisual terminal point of view. Required functions for an intermediate virtual "MUX" layer between "CS" layer and "User" layer are listed up for identifying those appropriate for networks. A preliminary delay analysis is also presented for multiplexing in CS, pointing out that the size of CS-PDU relative to the bit rate is essential. AVC-54 CLOCK RECOVERY FOR VARIABLE BIT RATE AUDIOVISUAL CODING (JAPAN) Several clock recovery methods are discussed attempting to clarify what is needed for variable bit rate audiovisual coding and what is to be reflected in the AAL Type 2. There are four cases; CS having no clock recovery function, clock recovery in one VC, clock recovery between multiple VCs from a terminal, clock recovery between multiple VCs from different terminals. AVC-55 H.261 COMPATIBLE 2-LAYER VIDEO CODEC WITH HIGH CELL LOSS RESILIENCE (DAIMLER-BENZ RESEARCH, FRG) Coding results are presented for a two-layer coding scheme where the first pass encodes the input original signal according to H.261 and the coded data packets are transmitted with high priority, while the second pass encodes the difference between the original signal and the locally decoded signal of the first pass with the identical H.261 coder and the resulting coded data packets are transmitted with low priority. This scheme is compatible with H.261 and very resilient to cell loss in the second layer, up to 10E-1. AVC-56 CONSTRAINTS ON VARIABLE BIT-RATE VIDEO FOR ATM NETWORKS (AT&T BELL LABS) Conditions are analyzed with inequality equations which ensure that the video encoder and decoder buffers do not overflow and underflow when the channel can transmit a variable bit rate. Based on this analysis, allowable variability in terms of number of bits per frame are given as a function of the network policing parameters. The existing constant bit rate channel case is treated as part of this generalized analysis. Finally there is described a means to select jointly the number of encoded bits for each video frame and the number of bits transmitted across the variable rate channel. AVC-57 PREPARATORY DRAFT PROPOSAL PACKAGE DESCRIPTION FOR MPEG PHASE 2 (MPEG) This is a collection of materials agreed or to be discussed for the MPEG Phase 2 work. Overall plan, requirements and picture quality testing method for video coding candidates are described. AVC-58 SIMULATION RESULTS FROM A SUBBAND SPLITTING CODING SCHEME COMPATIBLE WITH MPEG1/H261 (CNET) Coded results are presented for a coding scheme which encodes CCIR601 pictures maintaining compatibility with H.261 and MPEG1 standards. The input picture is first split into four subband sequences of SIF resolution by Hadamard transform matrixes. The base layer for the LL component conforms to H.261/MPEG1, the enhancement layers transmit coded data for the remaining three subbands as well as additional data to the base layer. In the current experiments, SM3 are used for all the four subbands. It is concluded that more investigations are needed in order to definitively know the interest of such a simple method, in particular in terms of tradeoff between loss of efficiency and simplicity. AVC-59 PICTURE FORMATS FOR HIGH QUALITY APPLICATIONS (CANADA) The following two picture formats are proposed for a single format for all high quality applications within a region; 525-line format 625-line format Frame rate 30/sec 25/sec Interlace progressive progressive No. of pels (Y/Cr/Cb) 720/360/360 720/360/360 No. of significant pels/line 704/352/352 704/352/352 No. of lines/frame (Y/Cr/Cb) 480/240/240 576/288/288 It is also proposed to reach agreement among CCITT, CMTT and ISO to support these formats for high quality applications. AVC-60 PICTURE FORMAT FOR HIGH QUALITY INTERACTIVE VIDEO SERVICES (BELLCORE) After having analyzed some fundamental requirements for selection of appropriate picture format(s), a common picture format with square pixel geometry is concluded as desirable to facilitate inter-region connections, to ease multipoint and bridging operations, and to realize integrated multimedia terminal. The parameter values are 528 lines/picture and 704 pels/line, 59.94 progressive pictures/sec for ATM teleconferencing. AVC-61 STATISTICAL ANALYSIS OF VIDEO TELECONFERENCE TRAFFIC IN ATM NETWORKS (BELLCORE) VBR coded data for a 30 minute sequence of video teleconferencing are analyzed to answer the questions of appropriate statistical model to represent coded data and appropriate video source model to be used for traffic studies. The major conclusions are as follows; - The number of cells per frame follows a gamma distribution, which is a stationary process in the absence of scene cuts and changes. - For traffic studies, neither an autoregressive model of order 2 nor a two-state Markov chain model is good, though the former fits the data well in a statistical sense. - A detailed Markov chain model with about 60 states is sufficiently accurate for use in traffic studies. AVC-62 A SIMULATION STUDY OF VIDEO TELECONFERENCE TRAFFIC IN ATM NETWORKS (BELLCORE) Using VBR coded data for a 30 minute sequence of video teleconferencing, cell loss and delay simulation results are provided for a case where 16 sources are transmitted through a single stage multiplexer with buffer of 4 ms and 5 ms delay. It is concluded that different sources with identical statistical characteristics can experience widely different cell loss rates, and that this difference is due to the inherent periodicity of video traffic which can be alleviated by a simple buffer scheduling mechanism. AVC-63 LIAISON STATEMENT TO CCITT WORKING PARTY XVIII/8 (TG CMTT/3) TG CMTT/3 gives an update for "Annex 4 - Video service interworking" of the "IVS Baseline Document", indicating several interworking techniques and advantages/disadvantages of the layered coding. Compatibility is also discussed in the light of "contribution" applications. AVC-64 ASPECTS ON PICTURE FORMAT FOR HIGH QUALITY APPLICATIONS (SWEDEN) Several aspects are listed up which impact the decision of a new picture format; application, compatibility, parameters, equipment. It is concluded that as much compatibility as possible shall exist among different applications, and that "distribution" and "future HDTV" aspects shall be given heavy weight in definition of a new picture format. A principle for compatibility between various applications, ranging from videophone to HDTV, is also presented. Temporary Documents TD-1 Agenda for the second meeting in Paris (Chairman) TD-2 Available documents (Chairman) TD-3 Draft status report on ATM video coding standardization (Experts Group) TD-4 List of tape demonstrations (Chairman) TD-5 Representatives to MPEG sub-groups (Chairman) TD-6 Editors for "Status Report" (Chairman) TD-7 Comparison of VBR/CBR coding - Framework for further study (Small group on VBR/CBR study) TD-8 Action plan for ATM picture format (Small group on picture format) TD-9 Draft liaison statement (Liaison Representative to CMTT/2) TD-10 Liaison to SGXVIII from SGXV Experts Group on Video Coding for ATM Networks (Small group on network issues) TD-11 Discussion results of the second meeting in Paris (Experts Group) TD-12 Draft report of the second meeting of the Experts Group for ATM Video Coding in Paris (Chairman) END Documents for the third meeting of the Experts Group 14-23 August 1991, Santa Clara Normal Documents AVC-65R REPORT OF THE SECOND MEETING OF THE EXPERTS GROUP FOR ATM VIDEO CODING IN PARIS (CHAIRMAN) Achievements and action points obtained at the second meeting are recorded to facilitate our discussion at this meeting. AVC-66 REPORT OF THE 14TH MPEG MEETING IN PARIS (MPEG) This document contains the recommendations of the Paris meeting and detailed meeting reports. AVC-67 LIAISON STATEMENTS AND MEETING NOTICE (SPECIAL RAPPORTEUR OF TG CMTT/2) Functional requirements for the secondary distribution of digital CTV, EDTV and HDTV signals to consumers are given on the following aspects; - real-time coding/decoding - minimum coding/decoding delay - automatic optimization to the picture content, network performance, etc. - picture formats covering CTV interlaced, EDTV/HDTV interlaced and progressive - quality objectives - no impairments in principle - graceful degradation for unusual significant level of errors - quality of normal real time delivery be not compromised for features - compatibilities among CTV, EDTV and HDTV - worthwhile commonality with other standards AVC-68 LIAISON STATEMENTS AND IVS BASELINE DOCUMENT (SGXVIII) Outcome of the June meeting which is relevant to our work is contained; status of discussion on CLP issues, status of agreements on UPC issues, and updated IVS Baseline Document. AVC-69 CLR AND BER PROTECTION FOR ENHANCED END-TO-END USERS QOS (RTT BELGIUM) An example of AAL Type 2 implementation is presented, which protects against bit errors and cell losses to obtain at least 2 hours errors free transmission for a bit rate range of 2 to 140 Mbit/s for BER=1E-6, CLR=1E-6. Bit error protection is with forward single error correction, while cell loss protection is with 4 bit Sequence Number and one parity cell added to the 31 service cells. Three critical cases are also analyzed which require slightly smaller CLR. AVC-70 UPDATED DRAFT PROPOSAL PACKAGE DESCRIPTION FOR MPEG PHASE 2 (CHAIR OF MPEG REQUIREMENTS SUB-GROUP) This is an update of the Paris meeting outcome based on the comments received from the collaborators. AVC-71 THE IMPACT OF THE NETWORK ON VIDEO CODING (AUSTRALIA) It is claimed that optimum performance of ATM video coding can not be obtained if source coding and channel coding are considered separately, and that the following ATM network characteristics should be taken into account for development of the ATM video coding; - cell loss resilience - effective use of cell loss priority - variable bit rate coding - flexible bandwidth allocation AVC-72 REQUIREMENTS FOR ATM VIDEO CODECS (AUSTRALIA) The following additions to the list of requirements on the ATM video codecs are proposed; 1) functional requirements - audio/video relative delay (portion assigned to codec) - support of continuous presence multipoint 2) compatibility / interworking requirements - capability of handling multiple coder input/output formats - backward/forward compatibilities with H.261 - interworking among systems with different spatial and temporal resolutions 3) network related requirements - rate control for VBR - control for two priority channels - error performance assessment under cell loss It is concluded that the full list of requirements be input to the IVS Baseline Document. AVC-73 ARCHITECTURE FOR VIDEO SERVICE PROVISION (AUSTRALIA) Flexible layering scheme is supported for the ATM video coding architecture, where signals are coded in multiple layers but lower layers may be switched off as necessary, thus providing the compatibility with existing coding schemes in the short term while allowing the coding scheme optimized for the B-ISDN. A three layer system with pyramidal decomposition of the input signals is given as example implementation. The importance of reaching a decision on the coder input formats defining layer boundaries is stressed by listing issues which impact on the decision; spatial resolution and frame rates, interlace or progressive scanning and pel aspect ratio. AVC-74 THE EFFICIENCY OF A LAYERED PYRAMID CODER (AUSTRALIA) Coding results are provided for a layered Laplacian Pyramid scheme, where the input CIF signal is decomposed into a QCIF base layer and an enhancement layer. Coding efficiency is compared between the single layer scheme and the Laplacian Pyramid scheme in terms of rate-distortion, where rate is counted as entropy of non-zero coefficients. It is concluded that the Laplacian Pyramid scheme is potentially as efficient as the single layer coder. AVC-75 SOURCE/NETWORK MODEL (AUSTRALIA) To improve accuracy of the network loading model, use of cell loss ratio CLR given in Eq.(2) instead of saturation probability Psat is proposed. Number of channels and statistical multiplex gain (SMG) are exemplified assuming a network model where all the cells exceeding network capacity are lost and a source model of Gaussian distribution, concluding that the Group's first network loading model provides conservative estimation of SMG. It is also stressed that understanding of the impact of the network characteristics on the coder will require a model of the cell loss burst behavior. AVC-76 VIRTUAL PATH SUPPORT OF MULTIMEDIA MULTIPLEXED (AUSTRALIA) The Virtual Path approach for ensuring cross media synchronization is concluded as not appropriate because of its semipermanent nature and mixed QOS requirements corresponding to respective media. It is proposed to make a request for the network to provide necessary signalling and control for bounded cross media delay by ensuring all media components follow a common physical path. This should be liaised to SGXVIII for action. AVC-77 THE SAR SUBLAYER OF AAL2 FOR VIDEO SERVICE SUPPORT (AUSTRALIA) Functionalities of SN, IT, LI and CRC in the current I.363 are reviewed from the VBR video service provision point of view, indicating that they may not be matched to the needs of video services, or even not required at all and suggesting that AAL Type 2 with minimum functionality may offer the flexibility to accommodate a wide and diverse range of video services. It is proposed that this matter be a priority issue of the Experts Group and that consideration should be given to a single SAR sublayer for both VBR and CBR with a liaison to SGXVIII advising our thought. AVC-78 REMOTE VIDEO SURVEILLANCE AS A B-ISDN SERVICE (AUSTRALIA) It is proposed that remote surveillance be added to the list of relevant applications being considered by the Experts Group (Table 1 of Status Report), as its characteristics are not entirely covered by other services. It is noted that the remote surveillance has such distinct characteristics as importance of ensuring a high coding quality for each frame for archiving and later retrieval, rapid removal of transmission error artifacts, wide variety of frame rates, frequent use of on-line panning, tilting, zooming, etc. AVC-79 LOSS OF CODING EFFICIENCY BY USING SCIF (JAPAN) Simulation results are reported for comparison of rate-distortion between coding the original 525/60 interlaced signals and coding the converted signals into progressive scan SCIF as in AVC-29. The loss of coding efficiency is found to be 25-30% for INTER and 35-30% for INTRA of "Flower GArden". It is concluded that further study is required, including the use of suitable VLC and/or better format conversion filters. AVC-80 CONVERSION SIMULATION BETWEEN 525 LINE INTERLACED FORMAT AND SCIF (JAPAN) Simulation results are reported on conversion from 525 line interlaced picture to 576 line progressive scan picture and back to the original interlaced picture. Used filters have 16 taps for interlace/progressive scan conversion and 31 taps for 480/576 line conversion. It is concluded that SNR and subjective investigation show satisfactory re-converted pictures but that further study is required on coding efficiency and additional hardware for adopting the SCIF approach. AVC-81 PROGRESSIVE SCANNING CAMERA (JAPAN) Present status for the development of progressive scan cameras in Japan is described as being still in an infant stage. AVC-82 MERITS AND DEMERITS OF THE PROGRESSIVE AND INTERLACED FORMATS (JAPAN) Two possible scanning systems for SCIF, interlace and progressive, are compared on the following items; - ease of layered coding - matching with current camera/display devices - coding efficiency - field parity identification AVC-83 COMPARISON OF PICTURE QUALITY AND ENCODING EFFICIENCY BETWEEN SCIF - SUPER CIF - AND INTERLACED FORMAT USING MPEG ENCODING (JAPAN) Simulation results are shown which compare the coding efficiency between the progressive (SCIF) and interlaced (ILF) formats by applying MPEG encoding separately to each original field. It is reported that though the SCF requires considerably more bits for a common step size (thus obtaining higher SNR) than ILF, both provide almost the same SNR for a common bit rate 4 mbit/s. A possible interpretation is also given. AVC-84 ADDITIONAL SUBMISSION MATERIALS FOR 'KURIHAMA TEST' (JAPAN) Considering that cell loss and its effect on video coding in the B-ISDN ATM environments, it is proposed that the following additional materials be submitted for the Kurihama test; - what will happen if cell loss occurs during transmission, description of cell loss protection, if any - additional delay due to the above cell loss protection - presentation of decoded pictures when cell loss occurred The first two should be mandatory, and the third be desirable. AVC-85 CONSIDERATION ON ACCEPTABLE PROCESSING DELAY IN THE VIDEO CODEC (JAPAN) Starting from the G.114 specifying that one way propagation time should be less than 400ms for "acceptable" audio quality, and considering that the acceptable delay for videophone is not different from telephone, acceptable codec delay is derived for three cases of transmission: optical, satellite and their combination with assumption of 50ms delay due to the ATM processing in the network portion. AVC-86 REQUIREMENTS FOR THE VIDEO CODING STANDARD H.26X (JAPAN) Expected terminals functions in the B-ISDN are first discussed from service integration, namely H.32X intercommunication with another H.32X, MCU, secondary distribution center and network database, as well as multipoint communications point of view. Then the following requirements are derived from them necessary functions to effectively utilize the B-ISDN; 1) H.26X video coding should incorporate H.261 for intercommunication. 2) It is sufficient in the terminal that only the decoder can cope with required service characteristics except for the case of conversational services. 3) Decoders may have full set of capabilities to fulfill the entire functionalities corresponding to respective services, but coders may implement limited set of functionalities specific to the application. 4) Embedded bit stream structure is a desirable coding architecture. 5) Realization of "Flexible Layering" can be a solution for these requirements. 6) Several received video streams may desirably be processed with simultaneous decoding (time-sliced decoding) at the decoder for continuous presence. AVC-87 CONSIDERATION ON MULTI-POINT COMMUNICATION IN B-ISDN (JAPAN) Three configurations for the continuous presence multipoint system are considered, out of which the following two cases need particular attention for the video coding; - A decoder receives multiple bit streams multiplexed from multiple sources and reconstruct respective pictures and provide them to separate displays (time sliced decoding). - A decoder receives a bit stream which contain a picture composed by an MCU from multiple sources. Coded bit streams should be edited without decoding and recoding at the MCU. AVC-88 THE EVALUATION OF SUBBAND CODING EFFICIENCY (JAPAN) Coding results are presented in rate-distortion curves and processed pictures which compare a two layered subband coding and a non-layered coding. The following observations are given; - The quantizer step size for N layered subband coding should be SQRT(N) times smaller than the step size of non-layered coding to provide the same SN. - Adjustment of MC size, MC precision and number of interpolation filter taps improves the subband coding efficiency. - The single layered coding performs better in rate-distortion characteristics, but the reconstructed pictures look almost the same. AVC-89 CONSIDERATIONS ON THE WINDOW SIZE OF TRAFFIC DESCRIPTOR (JAPAN) VBR coding simulation results are given when a particular long term average control scheme is applied to the coder. It is reported that several seconds are required in this coding control scheme for the window size of the traffic descriptor in the network to absorb the changes of of video sequences due to zooming of two seconds. AVC-90 CONSIDERATION ON DELAY WITH VBR CODING (JAPAN) Coding/decoding delay is analyzed for a VBR system with some assumptions of simplification. The size of the encoder output buffer is given as Sbuf(bits)=Ave(bit/T)*Swin(T) where Ave is average bit rate per frame period T and Swin is window size of the network UPC measured in frame time period T. Average bit rate is policed with moving window of size Swin here. Maximum delay is given as L=(Ave/Peak)*Swin where Peak is peak bit rate per frame period T. Some comparison with the discussion in AVC-56 is also given. AVC-91 MULTIMEDIA MULTIPLEX METHOD (JAPAN) Multimedia multiplex methods are discussed in the light of interworking between an H.32X terminal connected to B-ISDN and an H.320 terminal connected to N-ISDN. Some problems of using the VCI method for such interworking are first listed; low bit rate for each medium in H.320, speed of configuration change, provision of multimedia multiplex conversion in the gateway. Then user multiplex is suggested for such purpose, but pointing out the need of study on how to achieve VCI based multimedia multiplex with the interworking feature. Notion of "switchable" and "embedded" is illustrated for multimedia multiplex. AVC-92 VIRTUAL LAYER APPROACH FOR MULTIMEDIA MULTIPLEX FUNCTION (JAPAN) The virtual MUX layer approach is further discussed where the MUX layer is placed between codecs and the network (AAL) for logical multimedia multiplexing functions as presented in AVC-53. Necessary functions of this MUX layer are listed; such as packetization in variable length of each media information, recovery of end-to-end synchronization of each media information, handling of AAL-SDU for lost and errored cell, etc. Mapping of these MUX layer functions to AAL functions are also given. AVC-93 REQUIREMENTS TO THE FUNCTION OF AAL TYPE 1 (JAPAN) Requirements to the CS layer functions of AAL Type 1 are proposed for liaison to SGXVIII in the light of video transmission and its impact to AAL Type 2. - error correction: interleaving should be optional, cell loss notification is indispensable for the video decoder. - 8 kHz timing is necessary for interworking with existing terminals - clock: inquiry should be made whether submultiples of 155.52 MHz are available, recovery of video signal clock may be required. AVC-94 COMPATIBLE CODING OF CCIR 601 IMAGES: PREDICT THE PREDICTION ERROR (PTT RESEARCH - THE NETHERLANDS) Modifications to the multi purpose coding scheme, which has upward and downward compatibility with H.261 or MPEG1 and was presented in AVC-33, are provided with D1 tape demonstrations for both of full CCIR 601 resolutions and SIF resolution results. A second DPCM loop operating on CCIR 601 resolution is added so that two prediction errors are computed: one based on a SIF prediction and one based on the full resolution, the SIF quantized prediction error signal being used for prediction for the full resolution prediction error signal. By switching off the first loop, this system can operate in a non-compatible mode as well. AVC-95 ESTABLISHMENT OF NEW SC29 (CONVENOR OF ISO/IEC JTC1/SC2/WG8) It is announced that SC29 has been established which covers audio, visual and multimedia coding fields. AVC-96 STATUS REPORT ON ATM VIDEO CODING STANDARDIZATION (EXPERTS GROUP) Study results as well as further study items are summarized for common understanding among members of the the group and publicity of the group's activities. This is a version updated according to the Paris meeting outcome. AVC-97 COMPARISON OF NETWORK LOADING MODELS FOR TWO LAYER VARIABLE BIT RATE CODING (UK) It is concluded that the Large Deviation model adopted in the Group's first network loading model is more appropriate than other ones in that it is a safe conservative model independent of the source modeling and that the practical network resource management is more correctly reflected, by giving an equation for the cell loss ratio CLR instead of the probability of saturation Psat. A comparison of number of accommodated channels is given between estimates based on CLR and Psat, indicating that the use of Psat is practically sufficient when about 1000 channels are multiplexed. AVC-98 REQUIREMENTS ANALYSIS FOR VIDEO SERVICES (RTT BELGIUM) Impacts of video service requirements on ATM network parameters and required error handling are discussed for possible upgrading of the IVS Baseline Document. Based on the necessary error free time for each service, bit error handling is first investigated with the ATM payload scrambling taken into account. It is concluded that some bit error protection is mandatory for video services even in case of BER=1E-8, and that the payload scrambling weaken the error correction capability of existing codes such as BCH(511,493) of H.261. Then cell loss handling is investigated, concluding that at least its detection is essential, and that a single cell loss correction is required for the most demanding TV distribution services even for CLR=1E-8. Comments are also given to possible interaction between bit error correction and cell loss correction, bursty cell loss correction and cell loss concealment. AVC-99 VBR VIDEO STATISTICS (RTT BELGIUM) The number of 112 bit subpackets per frame are recorded for the four different type of video services; video telephony, videoconferencing, normal quality broadcast video, high quality broadcast video. An adaptive DPCM codec is used for this measurement which adaptively selects intrafield prediction, interframe prediction and conditional replenishment. This paper is accompanied by a floppy disk containing the recorded data. AVC-100 LAYERED CODING FOR COMPATIBILITY (UK) Coded results are presented for a "pel split" layered coding scheme which uses the MPEG-1 coded pictures as a prediction for the MPEG-2 pictures and has three possible prediction modes for each field; MPEG-1, previous field and previous frame. MPEG-1 bit stream is embedded in the composite bit stream. By switching off the MPEG-1 prediction mode, this scheme becomes a MPEG-2 single layered scheme. AVC-101 COMMENTS ON THE IVS BASELINE DOCUMENT AVC-25 (BELGIUM, FRANCE, FRG, NORWAY, THE NETHERLANDS, SWEDEN, UK) Comments on the following items are proposed for upgrading the IVS Baseline Document; - work plan: consideration of video service requirements such as in AVC- 98 when defining service dependent CS - service bit rates: concern with CLP bit change by the network - QOS provided by the ATM layer: clarification needed - general: stress on multimedia system aspects required AVC-102 COMMENTS ON PICTURE FORMAT - ANNEX 3 TO DOC. AVC-65R (BELGIUM, FRANCE, FRG, NORWAY, THE NETHERLANDS, SWEDEN, UK) It is proposed that one additional format is required beside QCIF and CIF for communication services, whose parameter values are as in AVC-29, awaiting firm supporting evidence concerning quality degradation loss of coding efficiency due to scan conversion by the beginning of 1992. It is also proposed that a future standard should leave the door open for use of other formats. AVC-103 SIMULATION RESULTS ON A PEL SPLIT COMPATIBLE ALGORITHM (CNET - FRANCE TELECOM) Coded results are presented for a "pel split" scheme as summarized above (AVC-100). Numerical data and processed pictures are given for MPEG-1 coding, MPEG-2 compatible coding and MPEG-2 non compatible coding. AVC-104 SUMMARY DESCRIPTION OF VADIS/COST ALGORITHM GROUP 2 FORWARD PREDICTION METHOD (NORWAY) Two factors contributing to the good subjective quality demonstrated at the Paris meeting (AVC-30) are described are described: - multiple two-dimensional VLC's for DCT coefficient coding which have EOB of 1-3 bits and are switched adaptively for each coefficient without side information - dual frame prediction which uses only forward prediction with two preceding frames This scheme is characterized by low delay and simple architecture. AVC-105 TERMINOLOGY CHAPTER FOR THE STATUS REPORT (DIS, NCS) Definitions of relevant terms are provided for inclusion in 2 of the status report. Temporary Documents TD-1 Agenda for the third meeting in Santa Clara (Chairman) TD-2 Available documents (Chairman) TD-3 List of tape demonstrations (Chairman) TD-4 List of picture formats (Chairman) TD-5 Agreements and action points for the picture format issue (Small group on picture format) TD-6 Framework for discussion of H.26X format(Small group on picture format) TD-7 Additional submission materials for the "Kurihama Tests" (Experts Group) and a diagram illustrating N-ISDN and B-ISDN interworking (Chairman) TD-8 H.26X requirements (Small group on requirements) TD-9 Liaison statement to SGXVIII (Small group on SGXVIII liaison) TD-10 Liaison to TG CMTT/2 SRG (Liaison representative) TD-11 Draft report of the third meeting of the Experts Group for ATM Video Coding in Santa Clara (Chairman) END Documents for the fourth meeting of the Experts Group 18-29 December 1991, Yokosuka Normal Documents Note: Contributions with "*" have also been submitted to MPEG. AVC-106R REPORT OF THE THIRD MEETING OF THE EXPERTS GROUP FOR ATM VIDEO CODING IN SANTA CLARA - PART I (CHAIRMAN) Achievements and action points obtained at the third meeting (CCITT sole sessions) are recorded to facilitate our discussion at this meeting. AVC-107R REPORT OF THE THIRD MEETING OF THE EXPERTS GROUP FOR ATM VIDEO CODING IN SANTA CLARA - PART II (CHAIRMAN) Achievements and action points obtained at the third meeting (MPEG/CCITT EG joint sessions) are recorded to facilitate our discussion at this meeting. AVC-108 PROPOSAL PACKAGE DESCRIPTION FOR MPEG PHASE 2 (CHAIR OF MPEG/REQUIREMENTS SUB-GROUP) This is the version updated according to the outcome of the Santa Clara meeting in August 1991. AVC-109 STATUS REPORT ON ATM VIDEO CODING STANDARDIZATION, ISSUE 2 (EXPERTS GROUP) Study results as well as further study items are summarized for common understanding among members of the the group and publicity of the group's activities. This is a version updated according to the Santa Clara meeting outcome. AVC-110 MEETING REPORT (ITU IVS CO-ORDINATION MEETING) IVS co-ordination meeting was held to align the development of network standards and that of video coding standards. Harmonization among video coding related standardization was also intended. As outcome of the meeting, standardization timetables were produced, and a number of action points together with responsible persons for each point were identified. AVC-111 ACTIVITIES OF CCIR SG11 FOR DIGITAL TELEVISION (CHAIRMAN OF WP-11B) This document presents CCIR SG11 activities that have been found closely related to ours in the IVS coordination meeting. They are going to work on digital emission of HDTV (and other television?) signals, and to study generic video coding covering terrestrial and satellite emission as well as secondary distribution through cables. We should be conscious of CCIR SG11 in addition to MPEG and CMTT/2 for our successful work. AVC-112 REPORT OF MEETING (WPXVIII/8-5, 8-3) Outcome of the Rapporteur's meeting on AAL Type 1 and Type 3,4 is reported, listing some open items as well. AVC-113 PICTURE FORMAT FOR CONVERSATIONAL VIDEO APPLICATIONS (CANADA) Experimental results are provided on the impact of 480 to 576 to 480 lines conversion (with 30 Hz frame rate) for 525-line TV systems, concluding that using a high-order vertical filtering results in no visible quality degradation and that coding efficiency loss due to the use of 576-line format is less than 3%. AVC-114* ATM COMPENDIUM (THE NETHERLANDS, BELGIUM, FRG, FRANCE, SWEDEN, ITALY, GREEK, UK) Information is provided on a European living document for the area of ATM video coding, which is a collection of work carried out in ETSI NA5 VCM and Cost 211ter. AVC-115* FEATURES OF MUPCOS (PTT RESEARCH, THE NETHERLANDS) Implementation methods and obtained performance are provided for features such as MPEG1/H.261 forward/backward compatibility, upward/downward compatibility, low end-to-end delay, cell loss resilience, scalability. AVC-116 BUFFERING AND DELAYS FOR A SLIDING WINDOW CONSTRAINT (AT&T) This document gives the delay and the encoder and decoder buffer sizes that allow any encoded bit-stream conforming to a peak-plus-sliding window channel rate constraint to be transmitted and decoded. The post-coding buffer solution is shown as much cheaper in implementation compared to the display buffer solution described in AVC-90. AVC-117* CELL LOSS RESILIENCE IN A TWO-LAYER CODING SCHEME (UK) Experimental results are reported on the effect of cell loss in a two- layered scheme that has a guaranteed CBR path for base layer and a cell loss susceptible VBR enhancement layer carrying difference between the DCT coefficients of the base layer and their quantized values. It is concluded that for cell loss ratios of 1 in 10 the picture quality degradation is negligible when 50% of the bits are spent in coding the base layer information. AVC-118* Algorithm proposal (BT) AVC-119 LAYERED INTERFRAME CODING SYSTEM BASED ON MOTION QUANTITY (JAPAN) Information is provided on a H.261 based layered coding scheme where large movement blocks are assigned to the high priority cells and the small movement blocks to the low priority cells. Two frame memories are used in the prediction loop, one of which stores full video signals including low priority blocks while the other stores only the high priority block signals. This scheme is characterized by the fact that full-band prediction is used at normal state, and that interframe prediction is applied even after cell loss happens in the low priority blocks. Some experimental results are presented. AVC-120* CELL LOSS RECOVERY BY CODING ALGORITHM (JAPAN) Various cell loss recovery methods are listed with focus on the necessary elements in the standard; leaky prediction, layered coding, cyclic refresh, demand refresh, error concealment and packetization. AVC-121 VIDEO CLOCK JUSTIFICATION (JAPAN) Necessity of video clock transmission for H.26X codecs is pointed out. Three possible methods for this purpose are outlined; use of the network clock as a reference, use of temporal reference in the coded video signal and use of the AAL function. It is concluded that this matter should be discussed and decided at an early stage. AVC-122 COMPARISON BETWEEN COMPATIBLE AND NON-COMPATIBLE CODING (JAPAN) Simulation results are reported on a hierarchical coding scheme proposed for the Kurihama tests (see AVC-150). This scheme can operate in downward compatible mode, upward compatible mode and non-compatible mode. Coding efficiency loss due to compatible coding has been found as 1.6 dB at both 4 and 9 Mbit/s for Flower Garden. AVC-123* INTERWORKING OF H.32X TERMINALS (JAPAN) Interworking methods of H.32X terminals with various terminals are discussed from the bit stream level compatibility and algorithm level compatibility. The followings are pointed out; - H.32X terminal must have bit stream level compatibility with H.261. - Conversion between different service classes becomes easier by a unified source coding algorithm. - This conversion in video multiplex and/or transmission coding should be kept as necessary minimum by proper design. AVC-124* CONSIDERATIONS ON PROCESSING DELAY WITH HYBRID CODING (JAPAN) Analysis of processing delay for hybrid codecs is presented to identify the most demanding elements that require more than one frame time. Format conversion, frame reordering for bidirectional prediction are those factors. Transmission buffer causes another significant delay in CBR, but it can be eliminated in VBR. AVC-125 SCIF ON A SQUARE PIXEL DISPLAY (JAPAN) Experimental results are given for displaying a 16:15 pel aspect ratio signal (720 pels/line x 576 lines) on a square pixel display, concluding that this 6% error causes distinguishable geometric distortion unless proper compensation is carried out. AVC-126 OPTIMIZATION OF 2-D VLC FOR SCIF CODING (JAPAN) Some experimental results are provided to clarify possibilities of coding efficiency improvements through optimizing 2-d VLCs for coding through a progressive SCIF (720 pels/line, 576 lines per picture, 59.94 pictures per sec). It is concluded that we can not expect to save coding efficiency loss due to the use of progressive SCIF by optimizing the 2-d VLC for INTER pictures, but that use of an optimized 2-d VLC for INTRA improves coding efficiency by up to 10%. AVC-127 TRANSITION OF THE BUFFER OCCUPANCY UNDER VBR ENVIRONMENTS (JAPAN) Experimental results are reported on the leaky bucket occupancy when 89 frames of "Edited Sequence" are coded with H.261 and rate controlled by a certain method (see AVC-89). Findings are that coding rate control with short response time and a low coding rate provide small value of BOCmax and that a transmission rate slightly higher than the coding rate makes BOCmax quite small. AVC-128 COMPARISON BETWEEN SLIDING WINDOW AND LEAKY BUCKET AS A UPC MECHANISM (JAPAN) This document compares two average rate monitoring methods, "sliding window" and "leaky bucket," assuming a simple square wave source model for information generation. It is concluded that "leaky bucket" is a more suitable UPC mechanism for video coding at least from transmission efficiency. AVC-129 COMPARISON OF MULTIMEDIA MULTIPLEX (JAPAN) Three multimedia multiplex methods, cell multiplex (VCI approach), SAR multiplex (packet approach) and user multiplex approach (H.221 approach) are compared in terms of channel utilization, compatibility with H.320 and MPEG, multimedia aspect, cell loss influence, etc. The logical interface between virtual media control layer and upper layer (e.g. video codec) is illustrated and necessary functions of the media control layer are listed for each of the three approaches. It is concluded that we need further study to definitely adopt the VCI approach. AVC-130 REQUIREMENTS FOR SGXVIII (JAPAN) The following items are listed for request (a,b) and question (c,d); a. video clock transmission, network clock to be provided for the terminal, timing information in AAL b. definition of standard DOS for international connections c. UPC mechanism and its standardization d. Negotiation for use of VCI's in multimedia communication AVC-131 NETWORK MODELS (SWEDEN, BELGIUM, FRANCE, FRG, GREEK, ITALY, THE NETHERLANDS, UK) The following three ATM network models are presented which provide the congestion probability Psat and cell loss ratio CLR; - Method of large deviation (as in the reference model) - Gaussian (Normal Distribution) model - Method of equivalent bursts The first model gives more pessimistic statistical multiplex gain than the other two models that are both based on mean and variance. It is stated that though Psat and CLR are different in 2 orders of magnitude, the number of allowable calls is only 5% different. Some calculation examples for the number of allowable calls are also provided. AVC-132 POLICING FUNCTION FOR VBR CODING (SWEDEN, BELGIUM, FRANCE, FRG, GREEK, ITALY, THE NETHERLANDS, UK) It is proposed that the SGXV undertakes some action to actively try to specify some policing functions for VBR video coding. AVC-133 Algorithm proposal (PTT Research) AVC-134 PICTURE FORMAT CONSIDERATIONS (AUSTRALIA) The concept of flexible spatial resolutions and frame rates as proposed in AVC-36 is supported. A number of questions raised at the previous meeting are discussed in detail, leading to the above conclusion. It is stressed that the ability to code sources which have frame rates not related to 59.94 Hz coder rate, proposed for SCIF, by integer factors, is essential. AVC-135 FLEXIBLE LAYERED CODING EFFICIENCY (AUSTRALIA) A layered coding structure for interworking between different service classes, which implements the flexible layering concept, is outlined. Several potential sources of inefficiency in layered coders have been identified; appropriate motion compensation in different layers, critical sampling, incremental signal coding in the higher layer. Work is currently being carried out to remove these sources of inefficiency. AVC-136 B-ISDN MULTIMEDIA SERVICE INTERWORKING (AUSTRALIA) The following three multimedia multiplex methods are compared in terms of interworking between H.32X and H.320 terminals for different communication scenarios; - User multiplex that multiplexes the multimedia into H.221 frame structure - Cell-base multiplex that supports the multimedia with different VCs - Hybrid multiplex that combine features of the user multiplex and the cell-base multiplex It is concluded that the importance of cell-base multiplexing for longer term terminal interworking scenarios is strongly identified, together with the possible interim, short term role of user and hybrid multiplexing. AVC-137 B-ISDN NETWORK STANDARDIZATION - ITS IMPACT ON THE DEVELOPMENT OF ATM VIDEO CODING (AUSTRALIA) After a review on recent activity in defining the scope and intent of B-ISDN network standards, particularly staged service support capabilities, resource allocation strategies, charging principles and B-ISDN performance, it is proposed for the Experts Group to take a similarly staged approach to develop appropriate video coding standards. It is also proposed that SGXV should provide an indication of the likely range of required cell loss performance values to ensure flexible and efficient coding. AVC-138 SECOND PROGRESS REPORT TO WPXV/1 (CHAIRMAN) There are reported major achievements since February, toward defining Recommendation H.26X for high quality video coding in the ATM environments. Particular items needing consideration of WPXV/1 are also raised; formal aspects of collaboration with other standardization bodies and study on system aspects such as multimedia multiplexing. AVC-139 TRANSPORT AND ERROR CONCEALMENT FOR MPEG-2 (DAVID SARNOFF RESEARCH, THOMSON CONSUMER ELECTRONICS) A packet-oriented transport format for a specific MPEG-2 algorithm proposal (see AVC-159) is described. The transport format contains "data link level" containing generic transport information (such as priority indicator, service ID) and "adaptation level" containing video related information fields (such as slice/MB pointer, slice/MB number, picture #, picture type) that aids error recovery at the video decoder. The use of HP/LP data types allow partitioning subjectively important and less important bit-streams when appropriate transmission facilities are available. Possible error concealment methods as well as cell loss simulation results are described. AVC-140 STATISTICAL MULTIPLEX GAINS FOR VARIABLE BIT RATE (BELGIUM, FRANCE, FRG, GREEK, ITALY, THE NETHERLANDS, SWEDEN, UK) It is argued that if both provides the same quality, VBR has always larger statistical multiplex gain than CBR since VBR is an "eroded" version of CBR. Several factors impacting the statistical multiplex gain are listed up; codec adaptability, noise in source, source bit rate, link bit rate, change in image contents, integration periods. It is concluded that there is no need to make a generic choice between CBR and VBR; CBR is a particular case of VBR. AVC-141 to 168 Algorithm proposals AVC-169 PICTURE FORMAT FOR HIGH QUALITY INTERACTIVE VIDEO SERVICES (BELLCORE) Simulation results are presented on a coding efficiency comparison between a SCIF with 576x720 spatial resolution and a SCIF with 528x720 spatial resolution (square pixel), concluding that the latter format is on average 5.5% more efficient than the former. AVC-170 ATM CELL HEADER FIELD (BELLCORE) Several questions on the ATM cell header field are brought to the Experts Group's attention; availability of CLP field to the receiver end user, tagging compliant cells at the edge of network, support of user information by the existing ATM cell header field, and number of cell loss performance objectives. AVC-171 STATISTICAL ANALYSIS OF VIDEO TELECONFERENCE TRAFFIC (BELLCORE) Histograms and Q-Q plots are provided for the number of cells per frame in "viconf" and "viphone" sequences which were provided by Alcatel Bell (see AVC-99), concluding that it follows a gamma distribution. AVC-172 DSM/ATM WORKSHOP (EXPERTS GROUP) Collection of the following four talks given during the MPEG/CCITT EG joint sessions at JVC-Kurihama on 20 November 1991; M. Biggar Broadband ISDN evolution O. Poncin ATM network characteristics T. Tanaka VBR aspects G. Morrison Video coding techniques suitable for utilizing ATM network characteristics AVC-173 PRELIMINARY FUNCTIONAL REQUIREMENTS FOR SECONDARY DISTRIBUTION OF TV AND HDTV SIGNALS (TG CMTT/2 SRG) This is an update of the previous document AVC-67. AVC-174 REPORT OF THE ACTIVITIES OF THE GROUPS OF EXPERTS ASSISTING THE SPECIAL RAPPORTEUR (TG CMTT/2 SRG) Work progress is reported covering 4 meetings since May 1991. It is noted that CMTT/2 SRG are confident; - that a family of formats can be defined for 50 or 59.94/60 Hz systems, - that the same algorithm scheme can be adopted for both the families, - that compatibility between 50 Hz and 59.94 Hz is not a requirement at the decoder. Two examples of compatible coding structures are given; both of which use a progressive or interlaced format for CTV and EDTV, while compatibility between this format and HDTV format is achieved by pyramidal coding. AVC-175 RESOLUTIONS ADOPTED DURING THE FIRST PLENARY MEETING OF ISO/IEC JTC1/SC29, 21-23 NOVEMBER 1991, IN TOKYO, JAPAN (SECDREATRIAT ISO/IEC JTC1/SC29) Decisions made at the first meeting of ISO/IEC JTC1/SC29 are brought to the Experts Group's attention; acivities of the groups under its umbrella and the relation to other groups. AVC-176 PICTURE PERFORMANCE OF 1.3, 4 AND 9 MBIT/S BELLCORE ALGORITHMS AND OTHER TEST PROCESSES (BELLCORE, NTT) Subjective study results are reported on the picture quality evaluation of compressed bit rate algorithms operating at 1.3, 4 and 9 Mbit/s, and the picture quality of other benchmark test processes (NTSC, VHS VCR). The subjective test plan is also detailed. ALGORITHM PROPOSAL DOCUMENTS SUBMITTED FOR THE KURIHAMA TESTS Note: "#nn" indicates the MPEG pre-registration number. AVC-118 MPEG91/207 #08 BT Labs AVC-133 MPEG91/215,216 #18,19 PTT Research, LEP-Philips, PRL-Philips AVC-141 MPEG91/201 #02 AT&T AVC-142 MPEG91/202 #03 Aware (I) AVC-143 MPEG91/203 #04 Aware (II) AVC-144 MPEG91/204 #05 Bellcore, NTT AVC-145 MPEG91/206 #06 BBC et al. AVC-146 MPEG91/206 #07 NTA AVC-147 MPEG91/208 #09 CCETT et al. AVC-148 MPEG91/209 #11 GCT et al. AVC-149 MPEG91/210 #12 HHI AVC-150 MPEG91/211 #13 Hitachi, Fujitsu AVC-151 MPEG91/212 #14 IBM AVC-152 MPEG91/213 #16 JVC AVC-153 MPEG91/214 #17 KDD AVC-154 MPEG91/217 #22 Matsushita AVC-155 MPEG91/218 #23 MIT AVC-156 MPEG91/219 #24 Mitsubishi AVC-157 MPEG91/220 #25 NEC et al. AVC-158 MPEG91/221 #26 NHK AVC-159 MPEG91/223,255 #27,28,35 TCE, PCE, David Sarnoff, PTT Research AVC-160 MPEG91/224 #30 RTT, UCL AVC-161 MPEG91/225 #31 Sharp AVC-162 MPEG91/226 #33 SONY AVC-163 MPEG91/227 #34 Thomson-CSF/LER AVC-164 MPEG91/228 #36 Toshiba AVC-165 MPEG91/229 #37 UCL AVC-166 MPEG91/230 #38 Waseda University AVC-168 MPEG91/231 #39 Columbia University AVC-151 MPEG91/232 #40 EPFL Temporary Documents TD-1 Agenda for the fourth meeting in Yokosuka (Chairman) TD-2 Available documents (Chairman) TD-3 List of tape demonstrations (Chairman) tD-4 Summary of proposals (MPEG/VIDEO and REQUIREMENTS) TD-5 Subjective test results of MPEG-2 (MPEG/TEST) TD-6 Summary of discussion (MPEG/VIDEO and REQUIREMENTS) TD-7 Meeting report (Chairman, WPXV/1) TD-8 Guiding principles for the Singapore meeting (Small group) TD-9 Definition of end to end delay (Small group) TD-10 Addendum to liaison statement from CCITT SGXV Experts Group on Video Coding for ATM Networks (Small group) TD-11 Draft report of the fourth meeting in Yokosuka (Chairman) END Documents for the fifth meeting of the Experts Group 6-9 January 1992, Singapore Normal Documents Note: Contributions with "*" have also been submitted to MPEG. AVC-177R REPORT OF THE FOURTH MEETING OF THE EXPERTS GROUP FOR ATM VIDEO CODING IN YOKOSUKA (CHAIRMAN) Achievements and action points obtained at the fourth meeting are recorded to facilitate our discussion at this meeting. AVC-178 (reserved for the report of SGXVIII meeting in Melbourne) AVC-179* DEFINITION OF END TO END DELAY (CCITT EXPERTS GROUP) All possible delays are described in a general way so that they can be applied to various coding schemes. The aim is to allow a proper comparison between coding schemes and to give reasonable grounds for determining the delay budget among the elements constituting end to end delay. AVC-180 SUBJECTIVE TEST RESULTS OF MPEG-2, KURIHAMA MEETING (CHAIRMAN OF MPEG/TEST) This is the official report of the Kurihama subjective test for proposed video coding algorithms. List of proposals, list of assessors, testing and data processing methods and test results are given. AVC-181* EFFICIENT FLEXIBLE LAYERED CODING (AUSTRALIAN "UNIVERSAL VIDEO CODEC" PROJECT) The source of inefficiency which arise in layered coders, and methods which can be used to reduce inefficiency, are described. Experimental results for a combined subband/pyramid scheme are presented to show that layered coders can be quite efficient in comparison with non-layered coders. It is suggested that the general principles should be useful in the design of efficient layered coders. AVC-182 PATENT INFORMATION (DAIMLER-BENZ) Information is given on a filed patent regarding cell loss concealment method. AVC-183* CORE EXPERIMENT ON COMPATIBILITY (BT) This document proposes a method of modifying SM3 to produce a first Test Model for MPEG-2 which maintains compatibility with MPEG-1 by incorporating a compatible prediction mode. Items of the core experiment are also proposed; simulcast vs compatibility, performance of various up-conversion schemes, down-sampling methods to generate the SIF, improvements by use of motion compensation to the MPEG-1 prediction etc. AVC-184* SIMULATION RESULTS OF PROPOSAL 30 (RTT BELGIUM) It is informed that the submitted D1 tape suffered from field inversion except Mobile & Calendar at 9 Mbit/s. AVC-185* EXPERIMENT OF LOW DELAY MODE (GCT) Four prediction modes (IP, IP'P, IBP and IBBP) are compared on a frame-based SM3 algorithm at 4 Mbit/s, concluding that the IBBP mode performs the best in terms of average SNR. AVC-186 LOW DELAY CODING MODE (FUJITSU) Three prediction modes (IPB, IPP' and IP) are compared on a field-based MPEG- 1 algorithm at 4 and 9 Mbit/s, concluding that backward prediction contributes to improving average luminance SNR by 1.8 dB and 1.4 dB in sacrifice of coding/decoding delay. AVC-187* CODING EFFICIENCY IN LOW DELAY MODE (KDD) Two prediction modes are compared on a field-base SM3; IBBP with N=30, M=3 and IP with N=15 and M=1. It is found that IBBP performs better in luminance SNR by 5 dB. AVC-188* COMPARISON AMONG COMPATIBLE CODING, NON-COMPATIBLE CODING, AND SIMULCAST (FUJITSU) The three coding modes are compared in a Hierarchical Laplacian Pyramid Coding scheme, providing SNR data at 4 Mbit/s and 9 Mbit/s. The layered coding looks effective at 4 Mbit/s, but it performs similarly to the simulcast coding at 9 Mbit/s. AVC-189* COMPARISON BETWEEN PYRAMID (EMBEDDED) AND SIMULCAST (TOSHIBA) The two coding modes are compared in an RM8-based coding scheme where the base layer has either of CIF or QCIF resolution. It is found that the simulcast mode performs better than the pyramidal mode supposedly due to the fact that motion compensation becomes less effective for the differential signal in the pyramidal scheme. AVC-190* CONSIDERATIONS ON CELL LOSS RECOVERY TECHNIQUES (JAPAN) The following five techniques for the cell loss recovery are detailed; leaky prediction, demand refresh, error concealment, video multiplex structure, and packetization. Items of standardization are pointed out. AVC-191* RATE CONTROL METHOD BASED ON SUB-BAND CODING FOR VBR TRANSMISSION (OKI ELECTRIC) Experimental results are reported on a control method for maximum coding rate, measured with 1 frame time jumping window, in a 7 sub-band coding scheme. The control method is to start with the previous frame quantizer step sizes and adjust them in the order of UU, UL, LU, LLUU, LLUL and LLLU band. AVC-192* COMPARISON OF PREDICTION/CODING METHODS IN AN RM8-BASED SCHEME (NTT) Three prediction/coding methods (frame, field and adaptive) are compared in an RM8-based coding scheme in terms of rate vs distortion characteristics. It is concluded that frame coding with simple field merging is a reasonable starting point and that if field mode is the choice two preceding fields should be used for motion compensated prediction. AVC-193* OBSERVATION OF SEQUENCES WITH CYCLICALLY DISTORTED PICTURES (NTT) Flower Garden sequence is processed by inserting intra coded pictures with constant step size in every other frame. Just noticeable degradation is given for the three parts; flowers, roof tile, and twigs. A possibility of exploiting cyclic coarse quantization is suggested but not firmly concluded. AVC-194* FIELD ADJUSTED MC FOR FRAME-BASE CODING (MATSUSHITA) A new motion compensation method is proposed for the frame-based coding of interlaced pictures, hence for TM0. A motion vector is sent per MB, from which a field-time difference compensation vector is derived. Odd (even) field pels are MC-predicted by the picture at the previous odd (even) field position that is composed of the original previous odd (even) field pels and even (odd) field pels shifted by the field-time difference compensation vector. AVC-195* CODING EFFICIENCY COMPARISON BETWEEN FRAME FORMAT AND FIELD FORMAT (HITACHI) Coding efficiency is compared between three frame-based coding (frame DCT, field DCT, field/frame adaptive DCT) and one field-based coding in an SM3- based coding scheme. Used test sequences are Mobile & Calendar (panning) and Table Tennis (zooming out). It is found that there is small difference among the three frame-based coding and that frame-based coding performs better for Mobile & Calendar but field-based coding performs better for Table Tennis. AVC-196* GUIDING PRINCIPLES FOR THE SINGAPORE MEETING (CCITT EG) Some guidelines are proposed for defining TM0; starting from a very simple scheme for later inclusion of verified elements, room for optimizing low delay mode, core experiment for backward/forward compatibility with MPEG-1 and H.261, room for forward prediction only, scalability and low bit rate operation. AVC-197 SIMULATION OF RANDOM CELL LOSS (UK) A method of simulating cell loss is given, where bitstream specification, cell loss occurrence model, mean cell loss rate and mean burst of consecutive cells lost, programs for cell loss and random number generation are described. Parameter values are proposed for common experiments. AVC-198 CORE EXPERIMENT FOR TESTING B-FRAMES/NO B-FRAMES (NTA) It is proposed to compare "B-frames as in MPEG-1", "low resolution predicted frames in prediction loop", "low resolution predicted frames out of prediction loop", and "prediction based on two previous frames". Experimental conditions are also proposed. AVC-199* A STUDY ON THE EFFECT OF B FRAME (NEC) Comparison of coding efficiency is made between IBP and IP structures, concluding that the former gives better SNR results. AVC-200* A STUDY ON SUBSAMPLING OF CHROMINANCE SIGNALS (NEC) Four chrominance subsample methods to obtain 4:2:0 signals are compared in terms of SNR and subjective impression; line subsampling and repeating/filtered interpolation, filed drop and repeating/filtered interpolation. It is concluded that a method performing no worse than the line subsampling and filtered interpolation is required. AVC-201* SUMMARY OF FUNCTIONALITY PROPOSALS (CHAIRMAN OF MPEG/REQ) Description of functionalities (fast replay, random access, compatibility, low delay mode, scalability, cell loss resilience) is listed which appear in the 30 proposal documents. AVC-202 SELECTION OF TRAFFIC DESCRIPTORS AND THE IMPACT OF BUFFERING (AT&T) Distinction between TD (Traffic Descriptor) and UPC (Usage Parameter Control) is first given. An algorithm to select parameters for TD's (sliding window and leaky bucket) is next provided such that the UPC will find no violations, demonstrating that an additional peak rate constraint is advantageous and that the leaky bucket is a better choice. Furthermore, it is shown that buffering in the video system can reduce the necessary parameters. AVC-203 CONVERSION FILTER FOR PRODUCING SCIF (NTA) A filter is defined to convert from either 525/60 or 625/50 signal to SCIF. Tape demonstration is accompanied. AVC-204* EVALUATION OF SM3 FOR MPEG2 (PTT RESEARCH) It is reminded that the following requirements should be considered for appropriate actions before starting with a modified SM3 as TM0; end to end delay, error protection, adaptation to various storage and transport methods, and compatibility. AVC-205* CELL LOSS EXPERIMENT SPECIFICATIONS (EXPERTS GROUP) This is an update of AVC-197 with some modification in the bitstream specification and parameter values. Temporary Documents TD-1 Agenda for the fifth meeting in Singapore (Chairman) TD-2 Available documents (Chairman) END Documents for the sixth meeting of the Experts Group 18-27 March 1992, Stockholm/Haifa Normal Documents Note: Contributions with "*" have also been sent to MPEG for consideration at the joint sessions. Some documents are also registered directly through the MPEG channel, which are not marked with * but have been considered at the joint sessions. See AVC-257R. AVC-177R REPORT OF THE FOURTH MEETING OF THE EXPERTS GROUP FOR ATM VIDEO CODING IN YOKOSUKA (CHAIRMAN) Achievements and action points obtained at the Kurihama joint sessions and the Yokosuka sole sessions are recorded. AVC-178 REPORT OF SGXVIII MELBOURNE MEETING (SGXV REPRESENTATIVE TO SGXVIII MELBOURNE MEETING - M. BIGGAR) Outcome of the SGXVIII Melbourne meeting is presented focusing on the issues of this Experts Group concern. SGXIIII response to our questions is outlined and further actions which we should take are suggested. It is recommended that any further opportunities for the Experts Group members to attend SGXVIII meetings and vice-versa be exploited. AVC-206R REPORT OF THE FIFTH MEETING OF THE EXPERTS GROUP FOR ATM VIDEO CODING IN SINGAPORE (CHAIRMAN) Achievements and action points obtained at the sole and joint sessions are recorded. This meeting handled mainly those topics related to the source coding algorithm. AVC-207 REPORT OF THE MEETING OF SWP XVIII/8-3 - SERVICES, IVS AND AAL TYPES 1 AND 2 (SWP XVIII/8-3) This report covers the following topics; AAL Type 1, AAL Type 2, liaison to this Experts Group and CMTT/3 regarding AAL Types 1 and 2, service aspects including updating the IVS Baseline Document AVC-208 LIAISON STATEMENTS TO ATM VIDEO CODING EXPERTS GROUP (SGXVIII) The following study results of SGXVIII are contained as responses to the questions sent from the Experts Group; - IVS Baseline Document - AAL for supporting video signal transport - liaison statement to CMTT/3 on AAL for supporting high quality audio signals - use of CLP bit and UPC for peak cell rate - standardization of Network Performance parameter values - G.82X provisional objectives and ATM cell loss AVC-209 IVS BASELINE DOCUMENT (SWP XVIII/8-3 - EDITOR OF IVS BASELINE) This has been updated by incorporating new texts proposed by CCIR IWP 11/9, CMTT/3 and this Experts Group, results of the IVS coordination meeting, and recent achievements in SGXVIII. AVC-210 OUTCOME OF AAL STUDY (SGXVIII) Draft text of section 2/I.363 (AAL Type 1) and possible candidate functions for AAL Type 2. AVC-211 LIAISON STATEMENT TO EXPERTS GROUP FOR ATM VIDEO CODING IN SGXV (WPXVIII/5 - MELBOURNE MEETING) The following items are addressed concerning the multimedia service support on B-ISDN; - interworking user multiplexed signals from N-ISDN with those of VC multiplexed signals in B-ISDN - resource allocation rearrangements during a call - multimedia synchronization Draft I.37y "Network capabilities to support multimedia services" is attached for information and comment. AVC-212* PRELIMINARY WORKING DRAFT - PWD (PWD EDITING GROUP) This document contains a basis of Test Model specifications which has been obtained by the adhoc group established at the Singapore meeting. Some points are indicated as being not clear. AVC-213 FILTERS FOR CONVERSION BETWEEN CCIR-601 AND SCIF (NORWAY) Filter coefficients for converting SCIF back to CCIR-601 signals are given. Tape demonstration for SCIF pictures converted from CCIR-601 sequences and CCIR-601 signals reconstructed are accompanied. This document is supplementary to AVC-203. AVC-214 INTRODUCTION TO AAL TYPE 1 (SPECIAL RAPPORTEUR SWP XVIII/8-3 - K. YAMAZAKI) This document is a collection of tutorial diagrams and explanations to understand the specification of AAL Type 1 and their background. AVC-215 CONSIDERATIONS ON SUPER CIF (BELGIUM, FRG, ITALY FRANCE, THE NETHERLANDS, NORWAY, SWEDEN, UK) Three options (single format, dual format, generic) and their combinations are discussed for the H.26X format specification. Since the development of MPEG-2/H.26X video coding is directed toward a generic standard, it is argued that the selection of a SCIF format will not aid the algorithm development in the way that CIF did for H.261. As a conclusion, the following is proposed; Though a solution which permits world-wide conversational services is needed, the CCITT Experts Group should defer making a firm decision about the incorporation of Super-CIF in H.26X. Study on the topic should continue. AVC-216 THE NETWORK ACCESS FOR MULTI-LAYER AND MULTI-RESOLUTION VIDEO SERVICES OVER THE B-ISDN (UK) Multi-layer coded signals require sufficiently small transmission delay for low bit rate components, differing QOS for different layers, and minimal relative skew timing (or stipulation of maximum value of skew between layers). After discussing three possible scenarios (1 VP with 2VCs having different QOS, 1 VP with 1 VC having CLP bit for multiplexing, 2VPs each with 1 VC), some questions for clarification are placed to the network specialists. AVC-217* PROPOSAL FOR THE JOINT WORK BETWEEN ISO/MPEG AND CCITT/AVC EG (BELGIUM, FRANCE, FRG, ITALY, NORWAY, THE NETHERLANDS, SWEDEN, UK) It is proposed that the meetings of the Video and Requirements groups on matters related to H.26X/MPEG-2 should be held in sequence. AVC-218 A SURVEY ON CBR VERSUS VBR (DBP-TELEKOM) Choice of CBR or VBR is discussed by comparing the five potential codings; CBR, VBR with peak rate regulation where charge may be based on the declared rate or number of transported cells, VBR with peak and average regulation, and 2-layer VBR. Checkpoints are listed for each VBR alternative, stressing the impact of preventive UPC and possible coding efficiency loss of 2-layer schemes. AVC-219 FLEXIBLE SPATIAL RESOLUTIONS (AUSTRALIA) Flexible spatial resolutions, which lie within some maximum resolution limits, is proposed so that a wide range of applications be covered. It is claimed that this approach does not significantly impact on the complexity of codecs and MCUs. AVC-220 FLEXIBLE FRAME RATES (AUSTRALIA) It is proposed to introduce a limited flexibility through frame dropping (as used in H.261) in H.26X. Since the quality requirements of some applications make frame rate conversion unacceptable, it is proposed to consider introducing mechanism to allow a range of frame rates. One simple mechanism to insert explicit source frame timing information in the bitstream is proposed as a starting point of discussion. AVC-221 TRANSPORT OF LAYERED VIDEO ON B-ISDN (AUSTRALIA) The following is pointed out concerning layering of video signals; - to use network capacity efficiently in a layered multipoint video call, multiple virtual channels are required, - layering within an interworking layer, to control the effect of cell loss and match ATM loss priority, should be studied, and - the components within each layer need to be multiplexed in a way that minimizes the impact of cell loss. AVC-222 ATM ADAPTATION LAYER TYPE 2 FUNCTIONALITY (AUSTRALIA) Necessary functions for AAL Type 2 are discussed, raising the following for discussion and communication to SGXVIII; - commonality between AAL Type 2 and AAL type 1 is not required, - aligning video data with cell payload may assist in minimizing error propagation, - cell payload length indicator may be needed to deal with partially filled cells, - sequence number is required to detect cell loss, whose length is to be determined by the B-ISDN cell loss characteristics, - multiplexing capabilities within the AAL may be required to indicate different layers of coded video signal. AVC-223 END TO END SIGNIFICANCE OF THE ATM HEADER CLP BIT (AUSTRALIA) It is proposed that the CLP bit of the ATM header be used only for its intended purpose of cell loss priority indication. Video layer indication is a function which is independent of the CLP bit. AVC-224 NETWORK REQUIREMENTS FOR MULTIMEDIA INTERWORKING (AUSTRALIA) In order to allow smooth migration to the long term goal of VC-base multimedia multiplexing, and to avoid that B-ISDN terminals must emulate 64 kbit/s ISDN user based multiplexing, the following is proposed for liaison to SGXVIII and SGXI; - B-ISDN ISCP signalling and VC-base multiplexing must be able to provide user-user signalling and multimedia multiplexing facilities currently provided by H.221 etc. at a reasonable cost, - network based interworking between B-ISDN and N-ISDN terminals must be provided. AVC-225 DISPLAY FACILITIES (SWEDEN) Information is given about the display facilities during the Stockholm meeting, which can display progressive as well as interlaced pictures. A synthetic test picture is also provided to compare progressive and interlaced displaying. AVC-226 CONSIDERATIONS ON MULTIMEDIA MULTIPLEX METHODS (JAPAN) Multimedia multiplex methods (user/SAR/VCI) are reviewed in the light of AAL Type 1 specification and AAL Type 2 functionality candidates. Then it is pointed out that the multimedia multiplex on one VC should be studied in addition to the reference VCI multiplex method. Finally, MPEG1 system is indicated to have potentially delay and error recovery problems for real time audiovisual communications. AVC-227 REQUIREMENTS FOR TD - TRAFFIC DESCRIPTOR, ESPECIALLY CDV - CELL DELAY VARIATION (JAPAN) After analyzing the terminal configuration with focus on cell delay variation (CDV), the following is proposed as liaison to SGXVIII; - guidance is required for translation between service rated at AAL-SAP and cell rate at ATM-SAP, - CDV of NT2 is the most influential in the terminals system, - definition of CDV should be such that the maximum value is easily calculated at a certain probability, thus the receiving buffer can be designed, - CDV specification should limit the total delay between the two S points so as to meet the requirements of conversational services. AVC-228 CONSIDERATION OF LAN AND MAN (JAPAN) LAN/MAN is characterized by the fact that there is no guarantee when a next video frame signal can be transmitted after the current video frame has been transmitted. Hence commonality between AAL Type 2 and AAL Type 3/4 may become more important in the LAN/MAN environments. AVC-229* STUDY ITEMS FOR EMBEDDED CODING (JAPAN) In addition to coding performance, hardware complexity, end to end delay and service aspects are listed as study items which should be clarified before adopting embedded coding with existing standard core in H.26X. Multipoint communication is discussed as a case involving H.26X and H.261. AVC-230 JITTER PERFORMANCE OF AN ADAPTIVE CLOCK METHOD (JAPAN) Clock recovery experiments are carried out using an adaptive clock method, where PCM video signals with 14.3 MHz (4fsc) sampling frequency are subject to the ATM cell arrival jitter and reproduced pictures are observed by varying the low pass filter characteristics of the VCO loop. It is concluded that the jitter of clock should be reduced to such level as EIA RS-170A standard requires. AVC-231* CODING EFFICIENCY COMPARISON BETWEEN MULTI-FIELD PREDICTION AND ADAPTIVE FRAME/FIELD PREDICTION (JAPAN) Multi-Field prediction and four frame based predictions (combination of adaptive/frame and MC/DCT) are compared in the TM0 framework. It is concluded that adaptive field/frame coding performs better in coding efficiency at the cost of delay and hardware complexity. AVC-232 FIELD ADJUSTED MC FOR FRAME-BASE CODING - 2 - (JAPAN) Prediction efficiency and coded results are reported for the field-time adjusted MC which uses different parity field to get high resolution reference pictures. From these results and analysis on complexity and syntax similarity with MPEG1, it is concluded that this be adopted instead of adaptive field/frame MC. Comparison of multi-field prediction and this technique is also given, supporting the frame base prediction. AVC-233* A STUDY OF LOW DELAY MODE (JAPAN) TM0 simulation is carried out for IBBP, IP'P'P, IPPP and IppP structures (P': non-recursive forward prediction, p: recursive forward prediction with larger stepsizes than those of P). It is concluded that backward prediction improves coding efficiency at the sacrifice of coding delay. AVC-234* SIMULATION RESULTS ON COMPATIBLE CODING (JAPAN) Results of two experiments are reported for the coding efficiency improvements obtained by using base layer pictures as a prediction mode; uncoded CIF pictures in an RM8 based algorithm, and coded SIF pictures in TM0. Consideration of down- and up-sampling filters, field skipping vs field merging is also included to have better prediction from the base layer. It is concluded that the coding efficiency does not deteriorate due to the base layer prediction mode but improvements are necessary for prediction of P and B pictures. AVC-235* CELL LOSS COMPENSATION METHOD (JAPAN) Information is provided on the two experiments addressing cell loss countermeasures; one is on estimation method for a lost motion vector using those of surrounding macroblocks, and the other is on cell loss concealment a) using two vertically adjacent macroblocks, B) cyclic intra pictures (N=12) and C) leaky prediction plus video structured cell in addition to A). The second experiment follows the agreed cell loss experiment specification and method C) is demonstrated to show acceptable picture quality even at CLR=10E-03. AVC-236* COUNTERMEASURES AGAINST CELL LOSS FROM VIEWPOINT OF IMAGE DETERIORATION AND TRANSMISSION EFFICIENCY (JAPAN) Several questions are raised to lead to the choice of cell loss protective measures in H.26X. Discussion is given on the picture quality degradation (spatial and temporal) and synchronization recovery from cell loss focusing on the transmission efficiency. There are also raised questions on cell loss characteristics of the network and necessary compromise between requirements from communication, broadcast and DSM. AVC-237 SIMULATION RESULTS ON HALF PIXEL ACCURACY MOTION ESTIMATION (JAPAN) Half-pel motion compensation is compared between searching in the decoded picture and searching in the original picture using TM0 field based coding. It is concluded that there is little difference in coding efficiency. AVC-238 EVALUATION OF TM0 ALGORITHM AT LOW BIT RATE (JAPAN) TM0 experiments are carried out to test lower bit rate operation. Lower bounds of 1.5 - 2 Mbit/s are found as the limit of normal rate control. AVC-239 PERFORMANCE OF PROGRESSIVE SCIF (JAPAN) Three format conversion methods for 525/60 CCIR-601 and progressive SCIF are compared with respect to picture quality of reconstructed local format as well as SCIF and coding efficiency; intra-field line insertion, adaptive intra-field/inter-field line insertion, intra-field line shift. It is also pointed out that interlace SCIF format may not necessarily be advantageous in coding efficiency. AVC-240 PICTURE FORMAT CONVERSION ACCORDING TO AVC-203 (JAPAN) Frame rate and line number conversion are carried out to obtain progressive scan SCIF pictures according to the filter suggested in AVC-203/213 and another higher order filter. Based on the observation results, it is concluded that distortion due to the current format conversion is larger than the coding noise envisaged for directly coding 525/60 or 625/50 CCIR- 601 pictures at 5-10 Mbit/s. Particularly, frame rate conversion is found to suffer from large area flickers. AVC-241 IMPACT OF SCIF CONVERSION ON PREDICTION STRUCTURE (JAPAN) SCIF pictures converted form 525 line CCIR-601 test sequences using NTA filters (AVC-203) are coded with an RM8 based algorithm. It is shown that single frame prediction suffers significant reduction in coding efficiency compared to multiple frame prediction, pointing out that the definition of coding structure may have to take into account the practical conversion methods. AVC-242 HARDWARE CONSIDERATION ON LINE SCANNING CONVERSION (JAPAN) Comparison of several methods for converting interlace to progressive scan signals are tabulated with respect to camera cost, hardware of scanning converter, hardware size of video codec, coding efficiency and picture quality. It is concluded that the progressive scanning format improves picture quality for only those who have expensive cameras (or complicated scanning converters) and progressive monitors. AVC-243 COMMENTS ON THE PICTURE FORMAT FOR ATM VIDEO CODING (JAPAN) Based on the experimental and other surveys on the impacts of SCIF to picture quality degradation, loss of coding efficiency, increase of delay and hardware/software burden, it is concluded that progressive scan format as proposed in AVC-29 is not promising. It is pointed out that interlace formats my need further study, and that if the SCIF approach cannot give satisfactory solutions, dual format and other approaches should be checked against the above mentioned items. AVC-244 OBJECTIVE EVALUATION SCHEME FOR PICTURE FORMAT CONVERSION (JAPAN) To evaluate the possibility of SCIF, an objective method for comparing format conversion is proposed, which used synthetic test pictures so that exact representation in any format is carried out. AVC-245 TM0 AND IMPROVEMENTS (NORWAY) The following improvements to TM0 are tested and actions in Test Model are suggested; - offset of quantizing decision levels (to be included in TM) - use of decoded pictures for half pixel motion search (to be included in TM) - averaging two fields/frames for prediction (testing to be continued) - adaptive VLC - 3-D VLC (room for further testing to be made) AVC-246 SCIF FORMAT + REQUIRED TESTS (SWEDEN) Based on the reality that progressive cameras and monitors are not widely available now, the purpose of a new coding format is questioned by listing the following three scenarios; - interlaced input/output with intermediate format being always used, - interlaced input/output with intermediate format being used only for interregional communications, - progressive input/output with interlaced input as a temporary solution. Necessary tests including conversion and coding are listed. AVC-247 MONITORING VBR VIDEO TRAFFIC (BELLCORE) After reviewing the current activities of SGXVIII on Usage Parameter Control and Traffic Descriptor, it is pointed out that the codec rate controller and the UPC may monitor the traffic differently, thus some congruency may be needed between the UPC parameters and the codec rate controller parameters. AVC-248 COMMENTS ON THE TABLE FOR MULTIMEDIA MULTIPLEXING METHODS (BELLCORE) It is raised that the following three service attributes be added to the list of requirements; Quality of Service (QOS), Operation and Management (OAM), Cost per VC. AVC-249 CLOCK RECOVERY FOR VIDEO (BELLCORE) SRTS defined by SGXVIII is examined against CBR and VBR video applications which requires recovery of video sampling clock. CBR can use the current specification as it is, but VBR needs some modification in the RTS channel; restricting the minimum information generation, increasing the counting period, or buffering to store RTS temporarily. Collaboration with SGXVIII on this matter is suggested. AVC-250 MERITS OF SQUARE-PEL ASPECT RATIO (AT&T, BELLCORE, DIS, NCS) Currently used pel aspect ratios are listed for such applications as personal computer and workstation, videoconferencing, digital TV broadcasting, HDTV, digital film production and super HDTV. Based on the the fact that computer and film industries require the square pel, and that HDTV follows similar trend, some of its merits are further elaborated. It is concluded that specific parameters close to CCIR-601, such as 704x528 or 768x576, require further study. AVC-251* IMPROVED PREDICTION FOR LOW DELAY VIDEO CODING MODE (FRG - DAIMLER-BENZ) IBBP, IPPP and IP'P'P' structures are compared on SM3 where P' is forward predicted pictures and a prediction mode using weighted interpolation from two preceding coded pictures is added to the preceding frame prediction. IP'P'P' is reported to perform significantly better than IPPP but not better than IBBP. AVC-252* CODING RESULTS FOR SCIF PROGRESSIVE IMAGES (AT&T) Progressive scan signals having 720 pels x 576 lines x 60Hz and obtained from two films were coded according to MPEG1 encoder. Simulation results are presented for coding efficiency comparing the IBP and IP'P structures, VBR traffic descriptor parameters for leaky bucket and sliding window, and impact of cell loss on the one-layer and two-layer transmission. AVC-253 LIST OF REQUIREMENTS FOR VIDEO REQUIREMENTS LISTING (ADHOC GROUP FOR VIDEO REQUIREMENTS LISTING) This is a report of the adhoc group correspondence work, providing a general requirements list for the MPEG Phase 2 video coding standard and a guide for the Video group work. AVC-254* COMPATIBLE CODING STRUCTURE (PTT RESEARCH) A proposal is made for inclusion of a compatible coding structure in the Test Model. The encoder system consists of two loops, an upper loop processing the high resolution image, and a lower loop processing the compatible image. The prediction error in the upper loop is predicted by the coded error signal in the compatible loop. AVC-255* ABOUT THE CONSTRAINTS ON VARIABLE BIT RATE CODING (DBP-TELEKOM) This is an update of AVC-218, including discussion on VBR coding for distribution purposes. Temporary Documents TD-1 Agenda (Chairman) TD-2 Available documents (Chairman) TD-3 Chronicle on the disclosure of patents relevant to px64 (Chairman) TD-4 List of tape demonstrations (Chairman) TD-5 Report of small group meeting on video format (Mr. Morrison) TD-6 Report of small group meeting on network issues (Mr. Biggar) TD-7 Proposal on low delay mode experiments (Mr. Bjoentegaard) TD-8 Draft meeting report for the sole sessions (Chairman) END Annex 1 to Doc. AVC-317R Documents for the seventh meeting of the Experts Group 1-10 July 1992, New Jersey and Rio de Janeiro Normal Documents Note: Contributions with "*" have also been sent to MPEG for consideration at the joint sessions. Some documents are also registered directly through the MPEG channel, which are not marked with * but have been considered at the joint sessions. See AVC-318R. AVC-256R REPORT OF THE SIXTH MEETING OF THE EXPERTS GROUP FOR ATM VIDEO CODING IN STOCKHOLM/HAIFA - PART I (CHAIRMAN) AVC-257R REPORT OF THE SIXTH MEETING OF THE EXPERTS GROUP FOR ATM VIDEO CODING IN STOCKHOLM/HAIFA - PART II (CHAIRMAN) Achievements and action points obtained at the sole sessions in Stockholm and the joint sessions in Haifa are recorded. AVC-258 LIST OF REQUIREMENTS FOR MPEG-2 VIDEO (REQUIREMENTS GROUP) This document lists all the identified requirements for video part of the audiovisual coding, providing definition, application examples and comments, which were updated in Haifa. AVC-259 GUIDE FOR THE VIDEO WORK (REQUIREMENTS GROUP) This document extracts from the general requirements listing only those requirements that directly impact the development of video coding standard and the testing thereof, which were updated in Haifa. AVC-260 TEST MODEL 1 (TEST MODEL EDITING COMMITTEE) A comprehensive description of Test Model 1 (TM1) is given, incorporating coding schemes and various experiments. This model is used in the course of research for comparison purposes. AVC-261 THIRD PROGRESS REPORT (CHAIRMAN) This is a progress report to Working Party XV/1, covering major achievements obtained in the three meetings (Yokosuka, Singapore, Stockholm/Haifa) toward defining Recommendation H.26X "video coding in the ATM environments", and particular items for consideration of WPXV/1. AVC-262 LIAISON STATEMENTS SUBMITTED BY THE EXPERTS GROUP (CHAIRMAN) This is a collection of three liaison statements that the Experts Group sent; two to SGXVIII and one to CCIR Ad-Hoc Group on Digital Coding. AVC-263 MEETING REPORT (WPXV/1) This is a report of the Working Party XV/1 meeting held in Geneva during 7- 13 May 1992. The following items particularly concerns the Experts Group; - Very low bit rate video coding for PSTN and mobile telecommunications, - SGXV endorsement of collaborative work between CCITT EG and MPEG, - Request for inputs on likely applications of B-ISDN, - Handling of MPEG "system" in the framework of AV Recommendations (H.200). AVC-264 RULES FOR PRESENTATION OF CCITT|ISO/IEC COMMON TEXT (CCITT) AVC-265 SOME HELPFUL INFORMATION TO EDITORS OF CCITT/ISO COMMON TEXT (CCITT SECRETARIAT) These two documents provide "presentation rules" for documents which are intended to be both CCITT Recommendations and ISO or ISO/IEC International Standards. These rules are called fictitiously Recommendation A.1000 and ISO/IEC 0001. AVC-266 NETWORK PLANNING FOR VIDEOTELEPHONY & VIDEOCONFERENCE SERVICES (CCITT SGXII) Current status of study is given for the effect of end-to-end delay (transmission and processing delay) on the communication quality. Revised G.114 recommends 400ms as the upper limit of acceptable one way end-to-end delay, recognizing that this limit will be exceeded in some exceptional cases (including videotelephony over satellite circuits). A summary of various evaluation results is also given which addresses the subject in audio only as well as audiovisual communications, indicating that highly interactive tasks require less than 400 ms pure delay (without echo) but that the effects of pure delay on speech quality appears to modestly increase as the delay is increased, hence that further study is necessary. AVC-267 BIT RATE STATISTICS OF A TV DISTRIBUTION CODEC (RTT BELGACOM) Using a hardware hybrid coder (without motion compensation), several VBR statistics are collected for TV programmes in ATM environments; cell inter- arrival times, cell rate for unbuffered packetization, cell rate for slice buffered packetization, and bit rate for image buffered packetization. It is suggested that data may be used for estimating statistical multiplex gain and determining the policing function for TV codecs. AVC-268 MULTIMEDIA MULTIPLEX AND NEGOTIATION METHODS (JAPAN) Three design examples of the interface between the video codec and the media control layer are discussed considering cell loss resilience and H.221 multiplex requirements. Negotiations for the communication mode in B-ISDN, including cases of uni-directional and non-symmetrical transmission, are also discussed from the view point of possible negotiation channels; outband, dedicated channel, inband. AVC-269 SEGMENTATION TRICK TO IMPROVE STRUCTURED PACKING EFFICIENCY OF CODED SIGNALS (JAPAN) An improvement for structured packing method is presented with experimental results where truncation of transmission unit takes place if more than a certain number of cells are already filled and if the remaining capacity of the current cell is less than a certain value. This method provides a better trade-off between transmission efficiency and the size of area damaged by a cell loss. It is noted that the cell packing structure requiring cell boundary information must be standardized, while the segmentation algorithm is not a matter of standardization. AVC-270 CONSIDERATION OF LAN (JAPAN) Difference between B-ISDN and LAN are reviewed with respect to network performance (delay, transmission error, clock). Impact of LAN on H.32X terminals is also discussed. AVC-271 MERIT OF VBR TRANSMISSION (JAPAN) Simulation results are provided which indicate that VBR with sliding window policing of average rate can benefit a coding structure with periodical variation of the coded bit generation like MPEG1. It is shown that the best benefit is obtained if the window size is exactly an integer multiple of coding structure parameter N. AVC-272 IMPROVEMENT OF DELAY UNDER AVERAGE BITRATE CONSTRAINT (JAPAN) Transmission delay is analyzed for CBR and VBR using an information generation model. Sliding window and leaky bucket are compared as average rate UPC methods for VBR assuming the same mechanism is applied to the coder for preventive policing. It is concluded that leaky bucket VBR can provide shorter delay than CBR, but sliding window VBR can not except for a particular case of periodical variation of information generation. AVC-273 CLOCK RECOVERY FOR VIDEO (JAPAN) It is first discussed whether video clock recovery be carried out in AAL or video codec, suggesting that the latter method can be more flexible for multimedia multiplexing. Then, three alternative methods of clock recovery in the video codec are compared; buffer control, stuffing and frequency counting methods. The frequency counting method is suggested from adaptability to VBR services. It is also pointed out that the clock recovery should be studied for the case where a common network clock is not available at both the encoder and the decoder. AVC-274 PICTURE QUALITY COMPARISON OF FORMAT CONVERSION THROUGH / NOT THROUGH SCIF (JAPAN) Conversion between CCIR 625/50 and 525/60 signals is experimented for three different schemes; two schemes use SCIF in the intermediate of conversion and one scheme uses direct conversion. It is concluded that conversions with small delay give similar picture quality regardless of being through or not through SCIF. AVC-275* SCENE CHANGE HANDLING IN LOW DELAY MODE (JAPAN) Scene change which requires a large number of bits per picture and consequently additional buffering delay is discussed with TM experimental results, comparing a strategy which assigns almost constant number of bits per picture and a strategy which allows occasional picture dropping. The second strategy needs definition of skipped pictures in the coder and the decoder. AVC-276* COMPARISON OF PREDICTION METHODS OF THE LOW DELAY MODE OF TM1 (JAPAN) Three experimental results are reported for the TM1 low delay mode; the first experiment compares four frame-based prediction methods indicating FAMC gives the best SNR for M=1, the second experiment compares pure field predictions with frame-based ones indicating that "M=3 pure field" gives better SNR than "M=1 frame/field adaptive", the third experiment shows that half-pel MC referring to the reconstructed pictures gives slightly better SNR than the one referring to original pictures. AVC-277 SIMULATION RESULT ON COMPATIBILITY (JAPAN) Simulation results for the two compatibility experiments are given; "prediction from the base layer" and "prediction for the prediction error". It is concluded that compatible type switching defined in the TM1 syntax is effective for the fist scheme and that the prediction from the base layer provides better performance than the prediction for the prediction error even after having been improved by remaking the prediction from the lower layer depending on the upper layer prediction mode. AVC-278* H.261 COMPATIBILITY REQUIREMENT (JAPAN) After analyzing several H.26X/H.261 interworking scenarios (point-to-point, multipoint, multicast and database access), requirements for the H.26X decoder and coder are concluded as follows; - The decoder in B-ISDN should be able to receive both of H.26X bitstream and H.261 stream, but one at a time, in all the situations including point-to-point, multipoint, multicast and database access. - H.26X encoder should be able to transmit either of H.26X bitstream or H.261 stream at a time for point-to-point communications or multipoint communications where a common operating mode is used or where MCU carries out transcoding. It should also be able to transmit two bit streams simultaneously for multipoint communications where MCU does not provide transcoding or where a mesh connection is employed, multicast communications and in the database. AVC-279* CELL-LOSS COMPENSATION SCHEME (JAPAN) Structured packing (use of macroblock start pointer and absolute block address in the cell header), leaky prediction and concealment at the decoder are simulated for TM1 IP mode (M=1, N=150) and low delay mode, concluding that the scheme is effective, particularly for cell loss sensitive sequences. AVC-280 SIMPLIFICATION OF FAMC (JAPAN) Simplification of FAMC in motion compensation is experimented for address generation and interpolation to show that no or only slight degradation in SNR is incurred. Simplification of motion estimation is also experimented for a two-step search comprising of frame-based ME and FAMC ME. As a conclusion, simplified FAMC43 is proposed for prediction. AVC-281 COMPARISON OF REQUIRED PROCESSING BETWEEN FRAME/FIELD AND FAMC (JAPAN) The number of operations per second is estimated for adaptive field/frame and simplified FAMC as in AVC-280 with respect to addition and multiplication. FAMC requires 60% operations of the adaptive field/frame, but multiplication is involved and maximum memory bus load is doubled. AVC-282 CODING/DECODING DELAY AND REQUIRED MEMORYS FOR THE PREDICTION IN TM1 (JAPAN) Necessary number of field memorys and coding/decoding delay are estimated for the pure field, the frame-based field structure and the frame-based frame structure. AVC-283 HARDWARE VERIFICATION OF H.26X SPECIFICATIONS (JAPAN) Study items to prepare for the hardware verification of H.26X are listed for discussion. It is pointed out that the Experts Group need a policy to cope with those items surrounding the coding algorithm, which are not subjects of verification but required to test H.26X. AVC-284 EXPERIMENT ON LOW DELAY MODE (JAPAN) TM1 low delay mode is first compared with frame-based {N=15, M=1} in coding efficiency, concluding that there is no significant loss of coding efficiency by use of the low delay mode. Then, it is pointed out that the current coding control method for the low delay mode causes visible moving of INTRA slices, proposing a modified coding control method to mitigate the effect. AVC-285 TM1 PURE FIELD CODING SIMULATION RESULTS (PTT RESEARCH - NETHERLANDS) Pure field coding {N=12, M=3} is compared with the adaptive frame/field coding. It is concluded that about equal performance is obtained in picture quality. AVC-286 TM1 PYRAMID CODING AND COMPATIBILITY VERSUS SIMULCAST (PTT RESEARCH - NETHERLANDS) A two layer compatible coding (1.5 Mbit/s for base layer and 2.5 Mbit/s for enhanced layer) as defined in Appendix G of TM1 is compared with simulcast (2.5 Mbit/s). Prediction for the prediction error is used for odd numbered fields of CCIR-601 signals. It is concluded that an obtained gain of 0.5 to 0.7 dB in SNR and other factors (full compatibility, scalability and error resilience) favors this hierarchical structure. AVC-287 ATM CELL LOSS EXPERIMENTS WITH TM1 (PTT RESEARCH - NETHERLANDS) A two layered coding using pure field based coding with upsampled MPEG1 prediction error for odd numbered field prediction error is compared with one layered coding in cell loss resilience. It is concluded that layered coding can be very useful for transmission over ATM-networks when the base layer bitstream can be sent over a guaranteed channel, pointing out that more study and information is necessary for multi-layered coding. AVC-288 ERROR SENSITIVITY OF THE TM1 SYNTAX (PTT RESEARCH - NETHERLANDS) Error sensitivity of TM1 syntax is discussed in resynchronization of bitstream, FEC, forced updating, layered coding, and picture slicing. A specific proposal is made to add two bit identification fields after each extension start code. AVC-289 PSTN VIDEO CODING ON 8 AND 16 KBIT/S USING A DOWN SCALED H.261 (PTT RESEARCH - NETHERLANDS) Simulated and hardware processed pictures are presented which have been obtained using H.261 or its subset (without MC) operating at QCIF, 8-16 kbit/s. It is concluded that a video bitstream conforming to H.261 can be a step towards interworking of PSTN videophone service with ISDN one. It is pointed out that call set up duration, end-to-end delay, spatial and temporal resolution, and interworking between PSTN and ISDN are items of further study. AVC-290 RACE 2072 MOBILE AUDIO VISUAL TERMINAL; PROJECT INFORMATION (PTT RESEARCH - NETHERLANDS) The objectives are to find a powerful audio and video coding algorithm for transmission of moving and still video in a mobile environment and to implement these algorithms on a demonstrator. Technical approach, key issues, expected impact and participants are also presented. AVC-291 LOW-DELAY CODING EXPERIMENT (BELLCORE - USA) Three coding structures are compared in terms of SNR and buffering delay; A(N=15,M=3), B(N=15,M=1), C(N=150,M=1 with forced intra-slices). Simulation results show that low delay mode defined in TM1 reduces the buffering delay by 2 to 3 frames, but at the same time it also degrades the picture quality by as much as 1.84 dB. It is concluded that B and C performs very similarly, but C gives slightly larger buffering delay than B due to that it encodes 28 more intra-slices at the first 15 frames. AVC-292 FREQUENCY SCANNING AND ENTROPY CODING USING MUVLC (HHI - FRG, RTT BELGACOM, SIEMENS GERMANY) In this contribution, UVLC technique is mentioned, an improved version MUVLC concerning coding efficiency is described, a proposed syntax addition to TM1, C-programs for bitstream encoding and decoding a slice of macroblocks, and results on coding gain are given. AVC-293 TM1 COMPATIBILITY EXPERIMENTS (UK) Use of compatible prediction from the base layer is compared with simulcast in TM1 to conclude that it can improve the SNR picture quality. AVC-294 A PROPOSAL FOR AAL TYPE 2 (BELGIUM, GERMANY, ITALY, NETHERLANDS, NORWAY, SWEDEN, UK) Requirements for AAL to support VBR video transport are listed; efficient usage of bits, low delay, extendibility, cell loss detection, bit error protection, compatibility issues, multipoint and multimedia considerations, end-to-end timing and multi-layer synchronization, and interleaving. A generic AAL Type2 and three extensions thereof are proposed to stimulate discussion. It is also pointed out that VBR will most benefit low bit rate video coding in picture quality and delay. AVC-295 ISSUES CONCERNING THE SUPPORT OF FLEXIBLE SPATIAL RESOLUTIONS (AUSTRALIA) Necessary side information and encoder/decoder implementation are discussed for two possible solutions of the flexible spatial resolution approach; to encode the signal as being input and to pad the maximum picture size. It is concluded that the first alternative is more appropriate from the view points of transmission efficiency and effective use of codec processing power. It is also pointed out that a flexible width stripe be adopted to support the flexible spatial resolution approach. AVC-296* CELL LOSS CHARACTERISTICS FOR STATISTICALLY MULTIPLEXED VIDEO SOURCES (AUSTRALIA) Longer term characteristics of cell loss are analyzed for multiplexed VBR sources assuming a simplified time correlation model of of the video sources and a multiplexing process. Average CLR, average congestion time, congestion time distribution and average CLR during congestion are estimated. The results show that bursts of cell loss can last several frames up to tens of frames and that CLR can be of the order of 0.01 during the congestion. AVC-297* THE ATM ADAPTATION LAYER FOR VIDEO SERVICES IN THE B-ISDN (AUSTRALIA) This document gives an overview for the AAL for transport of video services. Methods of multimedia multiplexing are described, presenting features of ATM layer multiplex. Required functions of AAL Type 2 are listed with an example of specific fields. It is also pointed out that cell loss experiments should incorporate some assumptions regarding AAL such as shown in this document. AVC-298* ADAPTING MPEG1 VIDEO FOR ATM TRANSMISSION (AUSTRALIA) Experimental results are provided for transporting MPEG1 coded video over B-ISDN. Use of AAL error detecting functionality, dividing picture types into high and low cell loss priority, and varying the size of slice are addressed. AVC-299 SCALABLE CODING ARCHITECTURE (AUSTRALIA) A scalable encoder architecture is proposed which uses 4x4 DCT for the second layer, 2x2 DCT for the third layer and prediction for the prediction error. This scheme incorporates multiple independent loops to give quality control of all layers and allowing the rate control to be applied to each layer. In order to prevent loss of coding efficiency, independent motion vectors and coding modes for each layer are introduced. It is proposed that the features discussed in this document be included in the scalability core experiments. AVC-300* PROPOSAL FOR CELL LOSS CORE EXPERIMENTS ON LAYERED AND NON-LAYERED CODERS (AUSTRALIA) A proposal is made to define a cell loss core experiment by incorporating short term and long term cell loss characteristics, separation of high and low priority information, reference AAL, use of ATM cell loss priority, use of scalability syntax extension. The aim is to compare non-layered and layered coding structures. AVC-301 FLEXIBLE ENCODER DEFINED PREDICTIONS (NTR - NORWAY) A methodology to unify many prediction modes is proposed whereby the encoder is able to specify and down load predictors. It is characterized as follows; 1) The predictors are not fixed in the standard but may be optimized for each application. 2) The method gives room for almost all the known predictors like frame based, field based and FAMC. 3) It gives room for defining new predictions also after the standard is fixed. 4) The predictors may be down loaded on the sequence level (or picture level). 5) Only one vector is used for each macroblock for P-frames/fields. 6) The implementation complexity is comparable with traditional half- pixel motion prediction. AVC-302 SIMULATION WITH FIELD CODING AND M=1 FOR LOW DELAY (NTR - NORWAY) Simulation results are given for the TM1 low delay mode (field coding) in terms of SNR and buffering delay. The definition of prediction follows the "encoder defined prediction" method proposed in AVC-301. AVC-303 SIMULATIONS WITH VERY LOW BITRATES - (8-16) KB/S (NORWAY) Simulation results are presented for a hybrid DCT scheme operating at 8-16 kbit/s and 32 kbit/s with the picture format QCIF. The average picture frequency of 8-10 Hz is reported. AVC-304 VERY LOW BITRATE VIDEOTELEPHONY STANDARDIZATION (BELGIUM, FRANCE, GERMANY, ITALY, THE NETHERLANDS, NORWAY, SWEDEN, UK) It is claimed that videotelephony service on PSTN and mobile network be initiated to cover all areas of service description, infrastructure, systems, terminals and call control. It is also claimed that video coding algorithm should interwork over various networks. Information on relevant European activities is given. AVC-305 VERY LOW BIT RATE "H.261 LIKE" VIDEO CODING SIMULATION (CNET - FRANCE) Using a picture format of 1/9CIF and H.261 coding scheme with modifications in GOB structure (removal of GOB) and VLC (3-D VLC), simulations were carried out at 8.4 and 16.8 kbit/s. It is concluded that only 5% improvement in coding efficiency is obtained by those modifications and that the picture quality is not acceptable if the size of display is greater than 3-4 inches. AVC-306 TM1 PYRAMID CODING FOR THE SCALABILITY REQUIREMENT (PTT RESEARCH - NETHERLANDS) A proposal is made for a compatible scalable codec structure which uses prediction for the prediction error, pointing out that the structure can be extended for CTV/HDTV compatibility and that it can form a starting point to reach a common solution for the compatibility and scalability requirements. AVC-307* VBR MPEG BIT-RATE CHARACTERISTICS (DAVID SARNOFF - USA) This document provides detailed statistics for VBR operation of MPEG1 coder, which have been collected through simulation of more than 3000 frames of video; 1) frame-by-frame bit rate, probability density function and autocorrelation plots for each test sequence, 2) SNR versus average and peak rates, 3) effect of different peak rate control levels on the image quality, 4) comparison of CBR versus VBR image quality for the same average bit rate. Cell loss resilience and its impact on VBR mode are also discussed. AVC-308* ERROR CONCEALMENT FOR MPEG VIDEO OVER ATM (DAVID SARNOFF -USA) Simulation results for cell loss concealment of MPEG1 coded video are reported where CRC in the transport-level detects cell errors and identify the spatio-temporal position of MPEG slices, replacing errored DCT coefficients with EOB for low priority errors, replacing each errored macroblock with an estimate from the spatio-temporally surrounding macroblocks for high-priority errors (or for one-layer transmission). It is concluded that a reasonable quality of restructured pictures can be obtained on one-tier transmission media with packet/cell loss rate as high as 0.1%. AVC-309 VIDEO TRANSMISSION OVER A RADIO LINK USING H.261 AND DECT (BT - UK) This document describes an adaptation method of H.261 video codec to a radio link. The improved error resilience comprises of FEC, interleaving of the data stream and repeating corrupted blocks. For both of video and radio parts, experimental hardware can be demonstrated. AVC-310 MODIFICATIONS TO TM1 TO SUIT BROADCAST APPLICATIONS (AT&T -USA) Two proposals are made to adapt TM1 to the "tune-in" situation in broadcast applications; inclusion of quantizer matrices in the picture header, and use of leaky prediction where leak factor is transmitted for every P picture in the form of (1-2-n). AVC-311 IVS ACTIVITIES (SWP XVIII/8-3) This document provides a draft agenda for the IVS Technical Session to be held during 26-27 October before the Experts Group meeting. The objectives are to promote further mutual understanding and to achieve an optimized association between networks and coding techniques. AVC-312 LIAISON STATEMENTS (SGXVIII) This collection of liaison statements contain the following items of the Experts Group's concern; possible functions for video signal support of AAL Types 1 and 2, support of H.320 terminals in B-ISDN, traffic control and usage parameter control issues. The second item requires specific answers from the Experts Group. AVC-313 NON-COMPATIBLE VS SIMULCAST VS COMPATIBLE - EXPERIMENT G.3 (BELLCORE - USA) Simulation results are compared between non-compatible at 4 Mbit/s (A), simulcast at 2 Mbit/s (B), compatible at 4 Mbit/s with upscaled prediction from HHR base layer at 2 Mbit/s (C), and HHR at 2 Mbit/s (D). It is concluded that A is preferred over B, perceptual quality of C is not far off from A, some prediction improvements are necessary for P and B pictures, and perceptual difference between B and D is greater than it appears on the SNR values. AVC-314 STATISTICAL ANALYSIS OF VIDEO TELECONFERENCE TRAFFIC - III (BELLCORE - USA) Analyzing a 32,000 frame traffic data produced by a H.261 codec with motion compensation, it is confirmed that the number of cells per frame for video conferences follows a gamma distribution. It is also shown that the density function fits with that of a Markov chain. AVC-315* TIMING RECOVERY FOR VARIABLE BIT-RATE VIDEO ON ATM NETWORKS (AT&T - USA) For the MPEG system (multimedia multiplex), several methods are described to recover timing in video systems where the transmission delay jitter may be substantial as in packetized networks. It is also pointed out that for high quality real time audio and video display, the stability specification of MPEG may not be stringent enough, requiring additional time base correction. AVC-316 RECOMMENDATIONS FOR CELL LOSS EXPERIMENTS (DAVID SARNOFF - USA) Some core experiments are suggested, taking into account codec mode, ATM transport mode, ATM AAL features, ATM network scenarios, and decoder concealment features. Temporary Documents TD-1 Agenda (Chairman) TD-2 Available documents (Chairman) TD-3 List of tape demonstrations (Chairman) TD-4 Generic prediction in AVC-301 (Chairman) TD-5* Report of small group meeting on low delay mode (Mr. Bjoentegaard) TD-6* Report of small group meeting on cell loss resilience (Mr. Biggar) TD-7* Report of small group meeting on H.261 compatibility (Mr. Parke) TD-8 Draft meeting report for the sole sessions (Chairman) END Annex 1 to AVC-355R Documents for the Tarrytwon Meeting (Sep. 28 - Oct. 1, 1992) Normal Documents [ ] indicates MPEG92/???. AVC-317R Report of the seventh meeting in New Jersey and Rio de Janeiro - July 1992, Part 1 (Chairman) AVC-318R Report of the seventh meeting in New Jersey and Rio de Janeiro - July 1992, Part 2 (Chairman) These two documents report the outcome of the previous meeting in New Jersey and Rio de Janeiro. AVC-319 to be considered in Ipswich AVC-320 to be considered in Ipswich AVC-321 to be considered in Ipswich AVC-322 to be considered in Ipswich AVC-323 [N0245] Test Model 2 (Test Model Editing Committee) AVC-326 [413] TM2 Erratum (Test Model Editing Committee) These two documents give specifications for the Test Model algorithm and all agreed experiments. AVC-324 [229rev] Information on requirements for MPEG-2 video (Requirements Group) AVC-325 [230rev] Guide for the video work, Rio revision (Requirements Group) These two documents are the outcome obtained in Rio de Janeiro regarding video requirements. AVC-327 [431] Results of low delay core experiment (Japan) Low delay core experiments are carried out with TM1, mainly adopting FAMC as prediction mode and Frame M=1 as image structure. And the first picture is treated as an intra picture. Through these experiments, it has been confirmed that the techniques of forced intra slice and picture skipping are useful in terms of delay time. AVC-328 [469] Scene change handling without picture skipping in low delay mode (Japan) In order to reduce buffer delay, forced intra slices is a very efficient technique. When scene change takes place, however, temporal or spatial picture quality of the first picture in the new scene is degraded. Picture quality degradation of the coding 'without picture skipping' is considered. The simulation based on TM1 shows that bit allocation for a I-picture influences the picture quality of the I-picture and following P-pictures. However, the influence fades out in about 30ms (10frames). In the worst cases, visual degradation is detected. It is recommended in the low delay coding system without picture skipping that target bits for I-picture should be larger than twice of target bits for P-pictures. AVC-329 [455] Intra slice/column and leaky prediction (Japan) Intra Slice and Intra Column methods are compared, and only a minor difference was found. Leaky prediction method is also studied, and SNR degradation curve for various leaky factor values is obtained using TM2. From the view point of SNR, LF=1-1/16 is concluded as the minimum for sufficient picture quality. AVC-330 [470] Buffering for low delay mode (Japan) This contribution analyzes the buffering problem for the low delay mode (M=1 frame coding and M=2 field coding) where occasional picture dropping takes place to cope with scene changes or other forced update situations. An extension of the existing VBV specifications is proposed to keep the steady state low delay operation by momentarily sacrificing temporal reproduction of the coded pictures. It is also proposed that the headers of dropped pictures are sent with a flag indicating picture dropping and that Temporal Reference (TR) is numbered according to the source picture. AVC-331 [471] Coding efficiency of leaky prediction (Japan) Coding efficiency of the leaky prediction as defined in Core experiment No.6 of TM2 has been measured by an open loop experiment with fixed step sizes. Data for the information generation and macroblock type distribution are provided against the leak factor. Coding loss due to leaky prediction is competitive with the use of periodic intra pictures. Coded pictures are also observed. It is concluded that if we can find a means to remove artifacts peculiar to leaky prediction, such as busy or blocky backgrounds, it will contribute to making the coding algorithm simple and robust, hence generic. AVC-332 [472] Cell-loss compensation scheme (Japan) A cell-loss compensation scheme, which consists of leaky prediction, structured packing and concealment at the decoder, was introduced at the previous meetings. In this paper, the effects of each element, especially leaky prediction, are evaluated in detail through computer simulation for TM2 IP mode and low delay mode. The results indicate that three elements work cooperatively and are effective for cell loss. It is proposed that the standard should provide both the spatial and temporal domain compensation schemes. It is also pointed out that the 8 bit arithmetic accuracy for the leaky prediction can produce residual error of +/- (2**n-1) at maximum for LF=1-1/2**n. AVC-333 [473] Experiments on cell loss resilience (Japan) This document discusses two techniques which should be considered to realize cell loss resilience, i.e. 1) Spatial localization of lost macro block 2) Temporal localization of degraded image For temporal localization, intra picture, intra slice and leaky prediction have been compared. Leaky prediction gives the most favorable impression for the recovery of degraded image, however we have to improve the image quality at the stationary state. AVC-334 [458] Simulation results of compatibility core experiment (Japan) In this document, prediction from the base layer mode and prediction for the prediction error mode were compared again within the TM2 framework. The same tendency as that of the previous document (MPEG 92/257) was obtained. As a conclusion, this document describes that the prediction from the base layer with a switchable compatible type for each field is better than the prediction for the prediction error as a candidate for the compatible mode from the coding efficiency point of view. AVC-335 [474] Proposal of TM2 rate control modification for low delay mode (Japan) The current TM2 rate control for the low delay mode makes the number of bits per picture decreases as time passes by, thus SNR is degraded toward the end of sequence. This document provides two alternative solutions for this problem based on experiments. AVC-336 [475] Picture header modification for source clock recovery (Japan) Modification of picture header to include a new field for video source clock recovery is proposed. Source clock frequency measured with a network clock is transmitted using this field. AVC-337 [432] Simulation results on prediction and DCT mode coupling for S-FAMC (Japan) This document addresses the S-FAMC prediction and DCT mode coupling for inter macro block, which is related to core experiment NO.8 on prediction mode. S-FAMC with frame DCT and with field/frame DCT have been compared and it is concluded that S-FAMC needs the field/frame DCT for rapid motion sequences. AVC-338 [433] Simulation results on S-FAMC and Dual' (Japan) This document addresses Simplified FAMC (S-FAMC) and Dual' prediction, which are core experiment NO.1 and No.3 on prediction modes. S-FAMC defined in TM2 has no interpolation mode for B-picture. However this exclusion of interpolation suffers from loss of coding efficiency. This document proposes the introduction of frame base averaged macro block as interpolation mode of S-FAMC. This introduction makes the coding efficiency high as almost same as original FAMC with keeping memory band width same as field or frame prediction. The field/dual' simulation at 4Mbit/s is also carried out and it is concluded that dual' improves the coding efficiency slightly from field/frame prediction but less than S-FAMC. AVC-339 [456] Simulation results on prediction core experiment (Dual- prime, SFAMC) in TM2 (Toshiba) Performance of the dual prime prediction was evaluated comparing with that of SFAMC. Simulations results shows that both DUAL' and SFAMC similarly improve coding efficiency if they are combined with Frame and or Field. As a conclusion, the dual prime prediction mode is proposed for its high prediction efficiency and its hardware implementation simplicity. AVC-340 [454] Results of low delay core experiments on TM2 - Among prediction modes (KDD) Several prediction schemes are simulated on the low delay mode with M=1, N=15, concluding that; 1) SFAMC with Frame or Field MC gives about 1dB gain in FG, however the gain is limited to about 0.2dB in other sequences. 2) SVMC is effective for both the slow and fast movement and is the best among tested prediction modes in most of all sequences even if its motion calculation load is about 60% of that of Frame/Field MC. 3) DUAL' with Frame and/or Field MC gives better performance than SFAMC with Frame or Field MC in most of all sequences, but less than SVMC especially in BC and CL sequences. AVC-341 [430] Results on the comparison of error prediction versus reconstructed signal prediction (PTT Research) Based on the experimental results showing that there is a small difference (o.o to 0.2 dB) in favor of the prediction from the base layer, it is concluded that the selection should be made according to complexity or functionality. AVC-342 - Short term PSTN videotelephone standardisation (UK, France, Italy, Denmark, FRG, Belgium, The Netherlands, Sweden) Several suggestions are mode toward developing standards, which complement the existing ISDN ones, in a rather short period of time (draft proposal by summer 1993). AVC-343 [488] Results of Core Experiments I.4 - Scalable Side Information (Aus. UVC consortium) This document discusses results obtained within the framework of Core Experiment "Scalable Side Information" whose purpose is to investigate the possibility of reducing the side information on the lowest layer scale_2 in scalable coding schemes. Four coding architectures were experimented in comparison to a single layer TM2 implementation. Results show that a target bit rate of 750 kbit/s at the lowest layer is realizable using scalable side information and appropriate scaling of quantization between the layers. AVC-344 [489] A Frequency Pyramid Architecture with Improved Coding Efficiency (Aus. UVC consortium) A new coding structure is introduced to improve the coding efficiency and to solve the drift problem in frequency scalability schemes. This structure makes use of the prediction from the lower scales by using "path_Y". Experimental results show that this structure improves the coding efficiency of the scalable coder. The following is proposed; - this encoder/decoder structure be investigated as a follow-up experiment for Core Experiment I.2 and I.3, - different bit rate distributions be investigated, - an 8 bit word be transmitted in the sequence header to indicate the structure of the decoder which is necessary in decoding the bitstream. AVC-345 [490] Considerations on ATM cell loss experiments (Aus. UVC consortium) The comparison of the cell loss resilient properties of a spatial layered coded to those of a single layered codec requires careful consideration if a fair comparison is to be made. This document raises important issues and provides Table 1, listing parameters and their values, for spatial layered codec cell loss resilience experiment. AVC-346 [491] Results of Core Experiment I.1 - Interlace-in-Interlace extraction (Aus. UVC consortium) This documents reports on the results of Core Experiment for the interlace- in-interlace extraction. Comparisons are made with a simple upper 4x4 extraction technique both in terms of PSNR and bit rate in each layer. In addition, the effect of using simple extraction on images coded in field mode and adaptive field/frame mode are presented. It is concluded that the Method A extraction technique provides the highest quality reconstructed scale-4 image sequence. It is pointed out that any method of extraction results in a very high rate but only fair quality for the scale-4 service, suggesting the use of a coder and decoder with more than one coding loop. AVC-347 [492] Result of the compatibility experiment 1c : H.261 SIF based prediction of Prediction Error vs Prediction of Input in Frame structure pictures (CNET-FRANCE TELECOM) The base layer is coded by H.261 (RM8). The results show that the compatible coding using the prediction of input outperforms the simulcast. AVC-348 [461] Clarification of Appendix H in TM2 (T. Yukitake) Handling the first picture for "intra picture" case and skipped pictures is proposed to clarify the low delay mode experiment. AVC-349 [493] Leaky prediction: Eliminating the limit cycle (AT&T) The limit cycle problem of the leaky prediction which is caused by finite precision of the digital filter is described. The following two solutions to eliminate the limit cycle are provided; - error spectrum shaping which generates the auxiliary signal using the n least significant bits from the previous truncated signal, - using a pseudo-random auxiliary signal Based on experimental results showing faster convergence, the second solution is recommended. AVC-350 [494] Leaky prediction: Experimental results (AT&T) Leaky prediction was experimented using the second solution described in AVC-349. For five sequences, values of the leak factor which give equivalent quality compared to the case using cyclic I pictures are obtained as 7/8 - 31/32. Then, cell losses are applied to conclude that the leaky prediction gives less visually objectionable pictures. AVC-351 [484] Progress Report for Ad-hoc Group on ATM, Packet Loss and General Error Resilience (Chair, MPEG Ad-hoc Group on ATM, Packet Loss and General Error) An overview is given for the current status of the work, listing various approaches and action points . AVC-352 [495] TM2 compatibility experiments (BT) A two-layered coding scheme is experimented where coded SIF base layer pictures are upsampled and used as a prediction for the CCIR601 layer. A new prediction using the average of upsampled SIF and locally decoded CCIR601 is also experimented. It is concluded that the two layer coding scheme can improve the SNR picture quality over the simulcast approach, and that the new compatibility prediction mode gives subjectively better pictures and warrants further study. AVC-353 [503] Core Experiment I.8 results (BELGACOM, UCL) The aim of Core Experiment I.8 is to compare the efficiency of the frequency scanning method versus the block scanning one. This document collects the first results obtained. It is concluded that; - at this stage of experimentation, both techniques present similar efficiency, - the higher the bit rate, the higher the efficiency of frequency scanning technique, - further studies are required to adapt frequency scanning technique to the context of TM2. AVC-354 [498] Simulation results of the basic TM2 (CNET) This document presents TM2 simulation results for four sequences with statistical data and processed pictures. Temporary Documents TD-1 Agenda for the eighth meeting in Tarrytown (Chairman) TD-2 Available documents (Chairman) TD-3 Review of the Experts Group work plan (Chairman) TD-4 Draft status report - Issue 3 (Chairman) TD-5 Coding structure vs delay in terms of SNR (T. Yukitake) END Annex 1 to AVC-398R Documents for the Ipswich/London meeting (27 October - 6 November 1992) Normal Documents Note - [92/nnn] indicates MPEG92/nnn. AVC-317R REPORT OF THE SEVENTH MEETING IN NEW JERSEY AND RIO DE JANEIRO - PART 1 (CHAIRMAN) AVC-318R REPORT OF THE SEVENTH MEETING IN NEW JERSEY AND RIO DE JANEIRO PART 2 (CHAIRMAN) These two documents report the outcome of the previous meeting in July 1992. AVC-319 I.363 - B-ISDN ATM ADAPTATION LAYER (AAL) SPECIFICATION (SGXVIII) Specifications for AAL Type 1 are provided covering services, interaction with the management and control planes, functions of AAL Type 1, SAR syblayer and CS sublayer. This revision will be approved in March 1993. AVC-320 IVS BASELINE DOCUMENT (SGXVIII) This is a version revised at the June meeting of SGXVIII to align it with other I-series Recommendations and to reflect comments from other groups including this Experts Group. AVC-321 I.371 - TRAFFIC CONTROL AND CONGESTION CONTROL IN B-ISDN (SGXVIII) This Recommendation to be approved in March 1993 contains 1) specifications for traffic description and parameters; definition of peak cell rate, etc. and 2) functions and procedures for traffic control and congestion control; UPC/NPC, priority control and selective cell discard, etc. AVC-322 I.211 - B-ISDN SERVICE ASPECTS (SGXVIII) This Recommendation to be revised in March 1993 contains service classification, general description of network aspects, and video services and coding aspect. AVC-355R REPORT OF THE EIGHTH MEETING IN TARRYTOWN (CHAIRMAN) This meeting report presents the outcome of sole and joint sessions held in September 1992 to elaborate the video Test Model. AVC-356 TEST MODEL 2 - REVISION 2 (TEST MODEL EDITING COMMITTEE) Corrections and clarifications obtained at the Tarrytown meeting were incorporated. AVC-357 STATUS REPORT ON ATM VIDEO CODING STANDARDIZATION, ISSUE 3 [92/576] (EXPERTS GROUP) Study results since September 1991 have been incorporated covering such items as picture format, video coding algorithm, VBR issue, multimedia multiplexing, network aspects, work plan. AVC-358 EFFECT OF PSEUDO-RANDOM SIGNAL INSERTION IN LEAKY PREDICTION [92/577] (JAPAN) The solution for the limit cycle problem proposed in AVC-349 has been evaluated in three independent experiments, concluding that it solves the limit cycle problem without affecting coding efficiency, but "noisy background' still exists and need another fix. AVC-359 SIMULATION RESULTS ON H.261 COMPATIBILITY AND SCIF (JAPAN) [92/578] Compatibility experiments are reported where CIF pictures are used as base layer for coding CCIR601 or SCIF pictures. It is suggested that up-sampling filter characteristics and frame rate of the base layer pictures may largely affect the coding performance. AVC-360 STRUCTURED PACKING (JAPAN) [92/579] Four different proposals regarding the structured packing method are compared in the light of impacts on AAL and video syntax. It is clarified that AAL should support an entry pointer as well as structured data handling, while an absolute addressing mechanism is the requirement for video syntax. It is concluded that further consideration is needed for the best balance among cell loss resilience, AAL/bit stream generality, and coding efficiency. Further study for multiplexed signals is also pointed out. AVC-361 SPATIAL-DOMAIN COMPENSATION FOR CELL LOSS (JAPAN) [92/580] Two methods for spatial localization of cell loss, structured packing and concealment, have been experimented for Flower Garden and Mobile & Calendar at 4 and 9 Mbit/s, concluding that they cooperatively contribute to the cell loss resilience, thus are necessary for sufficient cell loss compensation. AVC-362 PICTURE HEADER OF SKIPPED PICTURES (JAPAN) [92/581] It is proposed to send picture headers for skipped pictures by using a new picture_coding_type "skipped (S)" where there is no slice layer data included. AVC-363 COMPARISON OF PICTURE DROPPING ORDER (JAPAN) [92/582] Based on picture skipping experiments for M=2 field pictures (Core Experiment H.2.5), it is concluded that there is no difference in subjective impression between coding order skipping and display order until the number of skipped pictures becomes 4, thus the former is suggested for its simpler rate control. AVC-364 COMPARISON OF LEAKY PREDICTION AND INTRA SLICE ON CHANNEL HOPPING [92/583] (JAPAN) Four ways of display after channel hopping are demonstrated to evaluate leaky prediction against intra slice; 1) leaky prediction with leak factor of 15/16, 2) blue picture display until a complete picture is refreshed, 3) last decoded picture display until a complete picture is refreshed, 4) blue picture being wiped by each intra slice. AVC-365 HDTV CODING BY TEST MODEL 2 (JAPAN) [92/584] Experimental results are reported for coding of two HDTV sequences with luminance resolution of 1920 pels by 1024 lines at 30, 45 and 60 Mbit/s by applying TM2 straight (M=1, N=60). Observation is made that 30 Mbit/s pictures contain some degradation (mostly granular noise) but 45 and 60 Mbit/s ones are almost free of artifacts. AVC-366 UNDEFINED ITEMS IN COMPATIBILITY CODING (JAPAN) [92/585] It is pointed out that in order to complete the embedded compatibility coding algorithm the following three items should be defined; 1) upsampling filters to generate higher resolution pictures, 2) selection of corresponding lower layer pictures when picture rates are different between higher and lower layers including the case that picture skipping is involved in the lower layer, 3) multiplexing method for the two layer signals. Some discussion is also given to each item. AVC-367 SIMULATION RESULTS ON SPATIO-TEMPORAL WEIGHTING (JAPAN) [92/586] Spatio-temporal weighting has been experimented for compatibility coding to obtain gains of 0.08 dB for Football and 0.25 dB for Flower Garden. Prediction efficiency is improved by this weighting, but the overall coding gain is reduced by the need of transmitting motion vectors for the upper layer as well. Memory bandwidth increase is also pointed out. As a conclusion, it is stated that the current prediction from the base layer is sufficient if total performance is considered. AVC-368 RE-SYNCHRONIZATION BY SLICE SIZE REDUCTION (JAPAN) [92/587] Coding efficiency for the reduced slice size (22, 11, 4, or 2 macroblocks per slice) has been measured to evaluate it as an alternative method for spatial localization of the cell loss to the structured packing. It is reported that picture quality difference is distinguishable between 44 MB/slice and 4 MB/slice, but very small between 44MB/slice and 11 MB/slice. It is suggested that if concealment works well for 11 MB/slice, this method is competitive with the structured packing in performance, thus preferable for its generic nature (i.e. no need for ATM specific solutions). AVC-369 CLARIFICATION OF AAL TYPE 2 (JAPAN) Two AAL alternatives for video signal support are discussed; one allows partially filled cells, the other does not. The former tends to give better transmission efficiency while the latter guarantees the maximum transmission delay. Study items are listed toward defining AAL fields. Difficulty for bit error correction is also pointed out for the latter alternative. AVC-370 MULTIMEDIA MULTIPLEXING METHOD OF AUDIOVISUAL COMMUNICATION (JAPAN) [92/589] Three configurations of the integrated services communication terminal are illustrated to draw attention to the multimedia multiplexing method; 1) multiplexing according to each application specific method at the sending side and multiple demultiplexers at the receiving side, 2) demultiplexing and remultiplexing at the sending side thus single demultiplexer at the receiving side, 3) common multiplexing and demultiplexing across different applications. Some study items are listed for applying the MPEG system as a generic multimedia multiplexing in a communication terminal. AVC-371 VIDEO SOURCE CLOCK RECOVERY (JAPAN) Supplementary discussions are provided for the previous document AVC-336 which proposed a picture header field for transmitting the video source clock information; choice of the video source clock, network clock availability, frequency information transmitting interval, and consideration for retrieval from DSM. AVC-372 VBR CODING UNDER USAGE PARAMETER CONTROL (JAPAN) Measured data of video information generation and leaky bucket fullness are reported for VBR operation of an H.261 real-time hardware, where UPC is given as average rate regulation by a leaky bucket having different sizes. It is concluded that to keep constant quality the bucket size should be of more than several tens of seconds in time while to obtain low delay it can be of several frames in time. AVC-373 SUMMARY OF MULTIMEDIA MULTIPLEXING SYSTEMS (AUSTRALIA) After discussing some items in the comparison table in AVC-129, particularly inclusion of CS multiplexing and benefits of cell-based multiplexing, an updated table is provided. It is proposed to send a new version with further consideration in the Experts Group to SGXVIII for inclusion in the IVS Baseline Document. Conveying the urgency of standardizing the network and signaling support of VC-based multiplexing to SGXI and XVIII is stressed. It is also suggested that the Experts Group should keep the decision of a final multimedia multiplexing method open until the actual cost of VC-based multiplexing becomes clear. AVC-374 CONTRIBUTION TO WORK PLAN (AUSTRALIA) It is suggested that the Experts Group should take a phased approach to the development of the coding standard, taking into account the same approach adopted for the development of B-ISDN standards. A table of work items is provided as a basis for a detailed work program of the Experts Group, listing design component, options, inputs required and impacts. It is proposed that the Experts Group make this detailed work program and advise of the need for appropriate work in other groups, where necessary, to ensure that the overall system is developed. AVC-375 RESULTS ON LAYERED CODER ERROR RESILIENCE (AUSTRALIAN UVC) [92/590] Experimental results are reported for MPEG frequency scalable two layer coder with a single encoding loop in cell loss environments. Three cases are compared in cell loss resilience; two layer coding with cell losses in the upper layer only, the same with cell losses in the base layer as well, an single layer coding, each layer has its own error concealment. It is concluded that the layered coder without lower layer loss performs better than the single layer coder, as does the layered coder with lower layer loss as the overall cell loss ratio exceeds 0.001. AVC-376 THEORETICAL STUDY OF THE USE OF PRIORITY (TELECOM AUSTRALIA) Analysis for SNR performance of predictive coding is given for a statistically multiplexed situation. Particularly cell loss resilient techniques such as leaky prediction and prioritization coupled with layered coding are found useful when the utilization is high. AVC-377 PICTURE FORMATS FOR H.26X (BELGIUM,FRANCE,ITSLY,NORWAY,NETHERLANDS,UK) Due to the lack of information on dominant applications for H.26X, it is proposed that we should take a generic standard approach for H.26X and that CCITT activity should commence when appropriate on "application profiles" which will include picture formats, bit rates and many other parameters. It is also noted that we must make high quality options available for those who need and can afford them, instead of providing only high quality solutions which are above customers' real needs and rejected for cost reasons. AVC-378 VIDEO CLOCK RECOVERY (BELGIUM,FRANCE,ITSLY,NORWAY,NETHERLANDS,UK) Four different methods for the video clock recovery are compared in hardware complexity and functionality; half buffer aim, buffer fill information, signaling encoder video clock frequency, and time stamps. It is concluded to appear that the inclusion in the bit stream of data for the second and fourth methods offers the best route, leaving further study for verifying and extending the scope of the above analysis. AVC-379 SPATIO-TEMPORAL WEIGHTED COMPATIBLE CODING CORE EXPERIMENT (UK) [92/591] Experimental results are presented for the new selected weightings of the base layer prediction and the top layer prediction, reporting that gains of 0.19 dB, 0.12 dB and 0.16 dB have been obtained for P-pictures of Flower, Table and Calendar, respectively. AVC-380 LAYERED CODING CELL LOSS EXPERIMENT (UK) [92/592] Cell loss experiment results are presented for both one-layered simulcast coding and two-layered compatible coding. Video data prioritization is employed; high priority is given to 1) all picture, group and sequence headers as well as all intra picture data of the simulcast signal and the compatible coding upper layer signal, and 2) the compatible base layer signal, while all other dada are set to low priority. It has been shown that cell loss recovery using base layer data is more effective than cell loss recovery using previous picture data, and consequently two-layered coding is more resilient to cell loss than simulcast. AVC-381 CELL LOSS EXPERIMENTS IN LAYERED CODING (PTT RESEARCH-NETHERLANDS) [92/593] Experimental results are presented for a two-layered MPEG-2 pure field coding scheme where concealment techniques based on the full resolution frame memories instead of the MPEG-1 frame memories are employed. It has been shown that the concealment provides a high level of cell loss resilience while the picture quality is not acceptable without use of this concealment. AVC-382 SIMULATION RESULTS OF SPATIAL-TEMPORAL WEIGHTING [92/594] (PTT RESEARCH-NETHERLANDS) Experiments on the spatio-temporal weighting which were carried out according to TM2.1 for field-structure pictures show coding gain of 0.2 dB and more smooth images with less noise than the TM2.1 image. It is also reported that simulation results show a gain in image quality (subjective impression and SNR) for compatible coding compared to simulcast. AVC-383 TERMINAL CAPABILITY SETS FOR MULTIMEDIA SUPPORT (NETHERLADS,UK,FRANCE,ITALY,BELGIUM,SWEDEN,FRG) A notion of "capability set 0" and "capability set x" is introduced to sort out the multimedia multiplexing method issue. The former stands for minimum configuration which every H.32X terminal must offer, thus allows interworking between any level of H.32X terminals, while the latter stands for the maximum configuration which is possible for a H.32X terminal, thus allows use of the cell multiplex method, the SAR multiplex method and the message multiplex method. A lot of capability sets are possible between "capability set 0" and "capability set x", but they all must contain "capability set 0". AVC-384 QUALITY CONSIDERATION ON VIDEO CODING ALGORITHM FOR SHORT TERM [92/595] PSTN VIDEO TELEPHONE STANDARDISATION (NTR) Results from the work in COST211ter shows that significant gain in image quality can be made by changing the prediction of H.261, use of half-pel accuracy motion compensation instead of the loop filter. It is also argued that a new coding algorithm should be close to H.261 with careful consideration of the effect on image quality. AVC-385 CORE EXPERIMENT ON CELL LOSS RESILIENCE BY USING FREQUENCY [92/596] SCANNING (BELGACOM,SIEMENS,HHI) A method of experimentation is given to compare the impacts of cell losses on both the block scanning (basic mode) and the frequency scanning with MUVLC techniques. Global parameters and syntax modifications are described. AVC-386 PROPOSAL FOR GENERAL ONE/TWO TIER MPEG TRANSPORT SYNTAX (DSRC,TCE) This document presents a specific MPEG-2 transport syntax, whose specification is based on a "structured packing" framework with fixed length packets of specifiable size. The protocol consists of three sublayers; 1) network, 2) adaptation, 3) video service. The network layer provides generic service multiplexing, scrambling and priority support for video delivery systems. The video adaptation layer is for efficient packing of variable length MPEG data into fixed length packets, as well as for providing error management facilities. The video service layer is an extension of the MPEG slice header concept, providing decoder resynchronization boundaries in the video bitstream. AVC-387 DISCUSSION OF PRIORITY TRANSPORT OPTION FOR MPEG-2 (DSRC,TCE) This document presents a discussion of how priority processing can be implemented in a practical MPEG-2 system and describes how the bitstreams can be synchronized (or resynchronized after data losses) at the decoder using the priority syntax. Implementation of interfaces between the generic source coding/decoding and transmission media specific prioritizer/VLD, and synchronization of prioritized bitstreams with losses are also discussed. AVC-388 LIAISON LETTER FROM CMTT/2-SRG TO CCITT WPXV/1 EG ACV (CMTT/2-SRG) The updated version of the SRG activity report is brought to the attention of Experts Group. The SRG has been focusing on the CTV/HDTV compatibility. AVC-389 REGULATION SHAPING TECHNIQUE FOR VBR CODEC (FRANCE) A traffic shaping technique consisting of four negotiated parameters (mean bit rate, peak bit rate, timescale during which the bit rate is constant and factor by which the bit rate can be increased or decreased from a timescale to another) has been experimented, using H.261. It is reported that picture quality has been enhanced and the mean bit rate has been preserved during the communications. AVC-390 RESULT OF THE SPATIAL SCALABILITY/COMPATIBILITY EXPERIMENT: H.261 [92/597] BASED SPATIO TEMPORAL WEIGHTED COMPATIBLE MPEG2 CODING (FRANCE) Experimental results are presented for the following four cases; 1) simulcast, 2) full compatible coding without spatio-temporal weighting, 3) spatio-temporal weighted field coding and 4) spatio-temporal weighted frame coding. Bit rates are 1.15 Mbit/s for the base-layer and 2.85 Mbit/s for the upper-layer. It is shown that the fourth compatible mode outperforms the other three compatible approaches with 1 dB gain compared to the simulcast for Flower Garden and Susie. AVC-391 PUBLIC SWITCHED TELEPHONE NETWORK (PSTN) VIDEOPHONE (AT&T) [92/588] Design philosophy and some parameters of a PSTN videophone is given toward standardized videotelephony service, describing video coding algorithm, audio coding algorithm, modem algorithm, communication protocols and data transport services. AVC-392 CORRECTION: ELIMINATING THE LIMIT CYCLE IN LEAKY PREDICTION (AT&T) [92/598] This document provides exact specifications for the limit cycle fix using a pseudo random signal which were proposed at the Tarrytown meeting. AVC-393 EXPERIMENTAL RESULTS WITH LEAKY PREDICTION (AT&T) [92/599] Experimental results are presented on 1) equivalent quality with and without leak, 2) reduction of the noisy background, 3) cell loss resilience, 4) reduction of drift in the frequency scalable sequences, using TM2 frame-based coding with frame-based motion vectors at 4 Mbit/s. AVC-394 TM2 SIMULATIONS AT 4 AND 2 MBIT/S COMPARED WITH MPEG-1 (DAIMLER BENZ - FRG) Experimental results are presented for TM2 coding of the CCIR601 signal at 4 and 2 Mbit/s, and MPEG-1 coding of the SIF signal at 2 Mbit/s. It is concluded that TM2 at 4 Mbit/s is expected to give absolutely acceptable results for a wide area of video storage, exchange and distribution, and that use of SIF for MPEG-1 coding causes significant loss of spatial resolution and heavy motion jerkiness compared to full resolution coding with TM2. AVC-395 HDTV VIDEO CODING USING MPEG2-TM2 (ETRI-KOREA) [92/752] Experimental results are reported for coding of two HDTV sequences with luminance resolution of 1920 pels by 1024 lines at 25 and 35 Mbit/s by applying TM2 straight (M=3, N=15). Observation is made that 25 Mbit/s pictures contain some quality degradation in the "Fashion Show" and granular noise in the "Locomotive" but 35 Mbit/s ones contain few artifacts. It is also pointed out that color sharpness need be improved, e.g. by using 4:2:2 instead of 4:2:0. AVC-396 THE MPEG SYSTEMS SPECIFICATION AND MULTIPLEX [92/549] (S.MACINNIS, G.MORRISON) A broad overview is given to salient general features of the MPEG system which provides 1) decoding and precisely synchronized presentation, 2) multiplexing of 0 to many audio and video streams, 3) a means for coded data buffers in decoders not to overflow nor underflow, 4) decoding after a random access with a reasonable short delay, 5) absolute time identification information for stream(s), 6) very low systems overhead. AVC-397 REPORT OF RAPPORTEUR'S MEETING ON AAL TYPE 5 (SPECIAL RAPPORTEUR SWP XVIII/8-5) An updated text for AAL Type 5 specifications as well as a list of outstanding issues are provided as the output of Rapporteur's meeting held during 19-21 October 1992. Temporary Documents TD-1 Agenda for the sole sessions in Ipswich (Chairman) TD-2 Available documents (Chairman) TD-3 List of tape demonstrations (Chairman) TD-4 Draft response to the liaison from SGXVIII on support of H.320 terminals in B-ISDN (Chairman) TD-5 Review of the Experts Group work plan (Chairman) TD-6 Applications of video coding for B-ISDN (Japan) TD-7 Comments on interworking between PSTN videophones and ISDN videophones (Japan) TD-8 Draft fourth progress report (Chairman) TD-9 Open issues (IVS Technical Session) TD-10 Report from the small group on leaky prediction (G. Bjoentegaard) TD-11 ATM cell loss resilience framework (M. Biggar) TD-12 H.261 compatibility (I. Park) TD-13 Draft liaison statement to SGXVIII on VBR video coding advantage vs UPC time constant (M. Yano) TD-14 Proposed terms of reference for Experts Group for Very Low Bitrate Visual Telephony (G. Eude) TD-15 Draft meeting report for the sole session in Ipswich (Chairman) Annex 1 to AVC-398R Documents for the Torino/Roma meeting (21-29 January 1993) Normal Documents Note - [93/nnn] indicates MPEG93/nnn. AVC-398R REPORT OF THE NINTH MEETING IN IPSWICH and LONDON - PART I (CHAIRMAN) AVC-399R REPORT OF THE NINTH MEETING IN IPSWICH and LONDON - PART II (CHAIRMAN) These two documents report the outcome of the sole and joint sessions held in October and November 1992. AVC-400 TEST MODEL 3 (TEST MODEL EDITING COMMITTEE) AVC-400b TEST MODEL 3 (TEST MODEL EDITING COMMITTEE) [N0328] Achievements and clarification obtained at the London meeting were incorporated into Test Model 3, and several core experiments were defined for action. AVC-401 FOURTH PROGRESS REPORT (CHAIRMAN) This document reports major achievements of the Experts Group toward defining Recommendation H.26X for video coding in the ATM environments, covering three meetings in July, September and October. Three particular items were raised for consideration of WPXV/1; work plan for broadband audiovisual Recommendations, common text approach for H.26X|MPEG-2, and very low bit rate videophone activities. AVC-402 MEETING REPORT - EXCERPT (WPXV/1) Items of the Experts Group concern are extracted from the outcome of the WPXV/1 meeting in November 1992; general SGXV and MPEG relationship, multimedia multiplexing, common text approach for H.26X|MPEG-2, timetable for broadband audiovisual system Recommendations, PSTN videophone, etc. AVC-403 EXPERIMENTS COMPARING LEAKY-PREDICTION AND ERROR CONCEALMENT [93/115] (DSRC) Experimental results are reported for three cell loss concealment techniques (temporal substitution, motion compensated substitution, motion compensated substitution plus I-frame concealment) and leaky prediction (Core Experiment F.3). Slice size of 15 macroblocks is used. It is concluded that leaky prediction degrades picture quality with or without cell losses while decoder only concealment techniques can significantly improve picture quality under cell losses. Channel hopping performance of the leaky prediction is also tested to conclude that annoying artifacts are present even one second after hopping. AVC-404 EXPERIMENTS ON COEFFICIENT SCANNING - F.5 (DSRC) [93/108] Experimental results are reported for two layer transmission of coded data by separating scanned coefficients at some point into High Priority and Low Priority channels. It is concluded that the coefficient scanning approach provides an additional measure of robustness without losing coding efficiency in the no-error case. AVC-405 EXPERIMENTS ON INCREASED ERROR RESILIENCE BY TRANSMITTING I-FRAME [93/116] MOTION VECTORS (DSRC) A syntax change and experimental results are reported for transmitting motion vectors for I-frames and subsequent use of these motion vectors for concealment at the decoder. Experimental results for changing slice sizes at no loss and CLR=10-2 are also included. It is concluded that this technique enables simple yet effective error concealment without impacting system features such as random access and bitstream editing via I frames and with only losing 0.7% of total bitrate. AVC-406 EXPERIMENTS ON STRUCTURED PACKING WITH ERROR CONCEALMENT (DSRC) [93/107] Experimental results are reported for comparison of short slice and structured packing approaches (Core Experiment F.8). It is concluded that using absolute macroblock intervals of 4 results in 0.3 dB loss in the no-error performance but 2.4 dB gain at CLR=10-2 relative to the 22 MB interval. AVC-407 EXPERIMENTS ON SPATIAL SCALABILITY WITH ERROR CONCEALMENT (DSRC) [93/114] Experimental results are reported for cell loss resilience of two-layer spatial scalable coding compared that of non-compatible one. Three different error concealment methods are tested; upsampled substitution, motion vector substitution, mixed (the first for I, the second for P, B) It is concluded that the hierarchical transmission provides more possibilities for error concealment at cell loss rated higher than 10-3 and that the upsampled substitution performs best for error concealment at such high cell loss rates. AVC-408 DEMONSTRATION OF TV AND INTERLACED SIF COMPATIBILITY (UK) [93/002] Compatible coding has been experimented for TV (at 2.5 Mbit/s) and Interlaced SIF (at 1.5 Mbit/s). The results show that TM3 compatible coding is also effective to interlaced pictures in the base layer, that the simplified syntax in MPEG92/651 is valid, and that the two-layered coding is more efficient than the simulcast. AVC-409 COMPATIBLE CODING (UK) [93/004] It is explained how compatible coding is advantageous for manufactures, service providers and consumers and a proposal is made that this approach be applied to the whole range of video coding developments. Out of the three possible compatible arrangements (simulcast, tightly coupled layering, loosely coupled layering), loosely coupled layering is proposed for its more efficient bandwidth usage and more flexibility in coding format and algorithm selection. As an evidence, four layered (QQSIF, QSIF, SIF, CCIR601) coding results are given with those of the simulcast approach, indicating significant difference in picture quality. AVC-410 SNR SCALABLE EXPERIMENT WITH COMPATIBLE SYNTAX (UK) [93/003] Compatible syntax is used for the SNR scalability. Experimental results are given to two schemes; one uses I pictures only for extension, the other uses I/P/B pictures. For a particular case of coding Mob&Cal with 2.5 Mbit/s base layer and 1.5 Mbit/s enhancement, 1 dB and 0.66 dB gains were obtained for the I/P/B and I only enhancements, respectively, compared to simulcast. AVC-411 SIMULATION RESULTS ON COMPATIBILITY (JAPAN) [93/015] Simulation results show that gain of embedded coding for the interlace-interlace case is smaller than that for the interlace-progressive case. The sophisticated upsampling filter in MPEG92/758 does not improve coding efficiency, but intra quantization for compatible macroblocks provides more improvement. Based on the coding efficiency comparison between spatio-temporal weighting and simple prediction from the base layer, it is proposed not to include the spatio-temporal weighting in the syntax taking its hardware complexity into account. AVC-412 COMPARISON BETWEEN SHORT-SLICE METHOD AND STRUCTURED PACKING [93/079] (JAPAN) Experimental results and numerical evaluations are given for the comparison between the short slice method and the structured packing method, which are defined in Core Experiment F.8. Considering the small difference in SNR and subjective quality, short slice is recommended since it does not need syntactic changes. Experimental results for concealment and leaky prediction combined with short slice or structured packing are also given. Evaluation of re-synchronization period by observation of processed pictures is described as 4 macroblocks being sometimes insufficient, requiring further study on applications, picture size, etc. AVC-413 REPORT OF AC-LEAKY PREDICTION (JAPAN) [93/158] Experimental results are reported for Core Experiment F.7 "AC-leaky prediction", stating that DC refresh once every 6 frames gives the same coding efficiency as N=15 non-leaky prediction without limit cycle problem or noisy background. AVC-414 FIX FOR THE NOISY BACKGROUND PROBLEM IN LEAKY PREDICTION (JAPAN) [93/080] Experimental results for adaptive DC quantization in leaky prediction (Core Experiment F.3) are reported, concluding that the noisy background is significantly improved thus the leaky prediction is a desirable method of temporal localization of errors. Fixed step size of 8 is applied to DC components if a macroblock is identified as belonging to background according to the value of N_act defined in the TM3 rate control Step 3. Use of adaptive quantizer weighting matrix is suggested for this purpose. AVC-415 RESULTS ON NON-8X8 DCT CORE EXPERIMENTS (Q.5) IN LOW DELAY [93/083] MODE(JAPAN) Experimental results for the adaptive 8x1/8x8 DCT defined as Core Experiment Q.5 are reported, concluding that application of this technique is effective for the low delay operation in reducing mosquito noise, that adaptation based on absolute value summation of DCT coefficients is effective, and that the syntax can be simplified without significant loss of coding efficiency. AVC-416 CASCADE CODING OF H.26X AND H.261 (JAPAN) [93/081] Cascade coding of TM2 (CCIR 601-525 format) at 4 Mbit/s and RM8 (CIF) at 1.5 Mbit/s, 384 kbit/s and 64 kbit/s has been experimented for Flower Garden to find that coding performance in terms of SNR and subjective quality does not differ from that of direct RM8 coding. It is concluded that transcoding is a possible means of compatibility between H.26X and H.261. AVC-417 CLARIFICATION OF LOW DELAY DESCRIPTIONS (JAPAN) [93/084] The following clarification is proposed for the syntax and semantics of the skipped picture (S-picture); - decoder operation, - value of the vbv_delay field to be set at the encoder and its use at the decoder, - data removing timing in VBV. AVC-418 CORE PROFILE BASED ON COMMUNICATION APPLICATIONS CONSIDERATION [93/082] (JAPAN) Attributes and their values of the core profile is proposed in terms of TM3 syntax elements. The approach taken here is first to select necessary elements for each of five typical audiovisual communication services on B-ISDN, and then to decide core profile elements considering those selection results and the fact that the core profile should cover other non-communicational services as well. Some items are left for further study; compatibility/spatial scalability, chroma format, special prediction, non 8x8 DCT/NTC. Influence of Cable TV on chroma format and special prediction is mentioned because of its demand size. AVC-419 USE OF COMPATIBILITY/SPATIAL SCALABILITY IN MULTIPOINT AUDIOVISUAL COMMUNICATION SYSTEMS (JAPAN) Analysis is given to a multipoint communication system where H.32X terminals (containing H.26X) and H.320 terminals (containing H.261) are involved. Three configurations (embedded, simulcast, switchable) are compared in terms of qualitative order for picture quality, delay, complexity of terminal and MCU. It is concluded that video coding for H.32X should be switchable between H.26X and H.261, and if the transcoding approach for multipoint communications is not appropriate it should further support embedded or simulcast as a mandatory or optional specification. Some items are listed for further study; bit rates, implementation complexity, multimedia multiplexing. AVC-420 DEMONSTRATION OF HDTV CODING BY D1 VCR (JAPAN) [93/014] A part of TM2 coded HDTV pictures (presented in AVC-365) is demonstrated by using D1, where two sequences coded at 30/45/60 Mbit/s are contained. AVC-421 MODIFICATION OF THE CCITT/MPEG ATM CELL LOSS MODEL [93/159] (NL, UK, I, F, N, B, FRG) In this document, it is pointed out that the characteristics of the random generator also influence the simulation of cell loss when cells of only one priority are used. A modification to the cell loss model is proposed to improve the simulation of cell loss. AVC-422 ADDING COMPATIBLE PREDICTION TO EVEN FIELDS (PTT RESEARCH) [93/048] Experimental results are reported for adding compatible prediction to even fields from the odd field base layer in a field picture compatible scheme, concluding that this addition does not affect the performance in SNR and subjective quality. AVC-423 INTERLACE TO INTERLACE CONVERSION (PTT RESEARCH) [93/0049] Experimental results are given for the maximum gain obtainable with interlace-interlace compatible coding and for impacts of horizontal upconversion filters. It is concluded that the maximum gain by use of the non-coded base layer picture is 0.5 - 0.8 dB and that short and long horizontal filters presents no significant difference in SNR performance. AVC-424 RESULTS OF FREQUENCY SCALABLE CODEC ERROR RESILIENCE EXPERIMENTS [93/122] (AUSTRALIAN UVC CONSORTIUM) Cell loss experimental results are reported for the following four schemes; - single layered coding, - simple frequency scalable coding using scale_8 and scale_4 layered with no errors in scale_4, - the same with CLR=0.001 in scale_4, - the same with equal errors in scale_4 and scale_8. It is concluded that the simple frequency scalable coding performed well with respect to cell loss resilience. AVC-425 PROPOSED FRAMEWORK FOR ERROR RESILIENCE INFORMATIVE TEXT IN [93/016] MPEG2/H.26X (AUSTRALIAN UVC CONSORTIUM) A framework of informative text for the error/cell loss resilience is proposed for consideration and refinement. It consists of general description of error/cell loss environments and possible techniques to cope with them; concealment, spatial localization, temporal localization, layered coding. AVC-426 ERROR RESILIENCE AND FREQUENCY SCALABLE CODING [93/017] (AUSTRALIAN UVC CONSORTIUM) Advantages of the frequency scalable coding are discussed with respect to increased cell loss resilience, obtained by allocating most important DCT coefficients to a guaranteed channel, and by-product of some scalability features. It is proposed that an error resilience method with scalable extensions be considered for the MPEG-2 core and that converging this technique with "Coefficients Scanning" in Core Experiment F.5 be merged to add additional functionality. AVC-427 SPATIAL LOCALISATION FOR CELL LOSS RESILIENCE [93/018] (AUSTRALIAN UVC CONSORTIUM) Experimental results are reported regarding the number of lost macroblocks per lost cell for four different AAL packetization schemes; combination of whether AAL is streaming mode or message mode and whether macroblock resynchronization is used or not. It is summarized that the number of macroblocks per lost cell is roughly half of the slice size for the case without macroblock resynchronization, and that it reduces to 1/3 to 1/10 for the case with macroblock resynchronization regardless of the AAL packetization scheme if the slice size is not smaller than 22, and that if the slice size is shortened message mode with macroblock resynchronization becomes overly inefficient due to overhead of unused cell capacity. AVC-428 A HYBRID AAL PACKING SCHEME (AUSTRALIAN UVC CONSORTIUM) [93/019] A new AAL packing scheme is presented which combines features from the structured packing and the short slice size method; the first macroblock in every cell is made the first macroblock of a slice. AAL has 1 bit of "Slice Start Present" and 9 bits of "Slice Start POSition" to indicate the start of the slice, the encoder taking into account where the cell boundary is. It is shown that coding efficiency and performance under cell loss condition is very comparable to that of the structured packing approach. AVC-429 DEMONSTRATION OF COMPATIBILITY WITH H.261 (UK) [93/005] Experimental results are reported for a loosely coupled 'spatial split' scheme using H.261 coded 30 Hz CIF at the base layer and TM3 coded 25 Hz CCIR601 at the upper layer. Bit rates are 0.5 Mbit/s for the base layer and 2 Mbit/s in total. It is concluded that the 'spatial split' from TM3 provides the possibility of compatible layered coding with such combination, but that requirements of the general upsampling process needs further study. It is pointed out that temporal imperfections of up- and down-sampling process have an effect on the performance of the compatible prediction, suggesting motion compensated interpolation. AVC-430 ON THE CHARACTERIZATION OF THE CELL LOSS PROCESS OF VBR MPEG ON [93/???] ATM (DSRC) Simulation results for average burst length and average inter burst length are presented for a wide range of network utilization by modeled VBR MPEG-1 video traffic (average bit rate = 5.4 Mbit/s, average peak/average ration = 4, average SNR = 31dB). AVC-431 LEAKY PREDICTION (TELIA RESEARCH) [93/076] Experimental results are reported for leaky prediction with limit cycle solutions 1 and 2 in TM3 with adaptive macroblock quantization, concluding that the two solutions present no difference in SNR performance. It is also reported that leaky prediction for Mob&Cal produces quite noisy background. AVC-432 CELL LOSS ON ONE LAYER CODING (TELIA RESEARCH) [93/0077] Decoding strategies for transmission errors (cell losses in particular) are first discussed for cases with and without error detection, two possible ways when an unused VLC codeword is encountered, and two possible ways to process undecoded area lying between a discovered error and a next start code. Simulations results are also presented to compare these to conclude that cell loss detection is preferable, that undecoded areas should be carefully reconstructed, and that for panning scenes use of the last correctly received motion vector is effective but further study is necessary for intelligent prediction frame store for other type of scenes. AVC-433 SPATIAL SCALABILITY, INTERLACED TO INTERLACED (TELIA RESEARCH) [93/078] Experimental results are reported for compatible coding of Mob&Cal using interlace-interlace scalability, concluding that the best spatio-temporal weight is (w1,w2)=(0.25,0.25) and that simple spatial filters are not useful. AVC-434 SIMULATION RESULTS ON DTV AND HDTV COMPATIBILITY (ETRI) [93/160] Experimental results are reported for embedded coding of HDTV (1920x1024 Y-pels per picture) and DTV (960x512 Y-pels per picture). The coding scheme is a spatial pyramidal one which uses TM2 for both layers, assigning 15 Mbit/s to DTV and additional 20 Mbit/s to HDTV. AVC-435 LIAISON STATEMENTS SENT TO SGXVIII (CHAIRMAN) This document contains the following three liaison statements sent to SGXVIII from the Experts Group; - support of H.320 terminals in B-ISDN, - VBR video coding advantage vs UPC time constant, - update of the multimedia multiplex summary table in IVS Baseline Document. AVC-436 LIST OF OPEN ISSUES (CHAIRMAN) Open issues are listed with description of options, status, input required. aimed Recommendation, applications and target date according to the following categories; - framework for video coding standardization, - picture format, - video coding, - VBR vs CBR, - interface with networks, - end-to-end signalling, - multipoint communication system, - B-N interworking, - audio coding. Background information such as system configuration, applications, milestones and target date (priority) is also contained. AVC-437 NEW WORK ITEM ON H.320 ADAPTATION TO ATM (F,UK,B,I,N,G,NL) It is stated that ETSI/NA5/VCM members agree to include a new work item on adaptation (or extension) of existing H.320 terminals to ATM environments in the studies of the Experts Group. The target date to complete this Recommendation should be 1994. AVC-438 CLARIFICATION ON PROFILES (F,UK,B,I,N,G,NL) [93/154] This paper is a discussion paper that first lists some questions for clarification on profiles. It then describes two profiles as a basis for discussion: Telecom profiles for conversational applications and Telecom profile for retrieval services. AVC-439 EXPERIMENT ON SPATIO-TEMPORAL WEIGHTED H.261/MPEG2 COMPATIBILITY [93/106] WITH BASE LAYER AT 128/384 KBIT/S (FRANCE) This paper present the results of a (core) experiment about H.261/H.26X compatibility by using a two layered prediction scheme with base layer at 128/384 kbit/s with subsampling. It also includes a combination of MC based temporal prediction from top layer with a spatial prediction from base layer. AVC-440 SPECIFICATION OF UPSAMPLING FILTERS FOR HIERARCHICAL CODING IN H.26X/MPEG-2 (UK) A question is raised whether the upsampling filters in the encoder and decoder must be identical in arithmetic processing. A possible alternative approach of defining an ideal target filter and tolerable deviation from it is discussed to encourage consideration and study of this approach. AVC-441 PROPOSALS FOR AND DISCUSSION ON THE SYNTAX TO EXPLOIT THE [93/179] CORRELATION BETWEEN SIMILAR VIDEO SIGNALS OVER A PAIR OF VIDEO CODECS (PTT RESEARCH) Based on considerations of several embedded coding applications, this document proposes to include a 2 bit interlaced indication code in the sequence header and a stream_id codeword in the if(embedded) {...} section. Renaming of sscalable to embedded, replacing sscalable_code by a 3 bit ssr code and adding a note to clarifying ssr referring to frame pictures are also proposed. AVC-442 RESULTS OF EXPERIMENTS ON LEAKY PREDICTION (AT&T) [93/178] This document present views on the leaky prediction, summarizing that it ought to be included in the MPEG-2 core bitstream. It is also mentioned that impairments are much less visible with 60Hz, progressively scanned pictures. Temporary Documents TD-1 Agenda for the sole sessions in Torino (Chairman) TD-2 Available documents (Chairman) TD-3 List of tape demonstrations (Chairman) TD-4 Noise in leaky prediction (Chairman) TD-5 Excerpt from "Guide for CCITT and ISO/IEC JTC1 Cooperation" TD-6 Proposed CCITT EG positions for items requiring decision (Japan) TD-7 Error resilience framework for informative text and experimentation (CCITT EG) TD-8 Draft meeting report (Chairman) END Annex 1 to AVC-496R A1.1 Documents for the sole sessions in Melbourne Normal Documents AVC number MPEG93/... Pur- pose Title (source) AVC-443R 414 R REPORT OF THE NINTH MEETING IN TORINO and ROMA - PARTS I,II (CHAIRMAN) AVC-444R 414 R REPORT OF THE NINTH MEETING IN TORINO and ROMA - PART III (CHAIRMAN) AVC-445b 225b R Test Model 4 (Test Model Editing Committee) AVC-446 92/ 091 R MPEG-2 Working Draft - Video Part - Version 1, Revision 2 (Working Draft Editing Committee) AVC-447 - R Liaison statements (SGXVIII) AVC-448 - R IVS Baseline Document (D. Dorman, Editor) AVC-449 423 R MPEG-2 Working Draft - Video Part - Version 3 (Working Draft Editing Committee) AVC-450 404 P Selecting rule of reference pictures in the low delay mode (Japan) AVC-451 403 P Clarifications of VBV operation (Japan) AVC-452 396 P/D Syntax modification for VBR operation (Japan) AVC-453 401 I Report of non-8x8 DCT experiment (Japan) AVC-454 402 I Report of AC-leaky prediction (Japan) AVC-455 - I Fix for the noisy background problem in leaky prediction(Japan) AVC-456 398 I Experiment on leaky prediction (Japan) AVC-457 405 I Experiments on data partitioning by PBP (Japan) AVC-458 397 I Experiments on error concealment with Data Partitioning (Japan) AVC-459 - D A study on forward error correction method in AAL Type 1 (Japan) AVC-460 387 I Quantization of Intra-compatible MBs (Japan) AVC-461 399 P Up-sampling methods for spatial scalability (Japan) AVC-462 - I VBR coding under Usage Parameter Control (Part 2) (Japan) AVC-463 406 D Consideration of MPEG-1 Systems as multimedia multiplexing for audiovisual communications (Japan) AVC-464 407 I/D Relation between MPEG-2 transport mux and ATM/AAL (Japan) AVC-465 408 P Video source clock recovery using network clock (Japan) AVC-466 252 D Preliminary DSM control command requirements (PTT Research - NL) AVC-467 253 D Interworking and complexity requirements on scalable video coding algorithms (PTT Research - NL) AVC-468 255 D System multiplexing and priorities (PTT Research - NL) AVC-469 254 I Stereoscopic video transmission: a future application of spatial embedded coding (PTT Research - NL) AVC-470 - P MPEG-2 syntax (F, UK, B, I, N, D, NL, CH) AVC-471 394 I Variable slice sizes vs small fixed slice sizes (Australia) AVC-472 395 I Cell loss resilience of data partitioning (Australia) AVC-473 327 I/P Report of Ad-hoc Group on ATM Cell Loss Error Resilience (Australia) AVC-474 342 P Bitsavings on the prediction_weigth_code (BT, PTT Research) AVC-475 368 D MPEG Systems and B-ISDN (Australia) AVC-476 369 D Data Partitioning and the Main Profile" (Australia) AVC-477 370 D Layered coding informative text (Australia) AVC-478 367 I Effectiveness of Data Extraction for Interlaced Source Material (Australia) AVC-479 314 I Evaluation of Scalable Coding Schemes (Australia) AVC-480 371 I Quantization of spatially scalable prediction errors (BT) AVC-481 372 D/P The use of MPEG-2/H.26x for low bit rate applications (BT) AVC-482 373 D Enhancement of spatial scalability for reduced cost decoders (BT) AVC-483 321 D/P Sequence Layer Syntax (BT) AVC-484 - D List of open issues, Version 2 (Chairman) AVC-485 366 Experimental results with AC leaky prediction (AT&T) AVC-486 433 D Harmonising/combining low complexity, error resilience, scalability, image quality and compatibility (PTT Research) AVC-487 - D CCITT patent policy and MPEG-2 patent status (Siemens AG) AVC-488 383 D Results on TM4 prediction Core Experiment on mod. SVMC-Prime (Tektronix) AVC-489 297 I Some results on Frequency scalability Experiments I.4 (Tektronix) AVC-490 459 D H.26X error resiliency based on data partitioning and concealment (Tektronix) AVC-491 457 R Test Model 5 (Test Model Editing Committee) AVC-492 R Revised syntax and semantics for MPEG-2 video (Video syntax sub-group) AVC-493 R MPEG-2 Systems Working Draft (Systems Committee) AVC-494 I Simulation results on CTV/HDTV compatible coding (ETRI) AVC-495 483 I Multi-channel information carried by Systems layer (Australian UVC, IBM, Tektronix) Temporary Documents TD-1 Chairman Agenda for the sole sessions in Melbourne TD-2 Chairman Available documents for the Sydney/Melbourne meeting TD-3 Chairman List of tape demonstrations TD-4 Chairman Audiovisual communication system using a spatially scalable bitstream TD-5 Chairman Audiovisual communication system using a frequency scalable bitstream TD-6 Chairman Report of regional coordination meeting TD-7 Requirements sub-group Profile architecture TD-8 WTSC-93 New structure of the ITU TD-9 C. J. McGrath MPEG-2 Systems meeting in Sydney TD-10 G. Bjoentegaard VBV operation to take care of skipped pictures TD-11 G. Morrison Support aspects required for "Layered" video coding algorithms TD-12 A. Tabatabai, T. Sikora Comparison table TD-13 Chairman Memorandum on agreements TD-14 A. Koster Systems video 'Relation' stream (MPEG93/451) TD-15 S. Dunstan MPEG Systems outline TD-16 Syntax editing team Sequence layer syntax in WD Abstracts for AVC-numbered documents AVC-443R REPORT OF THE TENTH MEETING IN TORINO and ROMA - PARTS I and II (CHAIRMAN) AVC-444R REPORT OF THE TENTH MEETING IN TORINO and ROMA - PART III (CHAIRMAN) These two documents report the outcome of the sole and joint sessions held in January 1993. AVC-445b Test Model 4 (Test Model Editing Committee) Achievements and clarification obtained at the Roma meeting were incorporated into Test Model 4, and several core experiments were defined for action. AVC-446 MPEG-2 Working Draft - Video Part - Version 1, Revision 2 (Working Draft Editing Committee) AVC-449 MPEG-2 Working Draft - Video Part - Version 3 (Working Draft Editing Committee) Working Draft is a document which should evolve into Committee Draft in November 1993. This video part is substantially structured as follows; - Profiles and levels - Video bitstream syntax and semantics - The video decoding process - Defined profiles and levels AVC-447 Liaison statements (SGXVIII) Three liaison statements we re generated at the January 1993 meeting of SGXVIII (now ITU-TSS SG13) regarding the following items; - Update of the IVS Baseline Document - Request of information on maximum allowable AAL delay for supporting H.320 terminals in B-ISDN by introducing a forward error correction in AAL Type 1. - Traffic parameters for average cell rates, particularly measuring time constants of seconds or more - Interworking issues when using CLP bit and resource allocation options AVC-448 IVS Baseline Document (D. Dorman, Editor) This is a version revised at the January 1993 meeting of the Working Parties of SGXVIII (now ITU-TSS SG13) to incorporate inputs from other groups and SGXVIII achievements. The principal amendments include: - revision of standardization time tables for SGXVIII, SGXV, TG CMTT/2, - revision of summary table for multimedia multiplex methods, - updated and prioritized open issues list for multimedia Recommendation I.374, - inclusion of possible functions for video signal support of AAL Type 1 and Type 2, - list of open issued generated at the IVS Technical Session in October 1992. AVC-450 Selecting rule of reference pictures in the low delay mode (Japan) Taking into account of the case to use skipped pictures, a consistent rule of selecting reference pictures is proposed for forward and backward prediction in Frame pictures and Field pictures. Forward prediction refers to the latest available coded picture(s) while backward prediction refers to the latest coded picture, if it exists, which follows the current picture in the source order but precedes in the coding order AVC-451 Clarifications of VBV operation (Japan) This document first clarifies VBV related items when picture skipping is involved and then usage of the vbv_delay and VBV operation are specified. Encoding operation and setting of vbv_delay are also described which satisfy the VBV specifications. Modified description for "Video Buffer Verifier" and "Low Delay Coding" in WD is provided. AVC-452 Syntax modification for VBR operation (Japan) In order to acommodate VBR in the Main Profile, this document proposes extension of bit_rate filed to vbr_mode (1 bit), bit_rate (18 bits) and ave_rate (18 bits) and extension of vbv_buffer_size to 16 bits. How to set vbv_delay in VBR operation is also discussed concluding that further study is required. AVC-453 Report of non-8x8 DCT experiment (Japan) Experimental results are reported which indicate that 8x8/8x1 DCT improves field-picture coding and frame-picture coding by 0.47-0.75 dB and 0.22-0.40 dB, respectively. It is also reported that if 8x8/8x1 DCT is used, further use of Frame/Field DCT gives only 0.02-0.31 dB improvements. AVC-454 Report of AC-leaky prediction (Japan) Experimental results for AC-leaky prediction and more frequent intra DC refresh are given to show that the technique is efficient and effective for temporal localization of errors. AVC-455 Fix for the noisy background problem in leaky prediction(Japan) Experimental results are reported that a combination of periodic stronger leak and adaptive MB quantization for background areas give SNR performance and subjective quality very close to the intra slice method. AVC-456 Experiment on leaky prediction (Japan) Experimental results are reported on comparison between TM3, AC-leaky prediction and Adaptive DC quantization, concluding that both of the leaky prediction methods could not achieve as good picture quality as that of TM3 at 4 Mbit/s due to remaining background noise. AVC-457 Experiments on data partitioning by PBP (Japan) Experimental results are reported on reconstructing pictures only from the base layer information partitioned by PBP, concluding that adequate quality for practical use can not be obtained due to accumulation of mismatch errors even if the intra slice updating is used. AVC-458 Experiments on error concealment with Data Partitioning (Japan) Experimental results are reported on error concealment in the two layer partition by PBP (base and additional bitstreams) when cell loss takes place only in the additional stream. It is concluded that simple error concealment provide sufficient error resilience for PBP value 0 inter macroblocks. For intra macroblocks, more coefficients needed to be transmitted via the high priority channel for which suggested changes in the PBP semantics are given. AVC-459 A study on forward error correction method in AAL Type 1 (Japan) Application of RD(48,44) code to AAL Type 1 is considered for cell loss correction and random eerror correction in a cell. This FEC provides for transmission efficiency of 91.5% and error correction processing delay of 32 ms at 384 kbit/s. AVC-460 Quantization of Intra-compatible MBs (Japan) Experimental results are reported on applying intra quantization to intra-compatible macroblocks for both interlace-interlace and interlace-progressive cases. Though 0.6-0.87 dB gain is obtained for I pictures with this method, improvements at the total sequence is not so large as to justify such change from the current quantization. AVC-461 Up-sampling methods for spatial scalability (Japan) Three methods of specifying upsampling filters for spatial scalability are discussed; 1) specifying unique set of filters, 2) downloading the coefficients from encoder to decoder, 3) tolerating filter coefficient mismatch between encoder and decoder. In the interest of hardware overload, the second method is concluded as undesirable. AVC-462 VBR coding under Usage Parameter Control (Part 2) (Japan) Hardware experimental results are reported for the relationship between the encoder buffer delay and the Leaky Bucket Size, concluding that apart from the obvious relationship (e.g. encoder buffer delay is inversely proportional to the Peak Rate) Leaky Bucket Size does not have critical effect on encoder buffer delay for the applied coding parameter control method (VBR mode if Leaky Bucket occupancy < 90 % of Leaky Bucket Size, otherwise CBR operation). AVC-463 Consideration of MPEG-1 Systems as multimedia multiplexing for audiovisual communications (Japan) A case study of applying MPEG-1 Systems to the multimedia multiplex for high quality videoconferencing indicates that it is a possible method. Several items are discussed; constraint on number of packets per second which determines packetizing delay, correspondence between medium and stream_id which influences cross application bitstream interchange, implementation, impact of cell losses and rate control. It is concluded that necessary changes to the MPEG-2 program mux be urgently discussed and decided. AVC-464 Relation between MPEG-2 transport mux and ATM/AAL (Japan) An MPEG-2 transport mux being currently considered is compared with ATM/AAL Type 4 in functionality, indicating similarity to a great extend and encouraging further study. AVC-465 Video source clock recovery using network clock (Japan) Use of high quality network clock, if commonly available to the encoder and decoder, is discussed for video clock recovery. As a conclusion, addition of a one bit flag is proposed to indicate which of the internal or external sources is used by the encoder. AVC-466 Preliminary DSM control command requirements (PTT Research - NL) By listing a number of control commands related to the network database access, discussion is encouraged on an appropriate positioning of the MPEG specific controls in the complete control command picture. AVC-467 Interworking and complexity requirements on scalable video coding algorithms (PTT Research - NL) Pel-split and DCT-split schemes to achieve scalable video coding are compared in terms of interworking, complexity, flexibility and visual quality, leading to the former as a conclusion. AVC-468 System multiplexing and priorities (PTT Research - NL) Relationship between the MPEG-2 transport mux and B-ISDN functionalities is discussed with a focus on the transmitting priority. AVC-469 Stereoscopic video transmission: a future application of spatial embedded coding (PTT Research - NL) Stereoscopic video transmission is given as an effective application of the spatial scalable embedded coding, where disparity compensated prediction is used to improve coding efficiency of the second channel. AVC-470 MPEG-2 syntax (F, UK, B, I, N, D, NL, CH) A proposal is made to maintain hooks in the MPEG-2 syntax for spatial scalability/compatibility for providing HD/ED/SD/LFDV and communication applications. AVC-471 Variable slice sizes vs small fixed slice sizes (Australia) This contribution considers the effect of trying to match the length of a slice to a multiple of the cell payload length by varying the number of macroblocks within a slice and to start a slice as soon as possible after the start of a cell. A number of different multiples of the cell payload length are investigated to determine the change in overall sequence quality and average number of cells in a slice. Error resilience of this approach is compared with that of a fixed number of macroblocks per slice, resulting in no significant difference. AVC-472 Cell loss resilience of data partitioning (Australia) Experimental results are presented for two layer data partitioning by the PBP method. First, portions of the bits in the lower layer are given for different values of PBP. Then, error resilience experiments are reported comparing non-partitioned and partitioned streams, summarizing that the data partitioning offered improved quality under cell loss even when only one priority level is used and that the quality improvement was more noticeable under high cell loss conditions. AVC-473 Report of Ad-hoc Group on ATM Cell Loss Error Resilience (Australia) This document is a report of the adhoc group activities established at the Rome meeting, which contains a proposed informative text for error resilience techniques in WD covering error concealment (decoder only and encoder assisted), spatial localization and temporal localization. AVC-474 Bitsavings on the prediction_weight_code (BT, PTT Research) Based on the coding efficiency gain for the prediction_weight_code of 1.04 % in the top layer of 1.15+2.85 Mbit/s environment, differential coding like quantizer_scale is proposed. AVC-475 MPEG Systems and B-ISDN (Australia) After comparing layered protocol models between B-ISDN and MPEG systems under consideration, AAL Type 2 possibilities and relevant MPEG-2 systems functions are discussed. As a conclusion, it is proposed that a layered MPEG-2 systems protocol model be defined which will allow the service in a lower layer to be provided by further MPEG-2 systems layers, or an appropriate B-ISDN layer. AVC-476 Data Partitioning and the Main Profile (Australia) Desirability is sated that the main profile decode be able to handle two partitions because this will provide improved performance at a small increase in decoder complexity. AVC-477 Layered coding informative text (Australia) Description for layered coding is given to provide for information on three strategies; data partitioning, frequency scalable pyramid, spatial scalable pyramid. As an illustration of error resilient coding, a two layer data partitioning scheme and the use of two channels with different error performance are detailed. AVC-478 Effectiveness of Data Extraction for Interlaced Source Material (Australia) Experimental results are reported for two modes of 4x4 data extraction from coded Bus sequence; field mode with simple extraction and frame mode with 4x3+4x1 extraction. It is concluded that the former method leads to a better quality extracted image. AVC-479 Evaluation of Scalable Coding Schemes (Australia) Two scalable coding approaches, frequency scalable and spatial scalable, are compared with simulcast concerning interworking capabilities, coding performance, network issues, compatibility with existing standards hardware complexity, functionality and applications. It is concluded that though both methods can provide layered coding with resolution scalability, they do not serve as alternatives; emphasis on flexibility and compatibility leads to spatial scalable scheme, emphasis on efficiency and simplicity leads to frequency scalable scheme. AVC-480 Quantization of spatially scalable prediction errors (BT) Experimental results are reported for comparison between four quantization methods for 1.5 + 2.5 Mbit/s compatible coding; 1) normal quantization for all transform coefficients and the inter weighting matrix, 2) normal but with a step size of 8, 3) normal but with intra weighting matrix, 4) DC-8 + intra weighting matrix. As a conclusion, it is proposed that the first quantization method for spatially scalable macroblocks be standardized. AVC-481 The use of MPEG-2/H.26X for low bit rate applications (BT) This document first argues that MPEG-2/H.26X should support low bit rate operations as it is a generic standard. Then, limitations of the current syntax and some proposed changes are provided; 1) skipping any macroblock be allowed, and all macroblock coding parameters have default values, 2) picture skipping with no data at all be allowed, 3) indication of required maximum decodable rate be included in the sequence layer. AVC-482 Enhancement of spatial scalability for reduced cost decoders (BT) This document describes the current spatial scalable scheme and a variation of it that allows reduced cost decoders and show that the two schemes can be merged into a hybrid scheme to allow the use of reduced cost decoders. The two schemes are compared in terms of implementation aspects and error resilience. AVC-483 Sequence Layer Syntax (BT) This document describes some of the limitations of the current sequence level syntax and proposes changes to overcome these limitations; 1) to allow change of prediction weighting matrices when sequence data is repeated, 2) to allow user data to appear before extension data and for sequence header data to occur without the to have preceding group of pictures and intra data, 3) to make it a syntax element, 4) to give the same status to sequence_data, pictures, extension_data, and user_data. 5) to attach syntax diagrams to the standard, 6)to include profile and level ID instead of constrained parameter flag. AVC-484 List of open issues, Version 2 (Chairman) This is an updated version of AVC_436. Open issues are listed with description of options, status, input required. aimed Recommendation, applications and target date according to the following categories; - framework for video coding standardization, - picture format, - video coding, - VBR vs CBR, - interface with networks, - end-to-end signalling, - multipoint communication system, - B-N interworking, - audio coding. Background information such as system configuration, applications, milestones and target date (priority) is also contained. AVC-485 Experimental results with AC leaky prediction (AT&T) Experimental results are reported concerning quality without cell losses or channel changing, speed of channel changing and quality with cell losses. Fast forward and fast reverse modes using AC leak is also discussed. AVC-486 Harmonising/combining low complexity, error resilience, scalability, image quality and compatibility (PTT Research) Configurations of decoder and encoder are discussed which allow integration of low complexity, error resilient, SNR scalability, resolution scalability and compatibility without changing the current macroblock layer syntax. AVC-487 CCITT patent policy and MPEG-2 patent status (Siemens AG) It is pointed out that technical proposals should include patent information according to the CCITT patent policy. AVC-488 Results on TM4 prediction Core Experiment on mod. SVMC-Prime (Tektronix) Experimental results are reported on SNR among prediction modes; Frame/Field, Frame/Field,/Dual-prime, and Frame/Field/Dual-prime/SVMC-prime. As a conclusion, it is recommended that SVMC-prime be dropped from further considerations. AVC-489 Some results on Frequency scalability Experiments I.4 (Tektronix) Experimental results are reported on multichannel scalability using Scalable Side Information syntax extensions; three layers (1/4, 1, 1) and two layers (1/4,1), (1/16,1) with lower scale layer reference signal derived from field DCT subsampling. It is concluded that the SSI syntax should support field or field/frame adaptive processing since frame based coding shows less coding efficiency for fast motion sequences, and that Extended MQUANT may be required for difficult to code sequences at constrained low bit rates. AVC-490 H.26X error resiliency based on data partitioning and concealment (Tektronix) Experimental results are reported for the two layer partition of PBP_1(0) and PBP_1(2) with motion interpolation concealment under cell loss ratio of 10**(-3). It is concluded that a combination of data partitioning and concealment techniques provide a powerful and yet simple tool for cell loss protection. AVC-491b Test Model 5 (Test Model Editing Committee) This is a revision reflecting the achievements obtained at the Sydney meeting. AVC-492 Revised syntax and semantics for MPEG-2 video (Video syntax sub-group) This is a delta document to the Working Draft (AVC-449) containing specifications for Main Profile at Main Level which has been frozen at the Sydney meeting. AVC-493 MPEG-2 Systems Working Draft (Systems Committee) This is a revised document of WD which reflects the achievements at the Sydney meeting. AVC-494 Simulation results on CTV/HDTV compatible coding (ETRI) Experimental results are reported for comparison between pyramidal coding and spatio-temporal compatible coding. Both are coding HDTV (1920x1024 luminance pels, 4:2:2) and embedded CTV (960x512 luminance pels, 4:2:2). It is concluded that both performance of compatible coding methods is quite similar and that both schemes give quite compatible picture quality. AVC-495 Multi-channel information carried by Systems layer (Australian UVC, IBM, Tektronix) It is discussed that certain basic information describing the multi-layer video need be carried in the Systems layer; at t he very minimum a service mapping table which relates packets and multi-layer entry types such as FSn (frequency scalable layer n), SSn (spatial scalable layer n) and DPn (data partitioning layer n). END Annex 1 to AVC-553R Documents for the Boston/New York meeting (7-16 July 1993) Normal Documents AVC number MPEG93/... Pur- pose Title (source) AVC-491b N400 R Test Model 5 (Test Model Editing Committee) AVC-496R R Report of the eleventh meeting in Sydney and Melbourne - March 27 - April 7, 1993 (Chairman) AVC-497 ??? R MPEG-2 Working Draft - Video Part - Version 4 (Working Draft Editing Committee) AVC-498 - D Work plan for broadband audiovisual systems Recommendations (S. Okubo) AVC-499 - R Report of ITU-TS SG 15 Rapporteru's meeting in Tokyo (N D Kenyon) AVC-500 - P Multipoint 4 QCIF to CIF video mixing (Bellcore) AVC-501 - I Simulation studies of 4 QCIF to CIF video mixing (Bellcore) AVC-502 R MPEG 2 Ssytems Working Draft (Systems Committee Adhoc Group) AVC-503 493 I Performance of the Mian Profile @ Main Level - distributive and interactive services (BELGACOM, UCL) AVC-504 494 I MPEG-2|H.26X error resilience based on data partitioning (BELGACOM, UCL) AVC-505 495 I New results on spatial scalability ((BELGACOM, UCL) AVC-506 P Concern regarding MPEG-2 Systems and ATM/AAL functionality (Australia) AVC-507 567 D H.32X terminal and MPEG-2 Systems (Aus. UVC) AVC-508 568 D B-ISDN & Video Services Tutorial (S. Dunstan, Siemens) AVC-509 516 P Flexible Object Oriented Decoding Using Slice Identification (Aus. UVC) AVC-510 517 I FF & FR using Frequency Scalability layered coding (Aus. UVC) AVC-511 528 I/P Report of Ad-hoc Group on ATM Cell Loss and Error Resilience (M. Biggar, chair) AVC-512 - P Design of H.32z terminals for LANs (Aus. UVC) AVC-513 - P H.22z protocol for LANs (Aus. UVC) AVC-514 546 P Time stamp for a large picture (Japan) AVC-515 547 P Considerations on AC-leaky Prediction (Japan) AVC-516 548 D Considerations on the next profile (Japan) AVC-517 549 D Practical examples of Hierarchical coding (Japan) AVC-518 550 P Syntax modification for compatibility/spatial scalability (Japan) AVC-519 551 P VBV operarion in 3:2 pulldown (Japan) AVC-520 552 D Some considerations on the coding segments (Japan) AVC-521 599 P Correction method for cell loss and bit error in AAL Type 1 (Japan) AVC-522 - I VBR coding and octet interleave (Japan) AVC-523 - I Low delay IPB mode transmisssion using VBR (Japan) AVC-524 553 D Relation between MPEG-2 transport mux and ATM/ALL and possible candidates for AAL (Japan) AVC-525 514 P Telecommunication requirements for the Next profile (NL,I,UK,N,FRG) AVC-526 D Telecommunication levels for the Next profile (NL,I,UK,N,FRG) AVC-527 545 I Software decoding of video streams (PTT Research) AVC-528 543 I Inter working between wide screen SCIF and SCIF video conferencing systems (PTT Research) AVC-529 561 I On the B-frame design complexity of spatio-temporal weighting (PTT Research) AVC-530 P European stance on leaky prediction (F,FRG,B,N,I,NL,UK) AVC-531 639 I Simulation results on AC-leaky prediction (France) AVC-532 638 I Cell loss resilience : simulation results on concealment techniques (France) AVC-533 636 I Experiment on spatial/temporal H.261/H.26x compatibility (France) AVC-534 569 I Comparison of CTV/HDTV compatible coding schemes (ETRI) AVC-535 - I Invitation to the 14th ATM Video Coding Meeting (ETRI) AVC-536 620 P Cleanup of AC-Leak Syntax and Specification (AT&T) AVC-537 686 I Comparison of the Cell-Loss Resilience of MPEG-2 Main Profile and AC-leaky prediction (AT&T) AVC-538 - P Method for the correction of cell losses for low bit-rate signals transport with the AAL Type 1 (France) AVC-539 631 P Semantics for skipped macroblocks in spatial scalability (BT) AVC-540 632 P Semantics for prediction of motion vector in spatial scalability (BT) AVC-541 633 P Syntax and semantic extensions for spatial scalability (BT) AVC-542 634 I/P Spatio-temporal weighting experiments (BT) AVC-543 635 I/P Accuracy requirements of upsampling (BT) AVC-544 641 I/P Frequency adapted spatio-temporal weighting (BT) AVC-545 I Results on spatial scalability Core Expt. TM5 G.6.6 (Tektronix) AVC-546 614 D Missing information and inconsistencies in TM2, MPEG2 Working Draft (Tektronix) AVC-547 645 D/P Preliminary studies into ATM mapping of MPEG-2 Transport Layer Packets (BT) AVC-548 678 I/P Experiments on the effect of losses of picture-type or f-code in picture headers (David Sarnoff) AVC-549 679 I/P Experiments on the effect of loss of quantizer matrices in picture headers (David Sarnoff) AVC-550 637 D/P About the transfer of MPEG transport packets in ATM (CNET) AVC-551 - P ITU-TS patent policy and MPEG-2 follow up (Siemens) AVC-552 N0491 R Test Model 6 (Test Model Editing Committee) Abstracts AVC-491 Test Model 5 (Test Model Editing Committee) This is a revision reflecting the achievements obtained at the Sydney meeting. AVC-496R Report of the eleventh meeting in Sydney and Melbourne - March 27 - April 7, 1993 (Chairman) This document records the outcome of the sole and joint sessions held in March-April 1993. AVC-497 MPEG-2 Working Draft - Video Part - Version 4 (Working Draft Editing Committee) This document provides agreed syntax and other texts for the video part which were edited after the Sydney meeting. AVC-498 Work plan for broadband audiovisual systems Recommendations (S. Okubo) This document is reproduction of a contribution to SG15 Rapporteur's meeting held in May 1993 which raised the following for discussion; Time schedule for system aspects Recommendations, Consideration of MPEG-2 multimedia multiplex schemes for broadband applications, Protocols for desktop videoconferencing. AVC-499 Report of ITU-TS SG 15 Rapporteur's meeting in Tokyo (N D Kenyon) This is a report of the three day SG15 Rapporteur's meeting held in May 1993, covering H.KEY, AV.420, JPEG profile and protocols for AV Recommendations, channel aggregation, data transmission in H.320-based systems, and workplan for broadband audiovisual communications. AVC-500 Multipoint 4 QCIF to CIF video mixing (Bellcore) System control aspects are discussed for achieving continuous presence multipoint videoconferencing using 4 QCIF to CIF video mixing. This document is reproduction of a contribution to SG15 Rapporteur's meeting held in May 1993. AVC-501 Simulation studies of 4 QCIF to CIF video mixing (Bellcore) Video coding aspects of 4 QCIF to CIF video mixing are discussed evaluating end-to-end delay, picture quality, buffer sizes and system complexity. Experimental results are also reported, indicating that intra slice method is effective in reducing delay. This document is reproduction of a contribution to SG15 Rapporteur's meeting held in May 1993. AVC-502 MPEG 2 Ssytems Working Draft (Systems Committee Adhoc Group) This was generated a the Amdsterdam meeting of the Systems Adhoc Group in June 1993. AVC-503 Performance of the Main Profile @ Main Level - distributive and interactive services (BELGACOM, UCL) Coded results for a fixed step size are presented with bit generation statistics and processed pictures. Original PAL sources of videoconferencing like sequence and TV programs are encoded with (M=1, N=50) and (M=3, N=50???), respectively. AVC-504 MPEG-2 / H.26X error resilience based on data partitioning (BELGACOM, UCL) Coded results for 2-layer data partitioning are presented where the bitstream generated is packetized at the slice level into two priorities with the low priority layer suffering 10-3 CLR. Coded pictures for two sequences and two different sets of PBP values are demonstrated. AVC-505 New results on spatial scalability (BELGACOM, UCL) Experimental results are reported on comparison of simulcast vs spatial scalable coding for TV and HDTV. SNR data and processed pictures are presented for total of 20 and 25 Mbit/s where 6 Mbit/s is assigned to the TV coding. Spatial scalable shows 0.5 dB SNR increase compared to simulcast. AVC-506 Concern regarding MPEG-2 Systems and ATM/AAL functionality (Australia) Concern is expressed that ITU-TS SG15's indication of desire to use MPEG-2 Systems specifications for audiovisual communications is premature. It is concluded that the definition of AAL Type 2 is a matter of urgency which this Experts Group should undertake at the earliest possible time, and that the objectives should include recommendations to SG13 for functionality for a generic AAL Type 2 that allows full exploitation of the network functionality while still working with MPEG-2 Systems in a simple, efficient manner. AVC-507 H.32X terminal and MPEG-2 Systems (Aus. UVC) This document presents an overview of H.32X terminal, AAL functionality for an audiovisual terminal, illustration of data flow in the H.32X terminal, MPEG-2 Systems functionality, and some scenarios for coping with the overlap between MPEG-2 Systems and AAL/ATM. AAL Type 2 proposal is attached which consists of SAR (ST/SN/HEC/47 Bytes SAR-PDU payload) and CS (CMI/TS/variable size CS-PDU payload/PAD/LI/CRC). As a conclusion, importance is stressed for establishing required AAL modes of operation before suitable mechanisms to support them are determined. AVC-508 B-ISDN & Video Services Tutorial (S. Dunstan, Siemens) This document gives an overview of B-ISDN as described in the ITU-TS Recommendations, covering B-ISDN services, Protocol Reference Model, ATM layer, switching and network functions, AAL layer and signalling. The aim is to assist in a common understanding of B-ISDN principles and terminology. AVC-509 Flexible Object Oriented Decoding Using Slice Identification (Aus. UVC) An idea is presented to allow separately encoding objects which consist of slices with identical identification, thus to allow separate and complete decoding of each object individually. Each object may have fixed/variable shape and fixed/variable position from one frame to another. For this purpose, a new syntax element slice_id (4 bits) is proposed for inclusion in the slice header. AVC-510 FF & FR using Frequency Scalability layered coding (Aus. UVC) Experimental results are reported for use of Frequency Scalability to achieve FF/FR functionality. Speed up factor of 3 and 12 have been simulated for a 3-layer scheme with the lowest layer containing at maximum 2x2 DCT coefficients. AVC-511 Report of Ad-hoc Group on ATM Cell Loss and Error Resilience (M. Biggar, chair) This is a report of the adhoc group activities after the Sydney meeting in March - April 1993. Some discussions are described and error resilience description is offered for inclusion in the Working Draft. AVC-512 Design of H.32z terminals for LANs (Aus. UVC) Two options for the design of LAN-attached desktop multimedia terminals (H.32z terrminals) are discussed; one is to retain H.221 framing and to place one or more H.221 frames into packets for transmission across the LAN, the other is to packetize each data stream (video, audio, signalling, etc.) and to transmit them separately across the LAN using a different LAN packet. AVC-513 H.22z protocol for LANs (Aus. UVC) This document describes an H.22z protocol for transporting real-time audiovisual/multimedia information over packet switched local area computer networks. The required functions are identified; packetization, multiplexing, error handling and timing recovery. Then a corresponding packet structure is proposed. AVC-514 Time stamp for a large picture (Japan) A proposal is made to the definition of Presentation Time Stamp for "large pictures", which is followed by skipped pictures, and to the handling of such PTS at the decoder. The solution is similar in approach to the one for VBV; if the buffer does not contain complete data at the time indicated by PTS, no action is taken and checking the buffer proceeds to the next timing. AVC-515 Considerations on AC-leaky Prediction (Japan) After having reviewed previously obtained study results, preference is given to that AC-leaky prediction should be outside Next Profile since existing Intra Slice and Short Slice methods provide similar effects. AVC-516 Considerations on the next profile (Japan) This document lists syntactic elements which may be included in the Next Profile and provides four possible solutions, out of which Solution C (to define a single Next Profile with selected mandatory elements) is concluded preferable. Then requirements from the audiovisual communication applications are discussed to conclude that Spatial Scalable Extension should be included as a minimum for H.261 backward compatibility and error resilience. AVC-517 Practical examples of Hierarchical coding (Japan) This document lists practical examples of hierarchical coding, indicating picture and syntax of each hierarchy. Some questions are raised toward definition of the Next Profile. AVC-518 Syntax modification for compatibility/spatial scalability (Japan) A modified syntax is proposed to remove redundancy in motion vectors for spatial only prediction and in prediction_weight_code for full spatial prediction macroblocks. Experimental results are presented to verify the effectiveness of this modification. AVC-519 VBV operarion in 3:2 pulldown (Japan) Based on a review of the 3:2 pulldown related coding operation, the following is proposed; Period t of the VBV operation should be calculated on the parameters contained in the last picture removed from the buffer. Coding should be carefully controlled for 3:2 pulldown so that VBV specification is not violated due to the change of field_count sequence between the source order and the coding order. Picture skipping must not take place in the 3:2 pulldown mode. AVC-520 Some considerations on the coding segments(Japan) Coding-decoding delay is analyzed for concatenation of M=3 and M=1 segments. It is pointed out that some care should be paid in coding control to maintain low buffering delay and to avoid VBV violation. AVC-521 Correction method for cell loss and bit error in AAL Type 1 (Japan) A cell interleaving method for AAL Type 1 is proposed which applies RS(48,44) to a block of 12 cells. This FEC code has capability of correcting a single cell loss in the block with encoding-decoding delay of 24 ms at 384 kbit/s. This document also discusses separation between SAR and CS, protection against successive cell losses, hardware complexity and extension to other AAL. Items requiring SG13 advice are pointed out; partitioning SAR and CS, use of CSI bits. AVC-522 VBR coding and octet interleave (Japan) Experimental results are reported for the two methods to give upperbound for the octet interleaving delay; to keep a minimum bitrate, and to set a time-out for flushing the interleaver matrix. It is shown that both methods are effective in reducing the delay and increase of the step size is small, particularly if there is more strict UPC. AVC-523 Low delay IPB mode transmisssion using VBR (Japan) Experimental results are reported to achieve low delay by the utilizaion of periodical nature of the VBR coded bit generation in IPB structures. Two mehtods are studied; use of special relationship bwteen the GOP size and UPC window size, and declaration of a higher average bitrate. AVC-524 Relation between MPEG-2 transport mux and ATM/ALL and possible candidates for AAL (Japan) Based on review of the MPEG-2 Systems and the I.363 AAL, relationship between them is discussed for designing audiovisual communication terminals. It is concluded that use of PES packets may be preferable for video service integration, but use of TS packets may be redundant. A notion of H.32X transport packet is offered for discussion which segments the PES packet and have such features as variable length to support different QoS, software implementation. Appropriate AALs to transfer the H.32X transport packets are also discussed; Type 5 and Type 4 SAR modified. AVC-525 Telecommunication requirements for the Next profile (NL,I,UK,N,FRG) The following requirements from telecommunication applications are listed as mandatory; H.320 interworking (including video, audio, multiplexing, call control, etc.), H.261 compatibility, MPEG-1 compatibility (including video, audio, systems), low end-to-end delay (less than 150ms), cell loss resiliency (up to 10-2 CLR), bitrate range from 64 kbit/s to several tens of Mbit/s. AVC-526 Telecommunication levels for the Next profile (NL,I,UK,N,FRG) Two specific levels in the Next Profile is discussed for telecommunication applications; Main level, (wide screen) SCIF level. Selection of syntactic elements for the Next Profile is also discussed by marking the TM5 syntax. AVC-527 Software decoding of video streams (PTT Research) Information is provided on the design and implementation of a software decoder for MPEG-1 video streams (paper by K. Patel et al). It is shown that memory bandwidth is the primary limitation in performance of the decoder, not the computational complexity of IDCT. AVC-528 Inter working between wide screen SCIF and SCIF video conferencing systems (PTT Research) The following three interworking situations are depicted which are covered by the MPEG-2 syntax; interworking between the H.32X B-ISDN normal screen terminal operating at SCIF and the H.320 N-ISDN terminal operating at CIF, interworking between the 16:9 wide screen SCIF terminal and the 4:3 normal screen SCIF terminal by means of side panel, interworking among the three stated above. AVC-529 On the B-frame design complexity of spatio-temporal weighting (NL) This document examines hardware complexity for supporting B frames and spatio-temporal weighting, obtaining the following conclusion; Spatio-temporal weighting gives a gain in SNR performance which may further increase by the future techniques. It requires higher memory bandwidth, but if B frames are incorporated, the resource can also be used for spatio-temporal weighting in I and P pictures. For M=1 coding, support of spatio-temporal weighting requires additional memory bandwidth. AVC-530 European stance on leaky prediction (F,FRG,B,N,I,NL,UK) The inclusion of the AC-leaky prediction is not supported, for error concealment purpose, in the NEXT or the SIMPLE profile on the grounds that it does not outperform other existing solutions. AVC-531 Simulation results on AC-leaky prediction (F) This paper follows the main guidelines of Core Experiment F4 on AC-leaky prediction. The following aspects are tested : coding performances without loss and cell loss concealment capability. AVC-532 Cell loss resilience: simulation results on concealment techniques (F) This paper provides some results on the concealment techniques proposed in TM5 : Substitution from previous frame with and without motion compensation , Intra MV. Simulations are done in M=1 context. AVC-533 Experiment on spatial/temporal H.261/H.26x compatibility (F) This paper presents the results of a (core) experiment about H.261/H.26x compatibility by using the two layered prediction scheme. We used the prediction_weight_code table proposed in TM5 , which includes a half compatible/half temporal prediction. Simulation results and our point of view concerning the need of this latter prediction mode are given. AVC-534 Comparison of CTV/HDTV compatible coding schemes (ETRI) Coding performance (SNR) is reported for the following two CTV/HDTV compatible coding schemes at 12+13.5 Mbit/s; pyramidal DCT, and spatio-temporal predictive coding. Both of the base layer and upper layer use TM5. Two up/down conversion filters of CMTT and MPEG are also compared. It is concluded that the spatio-temporal prediction method gives a little superior performance and that the TM5 filters give better performance in the spatio-temporal scheme. AVC-535 Invitation to the 14th ATM Video Coding Meeting (ETRI) This document provides information on the meeting in Daejon AVC-536 Cleanup of AC-Leak Syntax and Specification (AT&T) AC-leak syntax is proposed to be a separate extension with its own unique identifier. Semantics for the AC-leak are also clarified. AVC-537 Comparison of the Cell-Loss Resilience of MPEG-2 Main Profile and AC-leaky prediction (AT&T) Experimental results are reported for the AC-leak method comparing with the Main Profile (N=15); quality when there is no error, cell loss resilience, and channel hopping speed. It is concluded that; quality for M=1 with D=6 and N=15 is nearly identical, the AC-leak gives visually less objectionable pictures against cell losses, particularly with D=6, in the worst case a very clear image is available after 12 frames with D=6, but the picture is very recognizable after 6 frames. AVC-538 Method for the correction of cell losses for low bit-rate signals transport with the AAL Type 1 (France) This documents intends to respond to the liaison from TG CMTT/3 which is requiring a cell loss correction method adapted to high quality sound transmission with low delay at low bitrates. The method uses diagonal octet interleaving for 16 cells and FEC (RS codes). As a conclusion, a common cell loss correction method is proposed for all real-time low bit-rate services using AAL type 1. AVC-539 Semantics for skipped macroblocks in spatial scalability (BT) This document proposes clarification and addition to WD for skipped macroblocks taking spatial scalability into account. AVC-540 Semantics for prediction of motion vector in spatial scalability (BT) This document proposes clarification and addition to WD for prediction of motion vector to include spatial scalability. VLCs for macroblock_type are also proposed. AVC-541 Syntax and semantic extensions for spatial scalability (BT) This document proposes a picture layer syntax for spatial scalability as well as a macroblock layer syntax for snr scalability. AVC-542 Spatio-temporal weighting experiments (BT) Experimental results are reported for coding efficiency and picture quality of the three methods of spatio-temporal prediction; simple switching, simple switching plus averaging, optimum continuous weights. It is concluded that the third method which requires downloadable weights is not worth the cost, and that the second average mode method gives a little gain, while increasing the complexity a little, thus is proposed to be in the standard. AVC-543 Accuracy requirements of upsampling (BT) Experimental results are reported for comparison between 4 different upsampling filters in the decoder in the spatial scalable scheme where an encoder upsampling filter is used It is concluded that the upsampling process need not be performed exactly the same in the encoder and decoder to get the same subjective picture quality at the encoder and decoder and that the simplest interpolation is sufficient. The pel repetition, however, gives poor quality. AVC-544 Frequency adapted spatio-temporal weighting (BT) Experimental results are reported for frequency adapted spatio-temporal prediction where the spatio-temporal prediction signal is derived by averaging the two horizontally low passed components (spatial one and temporal one) and adding the temporal high pass component. It is concluded that this technique gives a small but noticeable gain, thus a core experiment is proposed for its optimization. AVC-545 Results on spatial scalability Core Expt. TM5 G.6.6 (Tektronix) Experimental results are reported for comparison of coding efficiency (SNR) between simulcast, spatial scalability with weighted prediction and spatial scalability with binary selection. It is concluded that there is an SNR gain from using either of spatial scalability and that spatial scalability with binary selection performs better than spatial scalability with weighted prediction. It is also stated that spatio-temporal weighting adds hardware complexity. AVC-546 Missing information and inconsistencies in TM5, MPEG2 Working Draft (Tektronix) Some items needing correction or new definition are pointed out for the specifications of WD (MP@ML) and TM5 (spatial scalability). AVC-547 Preliminary studies into ATM mapping of MPEG-2 Transport Layer Packets (BT) AVC-550 About the transfer of MPEG transport packets in ATM (CNET) Methods for transmitting MPEG-2 TS packets over ATM networks are discussed referring to the Bellcore contribution to the Atlanta Systems group meeting. Assuming that transmission efficiency and cell loss resilience are of prime importance, the following scenario is proposed as the best compromise; use of AAL Type 1, no padding octets by use if "alignment" mapping and packet length of nx47 octets. AVC-548 Experiments on the effect of losses of picture-type or f-code in picture headers (David Sarnoff) Experimental results are reported on the impacts of picture header information loss causing serious damage in decoded pictures. It is proposed to allow redundant transmission of very sensitive data within the picture headers to improve the noise channel performance. AVC-549 Experiments on the effect of loss of quantizer matrices in picture headers (David Sarnoff) Experimental results are reported on the impacts of quantizer matrix information loss. It is concluded that quantizer matrix changes slightly degrade the quality of decoded pictures, thus redundant transmission of this information is not required. AVC-551 ITU-TS patent policy and MPEG-2 follow up (Siemens) The ITU-TS policy is reminded and it is proposed that the AVC Rapporteur Group starts collecting patent information and that the Group declares its desire to follow the waiving approach. AVC-552 Test Model 6 (Test Model Editing Committee) This document describes experiments on optimization of upconversion filter for spatial scalability, optimization of macroblock type tables and verification of temporal scalability. Temporary Documents TD-1 Chairman Agenda for the sole sessions in Boston TD-2 Chairman Available documents for the Boston/New York meeting TD-3 Chairman List of tape demonstrations TD-4 G. Bjoentegaard Proposed text for WD Annex C TD-5 Chairman List of open issues - April 1993 TD-6 Chairman Fields in Protocol Data Unit and their functions TD-7 Chairman Independent clocks and their recovery methods TD-8 S. Dunstan Results of meeting to discuss ATM/AAL and MPEG-2 Systems TD-9 Chairman Summary of the discussion on AC-leaky prediction TD-10 S. Okubo, K. Asai Cell loss correction method for AAL Type 1 to support H.320 terminals in B-ISDN TD-11 Chairman Agreements and actions (substitute of the meeting report) TD-12 A. Tabatabai Report of the small group work to sort out the discrepancies in proposed solutions for the spatial scalable syntax END Annex 1 to AVC-578R Documents for the Brussles meeting (2-10 September 1993) Normal Documents AVC number MPEG93/??? Pur-pose Title (Source) AVC-552 N0491 R Test Model 6 (Test Model Editing Committee) AVC-553R 802 R Report of the twelfth meeting in Boston and New York (July 7-16, 1993) - Part I and Part II (Chairman) AVC-554R 802 R Report of the twelfth meeting in Boston and New York (July 7-16, 1993) - Part III (Chairman) AVC-555 N0502 R Third Working Draft - Video (WD Editing Committee) AVC-556 N0501 R Third Working Draft - Systems (WD Editing Committee) AVC-557 - R Liaison statements to SG15 Experts Group for ATM Video Coding (SG13) AVC-558 - R Report of drafting meeting on the Terms of Reference for JCG on B-ISDN (D. Dorman) AVC-559 - D Comments on Bellcore continuous presence multipoint proposal (BT) AVC-560 - I/D Some comments on video combining from 4 QCIFs to CIF (Bellcore) AVC-561 - P Proposal for work plan of ITU-T WP1/15 (BT) AVC-562 747 I Experiments on asynchronous video clock (Japan) AVC-563 748 P/D Modification to the current VBV specification (Japan) AVC-564 - D Backward compatibility with H.261 using NEXT Profile (Japan) AVC-565 746 D Problems in Data Partitioning (Japan) AVC-566 - P Proposal for field trial of H.32X ATM video codec (Japan) AVC-567 749 D Bit error consideration on H.22X/AAL (Japan) AVC-568 750 D MPEG2 Transport packet transmission over ATM (Japan) AVC-569 751 D Consideration on the diagonal interleaving method for cell loss correction (Japan) AVC-570 730 P PES packet length semantics (Siemens) AVC-571 - P H.261 backward compatibility (Telecom Australia) AVC-572 - P Proposal for a profile incorporating minimum complexity scalability (Telecom Australia) AVC-573 745 The effect of up-sampling on two-layered coding (BT?) AVC-574 787 I NEXT Profile Level Parameters for 4:2:0 formats (PTT Research) AVC-575 - Video Coding Aspects of the Bellcore 4 QCIF to CIF mixing proposal (PTT Research) AVC-576 - D/I Error resilience based on Data Partitioning (BELGACOM, UCL) AVC-577 - P Data partitioning addition to Working Draft (DSRC) Abstracts [???] indicates MPEG Document Number MPEG93/???. AVC-552 [N0491] Test Model 6 (Test Model Editing Committee) Three remaining experiments are described, optimization of the upconversion filter for spatial scalability, optimization of macroblock type tables for scalability, and verification of temporal scalability. AVC-553R [802] Report of the twelfth meeting in Boston and New York (July 7-16, 1993) - Part I and Part II (Chairman) This document records the outcome of the sole sessions held in Boston July 1993. AVC-554R [802] Report of the twelfth meeting in Boston and New York (July 7-16, 1993) - Part III (Chairman) This document records the outcome of the joint sessions with MPEG held in New York in July 1993. AVC-555 [N0502] Third Working Draft - Video (WD Editing Committee) This document gives frozen specifications for video coding part which were obtained at the New York meeting. AVC-556 [N0501] Third Working Draft - Systems (WD Editing Committee) This document gives frozen specifications for systems coding part which were obtained at the New York meeting. AVC-557 [-] Liaison statements to SG15 Experts Group for ATM Video Coding (SG13) This document contains the following liaison statements from SG13 which met during 5-16 July 1993 in Geneva; Open issues for AAL Type 1 timing recovery; impacts of Plesiochronous Network Operation, jitter absorbing capability of the Adaptive Clock method SG13's choice of the error correction method for delay sensitive signal transport of AAL Type 1 and an open issue - selection of the polynomial continuation of IVS Baseline Document activities AVC-558 [-] Report of drafting meeting on the Terms of Reference for JCG on B-ISDN (D. Dorman) Mandate, working methods, terms of reference, issues of immediate attention, etc., are described for a new joint coordination group "JCG on B-ISDN". Annex contains the release time table for B-ISDN standardization as a management tool for aligning B-ISDN related Recommendations. AVC-559 [-] Comments on Bellcore continuous presence multipoint proposal (BT) The method of achieving 2x2 split-screen continuous presence multipoint videoconferencing is commented with respect to use of fill bit, full screen display of pictures coded at 20 kbit/s, picture quality, delay, implementation cost of header manipulation etc. other than pure picture coding, impacts of picture dropping, video clock synchronization among remote terminals, use of existing terminals. It is concluded that the technique is not yet proven and may always suffer from disadvantages compared to the pel domain combining method. AVC-560 [-] Some comments on video combining from 4 QCIFs to CIF (Bellcore) The following is presented; There is a tradeoff between adding more MCU delay and violating the HRD sooner. Frame synchronization can be maintained by mapping input QCIF Temporal Reference on to regular output CIF Temporal Reference with a certain rule. Comparison between video combining and transcoding should carefully be studied in terms of picture quality, delay increase, cost and system complexity. AVC-561 [-] Proposal for work plan of ITU-T WP1/15 (BT) Taking into account of uncertainty in ATM network performance and timescales, a dearth of real and viable applications, and increasing number of customers asking for H.320 over LANs, this document proposes that H.320 over LANs become a prime focus for the work of SG15 to meet the shorter term needs. AVC-562 [747] Experiments on asynchronous video clock (Japan) Measurement and observation results are reported for asynchronous operation of a set of hardware HDTV coder and decoder where the decoder clock frequency is 10/20/30 ppm higher than the encoder one. A field slip appears as one-line downward or upward shift of the reproduced picture. Based on the fact that this one-line shift is seldom visible, it is concluded that asynchronous operation is of some practical use. AVC-563 [748] Modification to the current VBV specification (Japan) For 3:2 pulldown VBV operation, a missing specification is provided for the data removal timing at the start of sequence using vbv_delay values. A note for attention is also given for the coding of number_of_field_display_code at M > 1. AVC-564 [-] Backward compatibility with H.261 using NEXT Profile (Japan) Necessary provisions are discussed to implement H.261 backward compatibility by using the spatial scalability in Next Profile; parameter setting in the video syntax, layer indication in the H.22X multimedia multiplex, H.24X capability exchange for the combination of upper layer and lower layer. Some video issues are also listed; VBV, 5 bit TR in H.261, upsampling filter description and indication of progressive/interlace and chroma format for the lower layer. It is concluded that at least he following should be clarifies; handling of picture skipping in the lower layer, VBV specifications for the upper layer, identification of the layer by Systems. AVC-565 [746] Problems in Data Partitioning (Japan) Three alternatives for Data Partitioning syntax are compared; 1) DP elements in Sequence, Picture and Slice headers, 2) Extension syntax, 3) Informative description. Necessity of fine rate control in each layer leads to the first alternative. This document also points out possible start code emulation for which inhibition of the layer consisting of priority class 4 is concluded as the most reasonable. Issues of VBV_delay and bit_rate are also raised. AVC-566 [-] Proposal for field trial of H.32X ATM video codec (Japan) A field trial of H.32X terminal interconnection through ATM transmission lines is proposed to verify related draft Recommendations and to encourage early development of such products. Middle of 1995 is suggested for performing the field trial. Specifications looking at the early realistic applications and test methods needing special tools for ATM transmission are also discussed. AVC-567 [749] Bit error consideration on H.22X/AAL (Japan) Impacts of bit error are raised to reconsider H.22X/AAL for audiovisual services. Three strategies are discussed; 1) bit error detection and cell loss detection, 2) bit error correction and cell loss detection, 3) bit error correction and cell loss correction. A suggestion is given that the second strategy is preferable to the first one in some situations, though the Boston discussion was based on the first strategy. AVC-568 [750] MPEG2 Transport packet transmission over ATM (Japan) The following four methods are compared for transmission of TS packets over an ATM link; Byte/bit data transfer (bit pipe approach, AAL Type 1) structured data transfer (bit pipe approach, AAL Type 1) FEC and interleaving (bit pipe approach, AAL Type 1) alignment between a TS packet and ATM cells (packet approach, AAL Type 0 or new Type) It is concluded that the third method would be a good solution if cell loss correction is necessary but the fourth method if bit error correction is sufficient. AVC-569 [751] Consideration on the diagonal interleaving method for cell loss correction (Japan) This document discusses the use of Reed-Solomon code and interleaving for cell loss and/or bit error correction and proposes the following for AAL options; RS(94,88) and diagonal interleaving with ring buffer (SG13 proposal) for the lowest delay - bit by bit delivery, the same as above but with double buffer for application to the "stop-go" VBR operation - 752 Byte packet delivery, RS(192,188) and vertical interleaving for TS packets - 192x47 Byte packet delivery. AVC-570 [730] PES packet length semantics (Siemens) In order to achieve low delay, zero value of PES_packet_lentgh is proposed to be unspecified even if it is used without support from either the Program Stream or Transport Stream. It is also proposed that this should be true for any elementary streams. AVC-571 [-] H.261 backward compatibility (Telecom Australia) Due to the spatial scalable solution constraining the upper layer coding and other reasons, it is proposed that the ATM Video Coding Experts Group adopt a switchable/simulcast strategy to provide interworking between H.32X and H.320 terminals in those situation or at those times when this is required. AVC-572 [-] Proposal for a profile incorporating minimum complexity scalability (Telecom Australia) Considering that full support of Next Profile functionalities may be costly, this document proposes definition of a minimum scalability profile, incorporating those features currently in Main Profile, but also allowing 2-layer SNR scalability. AVC-573 [745] The effect of up-sampling on two-layered coding (BT) Experimental results are reported for comparison between the TM up-sampling filtering and linear interpolation. It is concluded that the up-sampling filtering process for the lower layer coded picture in a two-layer coder can be simplified to linear interpolation without any significant effect on the upper layer picture quality. AVC-574 [787] NEXT Profile Level Parameters for 4:2:0 formats (PTT Research) Taking into account that the processing power and memory size do not differ between luminance and chrominance pels, this document suggests that the level parameter should address total pixel rate (= luminance pixel rate + chrominance pel rate). It is also suggested that the level parameters for Next Profile should make distinction between 4:2:2 and 4:2:0 since progressive pictures are effective for high quality videoconferencing. AVC-575 [-] Video Coding Aspects of the Bellcore 4 QCIF to CIF mixing proposal (PTT Research) This document summarizes various comments to the Bellcore 4 QCIF to CIF video mixing proposal in AVC-500 and 501 which were obtained through correspondence. The comments cover questions to be answered, service aspects, approaches to the continuous presence multipoint system, impact on equipment, buffering and delay, picture quality, etc. It is concluded that the proposed method is simple in its basics and does not degrade picture quality, but there are some drawbacks. AVC-576 [-] Error resilience based on Data Partitioning (BELGACOM, UCL) Experimental results for cell loss resilience are reported for two different sets of PBP in terms of information splitting ratio and picture quality. It is raised whether we want the PBP information included in the H.26X bitstream at the slice level to allow constant bit rate mode in each of the two layers. AVC-577 [-] Data partitioning addition to Working Draft (DSRC) This document proposes syntax and other descriptions for the use of Data Partitioning. Temporary Documents TD-1 Chairman Agenda for the sole sessions TD-2 Chairman Available documents for the Brussels meeting TD-3 Chairman List of tape demonstrations TD-4 Chairman List of open issues - August 1993 TD-5 Chairman Fifth progress report of the Experts Group (Draft) TD-6 S. Okubo ITU-T approval process for Recommendation H.26X|MPEG-2 Standard (MPEG93/752) TD-7 Chairman Skeleton of Recommendation H.32X TD-8 K. Sakai Supplements to AVC-563 TD-9 Chairman Agreements TD-10 Chairman Video coding aspects of the Bellcore 4 QCIF to CIF mixing proposal TD-11 Chairman Agreements and actions (substitute of the meeting report) END Annex 1 to AVC-598R Documents for the Daejeon/Seoul meeting (27 October - 5 November 1993) Normal Documents AVC number MPEG93/??? Pur-pose Title (Source) AVC-578R 880 R Report of the thirteenth Experts Group meeting in Brussels (September 2-10, 1993) - Part I and Part II (Rapporteur) AVC-579R - R Report of the thirteenth Experts Group meeting in Brussels (September 2-10, 1993) - Part III (Rapporteur) AVC-580 N0532 R Fourth Working Draft - Video (WD Editing Committee) AVC-581 - I/D Additional comments on video combining from 4QCIFs to CIF (Bellcore) AVC-582 N0531 R Fourth Working Draft - Systems (WD Editing Committee) AVC-583 - R Meeting report - Part 1 (Working Party 1/15) AVC-584 - R Guidance to the Rapporteur for the study of video coding and systems in ATM and other network environments (Chairman of Working Party 1/15) AVC-585 931 D ATM network adaptation performance parameters (Australian UVC consortium) AVC-586 - R Report of Discussion group on MPEG-2 Systems and ATM (Stuart Dunstan) AVC-587 - D Packetisation of H.221 frames for LANs (Australian UVC consortium) AVC-588 940 P Modification to VBV for VBR in WD is incorrect (AT&T) AVC-589 - P Field trial of H.32X ATM video codec interconnection (Japan) AVC-590 - P Picture format for H.32X (Japan) AVC-591 898 D Comments on vbv_delay description in variable bitrate operation (Japan) AVC-592 - I Bitrate representation for VBR operation for ATM transmission (Japan) AVC-593 - P AAL for hardware verification (Japan) AVC-594 958 D Cell loss correction method for MPEG 2 System Streams transmission (Japan) AVC-595 - D Video and audio communication system for CSMA/CD LAN (NTT) AVC-596 885 I Clarification for the use of VBV for low delay applications (BT) AVC-597 884 P Proposal for modified syntax, semantics and decoding process for spatial scalability (BT) Abstract [???] indicates MPEG Document Number MPEG93/???. AVC-578R [880] Report of the thirteenth Experts Group meeting in Brussels (September 2-10, 1993) - Part I and Part II (Rapporteur) This document records the outcome of the Brussels sole sessions held in July 1993. AVC-579R [-] Report of the thirteenth Experts Group meeting in Brussels (September 2-10, 1993) - Part III (Rapporteur) This document records the outcome of the Brussels joint sessions held in July 1993, covering Requirements, Video, Implementation Study and Systems sub-groups. AVC-580 [N0532] Fourth Working Draft - Video (WD Editing Committee) This document gives frozen specifications for video coding part which were updated at the Brussels meeting. AVC-581 [-] Additional comments on video combining from 4QCIFs to CIF (Bellcore) The second approach to achieve asynchronous video channels by reducing the operational transfer rate in a full capacity is described. An implementation example by use of this second approach is reported. Some clarifications are also given to the misunderstanding contained in the Brussels output report on this matter. It is concluded that the Experts Group should not recommend either of the video combiner and transcoding approaches, but leave the choice to the market since both can co-exist. AVC-582 [N0531] Fourth Working Draft - Systems (WD Editing Committee) This document gives frozen specifications for systems coding part which were updated at the Brussels meeting. AVC-583 [-] Meeting report - Part 1 (Working Party 1/15) This document gives the outcome of the first WP1/15 meeting in this study period which made progress, among other things, in clarifying the standardization plan in the area of audiovisual communication systems. It also gave guidance to the work of this Experts Group which is now in charge of drafting Recommendations for video coding as well as systems aspects. AVC-584 [-] Guidance to the Rapporteur for the study of video coding and systems in ATM and other network environments (Chairman of Working Party 1/15) The work area and the work methods of the Experts Group have been redefined eith the following target Recommendations; H.26X Video coding for ATM environments H.22X Multimedia multiplex and synchronization for ATM environments H.32X Broadband audiovisual communication (or visual telephone?) systems and terminal equipment H.32Y Adaptation of H.320 terminals to B-ISDN H.32Z Adaptation of H.320 terminals to LANs AVC-585 [931] ATM network adaptation performance parameters (Australian UVC consortium) This document discusses performance parameters in ATM network adaptation of real time audio and video signals with respect to delay, error performance, and packing efficiency. "Pipelining" and "user data alignment" modes of operation are considered. Two network adaptation modes of operation are discussed; one is based upon AAL type 3/4 SAR and the other is based on MPEG-2 Systems Transport Stream. It is concluded that the former outperfoms the latter, particularly if the bit rate is low. AVC-586 [-] Report of Discussion group on MPEG-2 Systems and ATM (Stuart Dunstan) Correspondence work after the Brussels meeting is reported which has addressed identifying a suitable interworking point for MPEG-2 systems on packet oriented networks. It is pointed out that a clear statement is required on the use of PES without support of PS or TS. Functionalities and their allocation in the network adaptation is the issue. AVC-587 [-] Packetisation of H.221 frames for LANs (Australian UVC consortium) A means of adapting H.320 terminals for use on packet switched LANs, in which the H.221 frame structure is retained, is discussed with respect to protocol stack, H.221 multiplexed data alignment with the packet, packet size, impact of a packet loss and timing recovery. The advantage of this approach is the maximum use of exiting component/equipment, but the subjective impact of packet loss is unknown, requiring further study. AVC-588 [940] Modification to VBV for VBR in WD is incorrect (AT&T) It is proposed that the definition of vbv_delay and bit_rate for VBR should be reverted back to "3FFFFFFF" and "FFFF", because the current definition can not be satisfied by the encoder. It is reminded that correct operation of a video decoder in the case of VBR can be ensured at the systems layer. AVC-589 [-] Field trial of H.32X ATM video codec interconnection (Japan) In order to make effective the field trial which is planned in the middle of 1995, it is proposed that many members in the Experts Group should give their planned specifications of the experimental codecs for the basis of further discussions. An example of codec specifications is provided as a stimulus for further consideration. AVC-590 [-] Picture format for H.32X (Japan) It is proposed that H.32X picture formats should include respective local formats for high quality intra-regional services and some mandatory common format(s) for inter-regional communications. AVC-591 [898] Comments on vbv_delay description in variable bitrate operation (Japan) It is suggested to add description indicating that the delay needed to start decoding in VBR operation should be calculated from the vbv_delay and bit_rate values and that the illustration should be modified to correspond to a realistic case. It is also raised whether indication to distinguish CBR and VBR is needed, and possible solutions are provided. AVC-592 [-] Bitrate representation for VBR operation for ATM transmission (Japan) Implications of the current definition of bit rate for VBR are considered in the light of ATM network VBR services. It is hinted that traffic descriptors at the user/network interface may be rather loosely coupled with this VBR bit rate definition. AVC-593 [-] AAL for hardware verification (Japan) This document first discusses error strategy for the H.22X/AAL and indicates a choice for a given network QoS in terms of bit error and cell loss characteristics. Then, several alternative solutions for H.22X/AAL are compared regarding packetizing delay, packing efficiency, implementation, error recovery time. Finally two service classes are assumed; one for higher transmission efficiency and easy implementation and another for high quality. In conclusion, it is suggested to take the first service and employ AAL type 5 or AAL type 1 (cell interleave) for the hardware trial being planned. AVC-594 [958] Cell loss correction method for MPEG 2 System Streams transmission (Japan) The following two methods are provided for discussion to deliver TS packets over ATM networks with its alignment with ATM cells; AAL Type 1: use of RS(192,190) and CRC for a group of 47 TS packets AAL new Type: use of RS(4m+4,4m) and CRC for a group of m TS packets AVC-595 [-] Video and audio communication system for CSMA/CD LAN (NTT) Information is provided on an implementation of audiovisual communication system over CSMA/CD LAN which uses H.261 and G.728 source coding but packet multiplex and Internet protocol TCP/IP and UDP/IP. A design of gateway between LAN and N-ISDN is also informed. AVC-596 [885] Clarification for the use of VBV for low delay applications (BT) This document provides information on the use and operation of VBV in low delay mode applications and rationales for use of skipped pictures after a "big picture"; to keep low steady state delay by occasionally allowing temporal distortion. AVC-597 [884] Proposal for modified syntax, semantics and decoding process for spatial scalability (BT) This document provides the syntax, semantics and decoding process used for bitstream exchange for spatial scalability. It is proposed to replace the current WD text with this description. Temporary Documents TD-1 Rapporteur Agenda for the sole sessions TD-2 Rapporteur Available documents for the Daejeon/Seoul meeting TD-3 Rapporteur List of tape demonstrations TD-4 Rapporteur List of open issues - October 1993 TD-5 Rapporteur Network adaptation functions and their allocation to different layers TD-6 S. Okubo Organization of ITU-T SG15 (1993-1996) TD-7 ITU-T SG15 EG Spatial scalability when the base layer includes picture skipping TD-8 ITU-T SG15 EG Decoding start-up algorithm for VBR coded bitstream TD-9 T. Tanaka Clarification for AVC-581 and a comment TD-10 S. Dunstan Report of meeting to discuss ATM Network Adaptation - H.22X/AAL TD-11 ITU-T SG15 EG Use of Packetized Elementary Stream as an interface point TD-12 Rapporteur Draft report of the Daejeon sole sessions END Annex 1 to AVC-632R Documents for the Paris meeting (16-24 March 1994) Normal Documents * Inputs to the joint meeting with SG13 as working documents AVC number MPEG number Pur-pose Title (Source) AVC-598R - R Report of the fourteenth Experts Group meeting in Daejeon and Seoul (October 27 - November 5, 1993) - Part I and Part II (Rapporteur) AVC-599R - R Report of the fourteenth Experts Group meeting in Daejeon and Seoul (October 27 - November 5, 1993) - Part III (Rapporteur) AVC-600 N0659 R CD13818-2 - Video (WG11 Editorial Group) AVC-601 N0658 R CD13818-1 - Systems (WG11 Editorial Group) AVC-602 N0660 R CD13818-3 - Audio (WG11 Editorial Group) AVC-603 - I The teleseminar on workstation and computer networks (INRIA) AVC-604* - I About the ability of AAL type 1 for the transport of MPEG 2 signals (ITU-T SG9) AVC-605 SC29 N710 P Comments on ISO/IEC 13818-1 Systems CD (Australia NB) AVC-606* - D A layer model for H.22x, multimedia multiplex and synchronization for audiovisual communication in ATM environments (KPN, PTT Research - Netherlands) AVC-607 - I Japanese contributions related to H.32X specifications (Japan) AVC-608 - D Terminal specifications for high quality videoconferencing (Japan) AVC-609* - D Multimedia multiplex and AAL for high quality videoconferencing (Japan) AVC-610 - D Terminal specifications for audiovisual communication using WS (Japan) AVC-611* - D Multimedia multiplex/AAL for audiovisual communication using WS (Japan) AVC-612 - D Terminal specifications for broadcasting including CATV (Japan) AVC-613* - D Multimedia multiplex/AAL for broadcasting including CATV (Japan) AVC-614 041 D&P bit_rate field in VBR operation (Japan) AVC-615 044 P Comments for CD13818-2 | Draft Rec. H.262 (Japan) AVC-616* - D Cell loss correction method with low processing delay (Japan) AVC-617* 054 D Cell loss correction method in AAL for the transmission of MPEG 2 Transport packets (Japan) AVC-618* - I&D Issues related to the transmission of MPEG bitstreams over ATM (BT - UK) AVC-619 - D Some H.32X audiovisual terminal issues (Australian UVC consortium) AVC-620 - D Draft skeleton text for H.22X (S. Dunstan) AVC-621 - P Recommendations on preparation of H.22x (IBM and AT&T Communications) AVC-622 039 D&P Evolution of H.22x - Multimedia multiplex to include MPEG-2 systems (IBM) AVC-623 - D Draft skeleton text for H.32X (C-C. Li) AVC-624 - D Draft skeleton text for H.32Y (S. Okubo) AVC-625 - R Status report on the study of network adaptation (Rapporteur) AVC number MPEG number Pur-pose Title (Source) AVC-626 SC29 N710 I Belgian National Body comments on MPEG-2 CD's (BELGACOM) AVC-627 - D General approach to H.32z (UK) AVC-628 071 I Simulation of Phase-Locked Loop for Jittered PCR's (AT&T) AVC-629 - R Status report on AAL1&2 for video signal support (K. Yamazaki, Rapporteur for Q.6/13) AVC-630* - P Inclusion of MPEG TS-layer with jitter compensation in H.22X (KPN, PTT Research - Netherlands) Abstract [nnn] indicates MPEG Document Number MPEG94/nnn. AVC-598R [-] Report of the fourteenth Experts Group meeting in Daejeon and Seoul (October 27 - November 5, 1993) - Part I and Part II (Rapporteur) This document records the outcome of the Daejeon sole sessions held in October 1993. AVC-599R [-] Report of the fourteenth Experts Group meeting in Daejeon and Seoul (October 27 - November 5, 1993) - Part III (Rapporteur) This document records the outcome of the Seoul joint sessions held in November 1993, covering Requirements, Video, Implementation Study and Systems sub-groups. AVC-600 [N0659] CD13818-2 - Video (WG11 Editorial Group) This document contains Video part of CD which was put forward to the SC29 ballot in December 1994. AVC-601 [N0658] CD13818-1 - Systems (WG11 Editorial Group) This document contains Systems part of CD which was put forward to the SC29 ballot in December 1994. AVC-602 [N0660] CD13818-3 - Audio (WG11 Editorial Group) This document contains Audio part of CD which was put forward to the SC29 ballot in December 1994. AVC-603 [-] The teleseminar on workstation and computer networks (INRIA) This document describes a tele-teaching and videoconferencing system using workstations and computer networks including INTERNET, which is now used for tele-seminars and collaborative working. AVC-604 [-] About the ability of AAL type 1 for the transport of MPEG 2 signals (ITU-T SG9) This document provides SG9's opinion that AAL 1 is adequate for the transport of MPEG-2 CBR signals and its workplan that a Rapporteur Group will further examine the relevant contribution attached to this document. AVC-605 [SC29 N710] Comments on ISO/IEC 13818-1 Systems CD (Australia NB) A total of 135 comments are given to improve the text; most of them are editorial nature. Two items are requiring modification of semantics for PES packet stuffing_byte and stream_id table. Attention is drawn to the correction on time stamp equations in the STD description. AVC-606* [-] A layer model for H.22x, multimedia multiplex and synchronization for audiovisual communication in ATM environments (PTT Research) Two versions of detailed layer model for the network adaptation are presented; one with TS layer, the other without it. Objectives are to clarify the options and choices for H.22X in combination with MPEG Systems, to identify appropriate interface points and to provide a basis for the allocation of functions to layers and the specifications for these layers. Necessity of jitter margin specification in the standard is also pointed out. AVC-607 [-] Japanese contributions related to H.32X specifications (Japan) This is a lead paper for the subsequent six documents (AVC-608 to 613) presenting the case study results on typical applications on B-ISDN; high quality videoconferencing, audiovisual communications using work stations and broadcasting including CATV. Terminal specifications and network adaptation are addressed. How to integrate these specifications into a single Recommendation H.32X is pointed out as an issue. AVC-608 [-] Terminal specifications for high quality videoconferencing (Japan) This document describes H.32X mandatory and optional specifications covering various aspects such as applications, input/output equipment, number and kind of different media, control channel, video coding, audio coding, network adaptation, multipoint, multimedia synchronization, error handling. It is raised that a hierarchical structure of terminal classes is necessary; CIF/QCIF, ITU-R BT.610 and HDTV. AVC-609* [-] Multimedia multiplex and AAL for high quality videoconferencing (Japan) VBR operation for real time audiovisual communication (high quality videoconferencing) is discussed in terms of delay, packing efficiency and error resilience. It is stressed that multiplexing interval time is restricted for low delay operation, leading to a conclusion that the delay is not a decisive factor for the AAL choice. Several AAL solutions based on existing AAL 1, 3/4 and 5 are provided and compared in packing efficiency and error resilience. The choice depends on the network QoS. AVC-610 [-] Terminal specifications for audiovisual communication using WS (Japan) This document discusses the configuration of AV communication terminal using work stations. Some functions such as N-ISDN interworking, timebase recovery, FEC are made optional taking into account of network environments and application characteristics. AVC-611* [-] Multimedia multiplex/AAL for audiovisual communication using WS (Japan) This document presents a case study outcome for a class of application, audiovisual communication using work stations. Considering the requirements of delay, efficiency, picture quality, it is concluded that a combination of PES and AAL 5 is the most desirable choice. AVC-612 [-] Terminal specifications for broadcasting including CATV (Japan) This document discusses terminal specifications for the TV distribution services which are characterized by that the terminals are classified into CTV and HDTV classes, that the video data flow is one directional and that the decoded picture format will be restricted to the local format. AVC-613* [-] Multimedia multiplex/AAL for broadcasting including CATV (Japan) This document discusses an appropriate network adaptation for the TV distribution application. Assuming that MPEG Systems TS is used for this type of service, a solution of TS packets mapped on some AAL with FEC is concluded. It is also suggested that the network adaptation specifications may be classified according to the number of programs per TS or the bit rate. AVC-614 [041] bit_rate field in VBR operation (Japan) This document intends to clarify the VBR operation in H.262|ISO/IEC 13818-2 based on the CD texts, raising the following questions; bit_rate values that can be written when vbv_delay = FFFF, wording for the bit_rate semantics, transport buffer size being not sufficient, and consideration of start-up delay for the multiplex buffer. As to the bit_rate values in VBR, it is proposed to apply the same maximum values as those for CBR. AVC-615 [044] Comments for CD13818-2 | Draft Rec. H.262 (Japan) Editorial improvements with suggested wording as well as editorial corrections to Video CD (WG11 N0659, AVC-600) are listed. AVC-616* [-] Cell loss correction method with low processing delay (Japan) A closed form of cell interleaving matrix is provided for VBR applications. Its feature is that the user data can be transmitted in unit of 704 bytes. Detailed comparison of performance between the agreed open forma and this closed form is tabled. AVC-617* [054] Cell loss correction method in AAL for the transmission of MPEG 2 Transport packets (Japan) A cell loss/bit error correction method is provided to facilitate TS packets delivery over ATM. This method assembles 47 TS packets and add 2x47 bytes CRC and 2mx47 bytes RS parity, achieving alignment of TS packets and ATM cells, use of existing AAL 1 protocol and low delay. AVC-618* [-] Issues related to the transmission of MPEG bitstreams over ATM (BT - UK) To meet the urgent user requirement that MPEG-2 coded materials be delivered through ATM networks, three issues are raised which need solutions; common access point, support for MPEG timing, and an AAL for MPEG streams. Some candidate solutions are discussed with conclusions that TS packets be the prime interface point and that the support of jitter compensation at each ATM node is impractical and thus a generalized AAL for real-time VBR transmission be pursued. AVC-619 [-] Some H.32X audiovisual terminal issues (Australian UVC consortium) This document raises and discusses the following system aspect issues; 1) protocol configuration for the network adaptation, providing "Video and Audio CS", 2) PES multiplexing capacity and its relevance to H.22X functions when AAL is used and jitter compensation capability of AAL 1, 3) allocation of timebase recovery function to the "Video and Audio CS", 4) impacts of buffer location in the terminal on the rate control. AVC-620 [-] Draft skeleton text for H.22X (S. Dunstan) A list of sections and key items is given for H.22X. Some discussion items are also listed; definition of SAP at the application/H.22X boundary, inclusion of encryption function in H.22X, use of PES or PS as protocol, necessity of acknowledgment in H.22X procedures. AVC-621 [-] Recommendations on preparation of H.22x (IBM and AT&T Communications) This document presents the T1A1 view regarding the relationship between MPEG-2 Systems and the network adaptation, which supports to accelerate the development of the network adaptation of audiovisual signals to ATM transport by possibly adding H.22X specific functions that are not part of MPEG-2 Systems. AVC-622 [039] Evolution of H.22x - Multimedia multiplex to include MPEG-2 systems (IBM) After a brief review of H.22x (multimedia multiplex in H.32x terminal equipment) and MPEG-2 status in Study Group 15, this paper suggests that Study Group 15 capitalize on the MPEG-2 Systems Layer as a common enabling technology for both multimedia conferencing and video distribution. It concludes with a specific recommendation of adopting MPEG-2 systems as a fundamental component of H.22x. AVC-623 [-] Draft skeleton text for H.32X (C-C. Li) A list of sections and key items is given for H.32X. AVC-624 [-] Draft skeleton text for H.32Y (S. Okubo) A list of sections and key items is given for H.32Y including some questions. AVC-625 [-] Status report on the study of network adaptation (Rapporteur) This status report summarizes the activities of the SG15 Experts Group on the study of network adaptation (projected Rec. H.22X "multimedia multiplex and synchronization") and audiovisual signal transport AAL. AVC-626 [SC29 N710] Belgian National Body comments on MPEG-2 CD's (BELGACOM) This document lists comments to Systems and Video CD from Belgian National Body of SC29. AVC-627 [-] General approach to H.32z (UK) After a review of audio coding, video coding, multiplexing, transmission and call set up signalling for LAN environments, it is concluded that the best approach is to provide the equivalence of ISDN transmission over the LANs and make the minimum of modifications to H.320. AVC-628 [071] Simulation of Phase-Locked Loop for Jittered PCR's (AT&T) Simulation results are reported for the PCR recovery phase lock loop in terms of frequency error, frequency change step and phase error with parameters of initial frequency offset, initial phase offset, and peak-to-peak jitter. The PCR rate and oscillator update rate are both set to 10 Hz. The results show that the required extra buffering is 3 ms for timebase recovery plus 1 ms for accommodating the jitter, hence the timebase recovery in ATM environments is encouraging. It is concluded that more contributions on the expected performance of networks and the needed purity of the recovered clock are required to allow design of an optimized PLL. AVC-629 [-] Status report on AAL1&2 for video signal support (K. Yamazaki, Rapporteur for Q.6/13) This status report summarizes the activities of SG13 on the study of AAL 1 and AAL 2 (Rec. I.363). AVC-630 [-] Inclusion of MPEG TS-layer with jitter compensation in H.22X (KPN, PTT Research - Netherlands) Based on the discussion contained in AVC-606, the following is proposed; 1) to include the MPEG2 TS-layer in H.22X under the condition that the MPEG2 TS-layer shall handle timing jitter introduced by the network on an end-to-end basis, without time stamp correction in the network, 2) to study and specify jitter margins that clock recovery systems of H.22X shall meet and that shall be supported by the network on the User-Network Interface, 3) to liaise with ISO-MPEG to reach a common TS-layer for H.22X and other applications. Temporary Documents Number Source Title TD-1 Rapporteur Agenda for the sole sessions TD-2 Rapporteur Available documents for the Geneva/Paris meeting TD-3 Rapporteur H-series audiovisual terminals in different network environments TD-4 Rapporteur Correspondence on STC recovery in ATM environments TD-5 Rapporteur Network adaptation functions and their allocation TD-6 Rapporteur Memorandum on the outcome of the Geneva meeting TD-7 Rapporteur Functions of network adaptation TD-8 AT&T ATM network adaptation for MPEG-based audiovisual communication systems TD-9 S. Dunstan Report of discussion on H.22X/AAL TD-10 Telia Research Comparison of alternative ATM mappings for MPEG-2 TD-11 S. Okubo, K. Yamazaki Draft report of the joint meeting of SG13 AAL Type 1&2 Group and SG15 Experts Group for ATM Video Coding TD-12 Rapporteur Effects of jitter in recovered timebase TD-13 Sun Micro. MPEG System stream encapsulation in AAL5 TD-14 K. Joseph A rational ATM interface for AMS TD-15 T. Bruner and M. Schwartz Proposed requirements for a real time transport service TD-16 S. Dunstan Report of second discussion on H.22X/AAL TD-17 H. Radha Performance parameter assumptions TD-18 D. Schinkel List of correspondents TD-19 R. ter Horst Draft input proposal for MPEG meeting TD-20 Rapporteur Draft meeting report for the sole sessions in Paris END Annex 1 to AVC-673R Documents for the Grimstad meeting (13-22 March 1994) Normal Documents AVC number MPEG number Pur-pose Title (Source) AVC-631R - R Report of the joint meeting with SG13 AAL 1&2 Group in Geneva (14 March 1994) and liaison statement from SG13 (Rapporteur) AVC-632R - R Report of the fifteenth Experts Group meeting in Paris (16-25 March 1994) - Part I and Part II (Rapporteur) AVC-633R - R Report of the fifteenth Experts Group meeting in Paris (16-25 March 1994) - Part III (Rapporteur) AVC-634 - R AAL1 circuit emulation (Rapporteur for Q.6/13, K. Yamazzaki) AVC-635 - R ATM performance assumptions (Experts Group) AVC-636 - P Consideration of loss priority between H.22X (Multimedia multiplex including MPEG-2 Systems) and AAL type 1/2 (Korea) AVC-637 - I IVS Baseline Document - March 1994 (SG13) AVC-638 - R Meeting report of WP1/15 (Chairman of WP1/15, M. Yamashita) AVC-639 - R Sixth progress report of The Experts Group for Video Coding And Systems in Atm and Other Network Environments (Rapporteur, S. Okubo) AVC-640 - D Correspondence between Rapporteurs for Q.8/10 (B. DeGrasse) and Q.2/15 (S. Okubo) AVC-641 - D Considerations for H.24X - Communication Procedures for Multimedia on ATM (Rapporteur for Q.3/15; N.D. Kenyon) AVC-642 94/166 I Position paper on MPEG Systems and ATM (A. MacInnis, S. Okubo) AVC-643R - R Report of the Systems Adhoc and WG11 meetings held in Atlanta (ITU-T EG Representatives; G. Franceschini, S. Okubo) AVC-644 N0721 R Darft ITU-T Rec. H.222.0|ISO/IEC 13818-1 Systems (Editor) AVC-645 N0702 R Darft ITU-T Rec. H.262|ISO/IEC 13818-2 Video (Editor) AVC-646 94/183 P Increase of frame rate from 30 to 60 Hz in Main Level (ML) (NTR) AVC-647 94/253 P Fast timing recovery in the presence of cell delay jitter (AT&T) AVC-648 - P Expanding the current scope of H.32Z (Tampere University of Technology, Bitfield) AVC-649 - D Real-Time Transport Protocol in H.32Z Systems in ATM and Other Packet-Switched Computer Networks (Tampere University of Technology) AVC-650 - D Technical Issues concerning Real-Time Protocol in H.32Z Systems n ATM and Other Packet-Switched Computer Networks (Tampere University of Technology, Bitfield) AVC-651 - I Report on preliminary experiments using H.320 codecs over ATM networks (BT) AVC-652 - R Report of the first meeting of the JCG on AVMMS (Chairman of JCG/AVMMS, M. Yamashita) AVC-653 - P Comments for Editor's notes in H.32Y draft recommendation (Japan) AVC-654 94/230 P Editorial comments for Draft Rec. H.222.0 | ISO/IEC 13818-1 (Japan) AVC-655 94/225 P/D Communication procedure for H.222.1 (Japan) AVC-656 94/214 P/D Necessary provision for applying H.222.0 to the H.32X terminals (Japan) AVC-657 - D Consideration on error correction functionality in H.222/AAL (Japan) AVC-658 - I A study of the H.22X interaction with the AAL for the ATM transmission of TS packets (Japan) AVC-659 - I A plan of H.32X hardware interconnection experiment in Japan (Japan) AVC-660 - P Darft H.22X (Editor, Stuart Dunstan) AVC-661 - P Draft H.32X (Editor, Chia-Chang Li) AVC-662 - P Draft H.32Y (Editor, Sakae Okubo) AVC-663 - P Draft H.32Z (Editro, Geoff Morrison) AVC-664 94/254 I/D Multiplex at ATM layer with H.222 (KPN-PTT) AVC number MPEG number Pur-pose Title (Source) AVC-665 94/220 P Closed caption in ITU-T H.262|ISO 13818-2 (Bellcore) AVC-666 - D/P H.32X Communication Modes, Terminal Types, and Interwroking Scenarios between H.32X Terminals (AT&T) AVC-667 - D/P Inter-operability between B-ISDN H.32X and N-ISDN H.320 Terminals (AT&T) AVC-668 - D/P Video Conferencing Control and Indication Signals for H.262 (AT&T) AVC-669 94/228 I ITU-T Approval of Common Text Recommendations | International Standards (Rapporteur) AVC-670 94/227 I Patent Statements and Information for Draft ITU-T Rec. H.262 | ISO/IEC 13818-2 (Rapporteur) AVC-671 - P Considerations for H.32Z Endpoints (AT&T) AVC-672 - I Cell Delay Variation (CDV) in ATM Networks (AT&T) Abstract [nnn] indicates MPEG Document Number. AVC-631R [-] Report of the joint meeting with SG13 AAL 1&2 Group in Geneva (14 March 1994) and liaison statement from SG13 (Rapporteur) This document contains a report of the joint discussion by the experts of SG13 AAL1&2 and SG15 ATM video coding and systems which took place on March 14, 1994. It also contains SG13 liaison statements to SG15, SG9 and MPEG on video signal transport in ATM networks. AVC-632R [-] Report of the fifteenth Experts Group meeting in Paris (16-25 March 1994) - Part I and Part II (Rapporteur) This document records the outcome of the Paris sole sessions held in March 1994, summarizing the discussion and identifying action items. AVC-633R [-] Report of the fifteenth Experts Group meeting in Paris (16-25 March 1994) - Part III (Rapporteur) This document records the outcome of the Paris joint sessions held in March 1994, covering Requirements, Video and Systems sub-groups. AVC-634 [-] AAL1 circuit emulation (Rapporteur for Q.6/13, K. Yamazzaki) Clarification is given to "circuit emulation" which was raised at the Paris meeting (6.4/AVC-632R) in terms of circuit transport Vs video signal transport. Services provided by N-UNI, B-UNI, Interworking Function and TA are also clarified. AVC-635 [-] ATM performance assumptions (Experts Group) Best available information on ATM performance assumptions are tabulated for the worst, average case and worst case of CLR, BER, end-to-end delay, CDV etc. This information is intended to assist the network adaptation study as decided at the Paris meeting (8.2.2/AVC-632R). AVC-636 [-] Consideration of loss priority between H.22X (Multimedia multiplex including MPEG-2 Systems) and AAL type 1/2 (Korea) This document proposes to define a priority primitive between H.22X and AAL Type1/2 for the MPEG-2 Transport Streams with transport_priority. This priority primitive is mapped onto CLP bit in the ATM layer. AVC-637 [-] IVS Baseline Document - March 1994 (SG13) This is the final version of the IVS Baseline document which has served to provide a common basis for the ongoing study of IVS by SG13 and other groups. It describes objectives, responsibility of each group, range of services to be covered and staged approach for evolution of service integration. It also includes several annexes to overview the current status of the study on both of network and service aspects. AVC-638 [-] Meeting report of WP1/15 (Chairman of WP1/15, M. Yamashita) This is the Chairman's report of the Working Party 1/15 meeting held in May 1994. Materials related to broadband audiovisual matters are either attached to this document or issued as separate AVC-numbered documents (AVC-636,639,640). AVC-639 [-] Sixth progress report of The Experts Group for Video Coding And Systems in Atm and Other Network Environments (Rapporteur, S. Okubo) This document provides a progress report to Working Party 1/15, which covers the two meetings of the Experts Group (October-November 1993 and March 1994) and summarizes major achievements toward defining H.262, H.22X, H.32X/Y/Z. It also lists particular items which need consideration of WP1/15; 1) intellectual property processing for H.262, 2) commitment in hardware trials, 3) advice on open issued for Draft Recommendations, 4) Common Text approach to MPEG-2 Systems, 5) DSM-CC activities in MPEG, 6) editorial corrections to H.262, 7) guideline for the interaction with The ATM Forum, 8) initiation of H.24X work. AVC-640 [-] Correspondence between Rapporteurs for Q.8/10 (B. DeGrasse) and Q.2/15 (S. Okubo) SG8 comments on the H.32X protocol model that use of different AAL thus different VC is more appropriate for exchange of telematic information and high-level audio-video control. Views of SG15 are also provided which was generated during its May 1994 meeting. AVC-641 [-] Considerations for H.24X - Communication Procedures for Multimedia on ATM (Rapporteur for Q.3/15; N.D. Kenyon) Rapporteur for Q.3/15 provides some hints on the communication procedures for the broadband audiovisual/multimedia terminal, reflecting the lessons obtained through the development of H.242 for the N-ISDN terminal. Possible extensions to the H.242 procedures are; 1) capabilities to encode, 2) no need for indication of multiplex structure this time, 3) expression of mode preference from the receiving end, 4) integration of outband and inband procedures, 5) handling of ATM fault conditions, 6) unified handling of data, 7) consideration of multipoint from the outset, 8) interworking with ISDN and PSTN multimedia terminals as a mandatory requirement, 9) physical channel for control, 10) choice of control protocol harmonized with other applications. AVC-642 [94/166] Position paper on MPEG Systems and ATM (A. MacInnis, S. Okubo) This document intends to clarify the relationship between the MPEG Systems and ATM with their overviews and techniques to cope with particular characteristics of ATM - cell delay variation. It is shown that cell delay variation of the network can be reduced by either of the network specific solution or the integrated decoder solution. AVC-643R [-] Report of the Systems Adhoc and WG11 meetings held in Atlanta (ITU-T EG Representatives; G. Franceschini, S. Okubo) The outcome of the Atlanta meetings of the Adhoc Group and WG11 is reported with focus on the ATM related organizational and technical matters. AVC-644 [N0721] Darft ITU-T Rec. H.222.0|ISO/IEC 13818-1 Systems (Editor) This draft was produced at the MPEG meeting in Atlanta for DIS balloting. AVC-645 [N0702] Darft ITU-T Rec. H.262|ISO/IEC 13818-2 Video (Editor) This draft was produced at the joint meeting in Paris for DIS balloting. AVC-646 [94/183] Increase of frame rate from 30 to 60 Hz in Main Level (ML) (NTR) To allow low bitrate and high temporal resolution applications and low delay applications requiring high temporal resolutions within the resource for the current Main Level decoder, increase of frame rate bound from 30 to 60 is proposed. Newly covered formats include (720x288x50), (360x288x50), (480x240x60), (544x288x50), etc. AVC-647 [94/253] Fast timing recovery in the presence of cell delay jitter (AT&T) This document presents a method of speeding up the timebase recovery where arrival time of each cell is monitored and compared with estimated arrival time which is computed from the values of program_mux_rate (in case of PS) or piecewise_rate (in case of TS) and the encoder clock reference (SCR or PCR) and adjusted for the effect of packing the clock reference information into cell, then the arrival jitter is fed back to the timebase recovery PLO. AVC-648 [-] Expanding the current scope of H.32Z (Tampere University of Technology, Bitfield) This document proposes a framework of H.32Z which consists of; 1) use of the word "Packet Switched Computer Network (PSCN)" instead of "LAN", 2) use of Real Time Protocol (RTP) in PSCN, 3) support of the best effort computer networks in addition to the guaranteed bandwidth networks, 4) non-use of H.221/H.22X in PSCN connections, they are removed/regenerated at the PSCN-ISDN gateway, 5) adoption of RTP as ITU-T Recommendation H.22Z. AVC-649 [-] Real-Time Transport Protocol in H.32Z Systems in ATM and Other Packet-Switched Computer Networks (Tampere University of Technology) This document provides supporting material to the proposal in AVC-648; 1) overview and status of RTP, 2) timing model without bandwidth reservation, 3) packet routing in PSCN, 4) multicast addresses for data transportation. As a conclusion, it is argued that installed base of computers be used for audiovisual service even if its quality may be slightly worse than the one obtained through the guaranteed bandwidth network. AVC-650 [-] Technical Issues concerning Real-Time Protocol in H.32Z Systems n ATM and Other Packet-Switched Computer Networks (Tampere University of Technology, Bitfield) This document addresses several aspects of the RTP use in PSCN environments as support of the proposed framework in AVC-648; 1) ISDN-PSCN interworking, 2) ISDN and PSCN address conversion, 3) mapping of H.320 on RTP, 4) mapping of RTP on PSCN. AVC-651 [-] Report on preliminary experiments using H.320 codecs over ATM networks (BT) This document reports on connecting existing H.320 terminals between Ipswich and London through an ATM Virtual Path where AAL1 adaptation is carried out between G.703/704 2 Mbit/s connection and the ATM switch. Adaptive clock method is employed and 3 Mbit/s ATM channels are used not to invoke policing. It is concluded that the quality of link and coded pictures is very good. AVC-652 [-] Report of the first meeting of the JCG on AVMMS (Chairman of JCG/AVMMS, M. Yamashita) This meeting was represented by SGs 1,3,7,8,9,11,12 and 15. Among other things, Questions and work plans of relevant SGs, relationship with organizations outside of ITU-T, study of Interactive Multimedia Services, profiling multimedia services were discussed. AVC-653 [-] Comments for Editor's notes in H.32Y draft recommendation (Japan) This document provides replies to some of the editor's questions, particularly to the questions of AAL1 parameters, error handling and call control. AVC-654 [94/230] Editorial comments for Draft Rec. H.222.0 | ISO/IEC 13818-1 (Japan) Comments of editorial nature are given to the DIS version of "Systems" specifications. (AVC-644). AVC-655 [94/225] Communication procedure for H.222.1 (Japan) This document discusses communication control procedures which handle negotiation at the beginning of communication and mode switching during communication. It also lists items to be negotiated and C&I signals for audiovisual communications. Since a dedicated control channel is required, assignment of PID (for TS) and stream_id in the PES header is proposed. Furthermore, an outline of communication procedure is illustrated for further discussion. For distinction of PS and TS as a multiplex method, us of LLC/HLC in the outband and sending a liaison statement to SG11/13 is suggested. Finally, necessary study for setting up a bi-directional control channel for asymmetric communication is raised. AVC-656 [94/214] Necessary provision for applying H.222.0 to the H.32X terminals (Japan) This document proposes new entries to the definition of elementary streams, stream_id in the PES header, stream_type in Program Stream Map and Program Map Table, descriptor_tag in the stream descriptors in H.222.0 to accommodate ITU-T audio/video/data/control channels. It also discusses dynamic mode changes during transmission whose indication should be synchronous with the mode change. Use of data_alignment_indicator together with the PSM/PMT descriptors is proposed; this is also applicable to video frame synchronous C&I. For this purpose, a new entry to the audio_data_stream_alignment is proposed. Finally, this document points out a packetizing delay management problem involved in the low bit rate ITU-T audio coding. AVC-657 [-] Consideration on error correction functionality in H.222/AAL (Japan) This document discusses necessity of bit error/cell loss correction against the network performance assumptions given in AVC-635. For a 6 Mbit/s user information bit rate, it is concluded from the calculation of mean error free time that bit error correction is necessary for all the scenarios while cell loss correction becomes necessary only for the worst case scenario. Several error correction alternatives are illustrated; 1) use of the short interleaver in AAL1, 2) FEC in the H.222.1 specific layer with/without its own framing header, 3) FEC for the TS packet in H.222.1 specific layer/AAL2 with/without alignment with cell boundaries, 4) interleaver for 47 TS packets in AAL2. It is also argued that error detection in AAL5 and bit error correction in a higher layer do not match well. AVC-658 [-] A study of the H.22X interaction with the AAL for the ATM transmission of TS packets (Japan) This documents provides two examples of primitive parameters to be defined between the H.22X and AAL when TS packets are delivered through the ATM network; one for modified AAL1 where every TS packet is mapped onto 4 ATM cells, the other for AAL5 where 2 TS packets are mapped onto 8 ATM cells. Support of packet priority and error indication are considered. AVC-659 [-] A plan of H.32X hardware interconnection experiment in Japan (Japan) This document provides for information on a Japan plan of H.32X hardware verification testing which is going to be carried out mid 1995. It describes objectives, time schedule, testing environments, test items as well as several points which should be decided to specify the experimental hardware. AVC-660 [-] Darft H.22X (Editor, Stuart Dunstan) AVC-661 [-] Draft H.32X (Editor, Chia-Chang Li) AVC-662 [-] Draft H.32Y (Editor, Sakae Okubo) AVC-663 [-] Draft H.32Z (Editro, Geoff Morrison) These documents contain drafts which reflect discussion at the Paris meeting and subsequent correspondence. Many open issues are indicated in form of editor's comments. AVC-664 [94/254] Multiplex at ATM layer with H.222 (KPN-PTT) This document discusses use of multiple VCs for different elementary streams in a program or different programs in a TS. Specific requirements for H.222.1 to support this are; 1) combining the data from different VC's into a logical valid TS or PS for the target H.222.0 decoder, 2) compensation of the transmission delay differences between the VC's, 3) reduction of cell delay variations between the VC's to a jitter that is acceptable for the target H.222.0 decoder. As a conclusion, it is suggested to define a conformance point at the H.222.1/AAL service boundary for this multiple VC configuration. AVC-665 [94/220] Closed caption in ITU-T H.262|ISO 13818-2 (Bellcore) This document proposes to standardize a mechanism to carry closed caption information which is tightly synchronized with the picture data. The specifications should include location, (de)cipher and other necessary elements. As to the location, use of the user_data in the picture header of ITU-T Rec. H.262|ISO/IEC 13818-2 is proposed as is done in the Grand Alliance HDTV approach. AVC-666 [-] H.32X Communication Modes, Terminal Types, and Interwroking Scenarios between H.32X Terminals (AT&T) This document provides a framework for the work on H.32X communication modes which consist of Video Codec Capability (VCC), Audio Codec Capability (ACC), and Network Adaptation Capability (NAC) with distinction between the transmit end (TE) and receive end (RE) characteristics. It also provides a strawman proposal for H.32X communication modes, terminal types and interworking scenarios which are based on the discussion in AVC-608,610,612; Types A,B,C are defined according to the picture format class (CIF, 601, HDTV). AVC-667 [-] Inter-operability between B-ISDN H.32X and N-ISDN H.320 Terminals (AT&T) H.32X support of H.320 capabilities are discussed and the following is proposed among other things; 1) at minimum two Service Channels, namely transfer rate up to 2x64 kbit/s, 2x384 kbit/s, 1920 kbit/s and their restricted network versions, 2) audio coding of G.711, G.722 and G.728, 3) H.261 with CIF and QCIF formats and 1/29.97 minimum Picture Interval, 4) LSD channel. The conclusion is tabulated with indication of "Mandatory" or "Optional' for all the H.320 capabilities. AVC-668 [-] Video Conferencing Control and Indication Signals for H.262 (AT&T) This document proposes that we pay a special attention to the transmission of C&I signals which are tightly coupled with the video pictures. Four alternative transmission methods are provided for urgent consideration; 1) a separate (logical) channel, 2) user_data or extension_data within the H.262 video sequence header, 3) PES_extension field within the PES packet header, 4) extra_information_picture field of the H.262 picture header. AVC-669 [94/228] ITU-T Approval of Common Text Recommendations | International Standards (Rapporteur, The ITU-T approval process till the publication of the common text MPEG-2 standards (ITU-T Rec. H.222.0|ISO/IEC 13818-1 and ITU-T Rec. H.262|ISO/IEC 13818-2) is tabulated. Requests for cooperation are also described; handling of comments to the DIS version, facilitating to make delta documents for the February 1995 meeting of SG15 and collection of patent statements and information. AVC-670 [94/227] Patent Statements and Information for Draft ITU-T Rec. H.262 | ISO/IEC 13818-2 (Rapporteur) This document summarizes the submission of patent licensing policy statements and information on relevant patens by the patent holders. As a conclusion, cooperation of the ITU-T and ISO/IEC JTC1 members are appreciated and further cooperation AVC-671 [-] Considerations for H.32Z Endpoints (AT&T) Noting that non-guaranteed bandwidth LANs are critical to the success of H.32Z, the following is suggested; 1) splitting H.32Z into two parts - one for guaranteed bandwidth LANs, the other for non-guaranteed bandwidth LANs, 2) use of RTP from the IETF for the latter part of H.32Z. AVC-672 [-] Cell Delay Variation (CDV) in ATM Networks (AT&T) This document (1) emphasizes the standardized CDV parameter in ITU-T Recommendation I.356, (2) summarizes work for CDV characteristics to date, (3) comments on the independence of delay between successive links in an end-to-end connection, and (4) presents some preliminary simulation results on the delay characterization in ATM networks. It is concluded that a value of equal to 350 service times (service time = cell transmission time) as the 10-10 th quantile point of the delay distribution is anticipated for a maximum of 20 switches, muxes and cross connects, giving a CDV of 0.96 milliseconds for 156 Mbit/s trunks. Temporary Documents TD-1 Rapporteur Agenda for the sole sessions TD-2 Rapporteur Available documents for the Grimstad meeting TD-3 G. Franceschini E-mail regarding VBR TD-4 G. Franceschini Support of VBR Real Tome services in the AAL TD-5 Rapporteur Draft summary of discussion on Wednesday TD-6 SG8 Liaison statement to Study Group 15 (Q.2/15) on B-ISDN audiographic and audiovisual conferencing on ATM TD-7 AVC Experts Group Support of ITU-T Control and Indication Signals TD-8 H. Radha Summary of H.32Y discussion and H.320/H.32X interoperability issues TD-9 G. Morrison Excerpt from IEEE 802.9a Draft Standard TD-10 S. Dunstan Summary of discussion on "H.22X and H.222.0", item 5 of TD1 TD-11 Rapporteur Draft report of the sole sessions in Grimstad END Annex 1 to AVC-707R Documents for the Singapore meeting (1-11 November 1994) Normal Documents AVC number MPEG number Pur-pose Title (Source) AVC-673R - R Report of the sixteenth Experts Group meeting in Grimstad(13-22 July 1994) - Part I and Part II (Rapporteur) AVC-674R - R Report of the sixteenth Experts Group meeting in Grimstad(13-22 July 1994) - Part III (Rapporteur) AVC-675 - R Liaison statement to Study Group 15 (Q2/15) on B-ISDN audiographic and audiovisual conferencing on ATM (SG8 - Q.10/8) AVC-676 - R List of open issues - 16 September 1994 (Rapporteur) AVC-677 - P Multimedia System Control: a proposal for H.24P and H.24X (Rapporteur for Q.3/15) AVC-678 - I&D Computer Infrastructure Implications on AVC Function Placement (IBM) AVC-679 - I Video distribution using CBR MPEG-2 over AAL5 (IBM) AVC-680 - P Draft H.222.1 (Editor, Stuart Dunstan) AVC-681 - P Draft H.32X (Editor, Chia-Chang Li) AVC-682 - P Draft H.32Y (Editor, Hayder Radha) AVC-683 - P Draft H.32Z (Editor, Geoff Morrison) AVC-684 - I Report on BT/France Telecom H.320 codec test over ATM networks (UK) AVC-685 - I Report on European progress on AALs for Class A and B services (UK) AVC-686 - P An AAL for Class B services (BT) AVC-687 94/332 P Comments on Draft ITU-T Rec. H.262|ISO/IEC 13818-2 (Rapporteur) AVC-688 94/331 P Comments on Draft ITU-T Rec. H.222.0|ISO/IEC 13818-1 (Rapporteur) AVC-689 - I Reduction of the bit-rate of compressed video while in its coded form (BT Labs) AVC-690 - I Packet video transport in ATM networks with single-bit feedback (AT&T) AVC-691 94/348 P Clarification of descriptor usage (Japan) AVC-692 - P Proposal for ITU-T_stream_descriptors (Japan) AVC-693 94/346 P Request for ITU-T specific stream_id in MPEG2 System (Japan) AVC-694 94/347 D Integration of video frame synchronous C&I in DSM-CC (Japan) AVC-695 - D Consideration of H.222.0 Transport Stream as multimedia multiplexing for audiovisual communications (Japan) AVC-696 - I An example of call setup procedure in an H.32Z terminal (Japan) AVC-697 - D A study on use of multiple VCs (Japan) AVC-698 - D&P Mandatory H.320 interworking modes of operation for H.32X (Japan) AVC-699 - D&P Protocol model for H.32X terminal (Japan) AVC-700 - D Consideration on the optional use of AAL error correcting function at H.32X decoder (Japan) AVC-701 - P Specification of H.32X hardware for the interconnection experiment (Japan) AVC-702 - D Terminal to terminal signalling in H.32X (Siemens) AVC-703 - P Multiplexing protocols for H.222.1 (Siemens) AVC-704 - R Correspondence with Rapporteurs of SG13 and SG11 (Rapporteur) AVC-705 - P Use of AAL 5 for Carrying CBR MPEG-2 TS for video-on-demand applications (AT&T, Bellcore, IBM, MCI) AVC-706 - I ATM Forum Audiovisual and Multimedia Services (IBM) Abstract [94/nnn] indicates MPEG Document Number. AVC-673R [-] Report of the sixteenth Experts Group meeting in Grimstad(13-22 July 1994) - Part I and Part II (Rapporteur) This document records the outcome of the Grimstad sole sessions held in July 1994, summarizing the discussion and identifying action items. AVC-674R [-] Report of the sixteenth Experts Group meeting in Grimstad(13-22 July 1994) - Part III (Rapporteur) This document records the outcome of the Grimstad joint sessions held in July 1994, covering Requirements, Video and Systems sub-groups. DSM sub-group discussions are also included. AVC-675 [-] Liaison statement to Study Group 15 (Q2/15) on B-ISDN audiographic and audiovisual conferencing on ATM (SG8 - Q.10/8) This document provides an SG8 view regarding the transmission of audiographic conferencing signals that the T.120 series protocols should run on a dedicated VC bypassing the H.222.1 module. Use of AAL5, which is common with the signalling, is advocated. AVC-676 [-] List of open issues - 16 September 1994 (Rapporteur) This document lists open issues which were identified until after the Grimstad meeting. They are classified into categories of "network adaptation", "video coding and VBR", "AV terminals and systems", "miscellaneous". Relevant projected H-series Recommendations are also listed in respective items. AVC-677 [-] Multimedia System Control: a proposal for H.24P and H.24X (Rapporteur for Q.3/15) This paper makes a proposal, for further consideration, on the audiovisual communication procedures in the packet based transmission environments. It draws on the experience of H.242, but seeks to avoid the deficiencies thereof: there are transmit-capabilities as well as receive-caps (H.242 had only the latter); multiple audio and video streams and other data can be declared, and the capsets are shorter. There are no commands (on the assumption that audio, video and data have their own headers), but there are content indicators, and one end-point can control what is sent to it by means of mode requests. The proposal is based on variable-length (ILC) messages. Call control procedures for ATM are also provided. AVC-678 [-] Computer Infrastructure Implications on AVC Function Placement (IBM) After examining four system configuration alternatives for a typical computer system which serves for audiovisual multimedia services, it is discussed that the end-to-end QOS that must be maintained for multimedia communication is from codec-to-codec, hence jitter removal should be done only once and must accommodate all sources of jitter between the source of the MPEG-2 stream and the target codec. As a conclusion, it is proposed that jitter removal should be identified as an H.222.1 specific function and performed by the codec. AVC-679 [-] Video distribution using CBR MPEG-2 over AAL5 (IBM) This document provides a reference configuration for the stored CBR MPEG-2 video distribution over ATM. It identifies H.222.1 specific functions as 1) mapping of several TS packets onto an AAL5 SDU, 2) jitter removal and timebase recovery which are implementation specific, thus need not standardization. The document also identifies Q.2931 signalling requirements as 1) asymmetrical QOS and bandwidth, 2) H.222.1 profile, 3) new multimedia information elements such as CBR/VBR, mapping between TS packets and AAL SDU, content and service selection request correlation ID. It is also mentioned that the acceptable UNI-UNI end-to-end delay can be several hundred milliseconds for video distribution. AVC-680 [-] Draft H.222.1 (Editor, Stuart Dunstan) AVC-681 [-] Draft H.32X (Editor, Chia-Chang Li) AVC-682 [-] Draft H.32Y (Editor, Hayder Radha) AVC-683 [-] Draft H.32Z (Editor, Geoff Morrison) These documents contain updated drafts which reflect discussion at the Grimstad meeting and subsequent correspondence. Many open issues are indicated in form of editor's comments. AVC-684 [-] Report on BT/France Telecom H.320 codec test over ATM networks (UK) This document reports on the success of connecting two different H.320 terminals between BT Labs in Martlesham and CNET in Lannion through an ATM Virtual Circuit. AAL1 adaptation is carried out between G.703 2048 kbit/s connection through five cross connects and adaptive clock method is employed. It is concluded that the quality of link and coded pictures is very good. AVC-685 [-] Report on European progress on AALs for Class A and B services (UK) This document reports on the progress within Europe on the development of AALs for Class A and Class B services in the context of support for Audio-visual and Multimedia Services (AMS). ETSI NA5's priorities and preferences are AAL Type 1 for Class A CBR AMS and AAL Type 2 (derived from AAL Type 1) for Class B VBR AMS. The document concludes that the SG15 Experts Group should take account of the ETSI decision to give priority to the development of such AAL Type 1 and Type 2. AVC-686 [-] An AAL for Class B services (BT) This document describes the requirements for an AAL for class B services, that is, ones that have Variable Bit Rate (VBR) and are delay sensitive; and offers a proposal for such AAL2. The proposal is an extension of the existing AAL1 by replacing the SRTS fields with timestamp of about 1 MHz clock and cell rate indication fields to reduce Cell Delay Variation. VBR is assumed to be piecewise constant here. Possible use of FEC and interleaving is also discussed. AVC-687 [94/332] Comments on Draft ITU-T Rec. H.262|ISO/IEC 13818-2 (Rapporteur) AVC-688 [94/331] Comments on Draft ITU-T Rec. H.222.0|ISO/IEC 13818-1 (Rapporteur) These two documents summarize the comments on the Draft Recommendation H.262 | ISO/IEC 13818-2 (DIS text dated 10 May 1994) and H.222.0|ISO/IEC 13818-1 (DIS text dated 10 June 1994) which have been collected from the members of the Experts Group and the ITU-TSB translator for the French text. Two types of comments are listed; those with some possible normative change or clarification and those requiring only editorial change. AVC-689 [-] Reduction of the bit-rate of compressed video while in its coded form (BT Labs) This document presents a technique, operating on the coded data, for further reducing the bit rate of video already compressed with a predictive coding algorithm. Though illustrated with a motion compensated interframe hybrid DPCM/DCT algorithm, it is also generally applicable to other predictive coding schemes, the key elements being the discarding of some coded data, the calculation of the distortion introduced and the later inclusion of correction signals as a normal part of the lower rate data. Low additional delay and no new constraints on the originating coder are noteworthy characteristics of the method. AVC-690 [-] Packet video transport in ATM networks with single-bit feedback (AT&T) This contribution describes simulation results of a rate-based feedback mechanism for congestion control with real-time ABR (Available Bit Rate) video traffic. The results show that the rate-based mechanism is very useful for the transport of ABR video streams. It is shown that the visual quality of the video sequences degrades gracefully when network congestion occurs, due either to increases in the bandwidth requirements of existing video streams or because of new video streams switching on. It is also shown that efficient use of network resources such as buffers and link capacities can be achieved with a rate-based traffic management scheme. AVC-691 [94/348] Clarification of descriptor usage (Japan) This document proposes an additional table with associated notes for ITU-T Rec. H.222.0 | ISO/IEC DIS 13818-1 to clarify the usage of descriptors. Each descriptor is marked against program in TS/PS, Elementary Stream in TS/PS and CA, AVC-692 [-] Proposal for ITU-T_stream_descriptors (Japan) This document proposes ITU-T specific descriptors for inclusion in H.222.1; descriptor tag values, ITU-T video stream descriptor, ITU-T audio stream descriptor, and ITU-T control stream descriptor. AVC-693 [94/346] Request for ITU-T specific stream_id in MPEG2 System (Japan) This document confirms the Grimstad outcome that a stream_id is required for "ITU-T auxiliary" at least to accommodate video frame synchronous C&I signals. This is independent of possible integration of ITU-T C&I (video frame asynchronous) and DSM-CC. AVC-694 [94/347] Integration of video frame synchronous C&I in DSM-CC (Japan) This document discusses the possibility to integrate video frame asynchronous C&I signals (e.g. for negotiating a common mode of operation at the start of the communication) and DSM-CC protocol in terms of standardization schedule (8 months different), flexibility in the choice of transport layer protocol and transmission efficiency. AVC-695 [-] Consideration of H.222.0 Transport Stream as multimedia multiplexing for audiovisual communications (Japan) This document describes a case study when H.222.0 Transport Stream is used as a possible multimedia multiplexing method for high quality videoconferencing service, presenting coding of TS packets and PES packets. It is reported that transmission efficiency of 94 % and packetization delay of 10 ms have been obtained. Several discussion points have also been raised; AVC-696 [-] An example of call setup procedure in an H.32Z terminal (Japan) This document presents an example of call setup procedures between a LAN audiovisual communication terminal and an ISDN H.320 terminal, where the combination of the LAN terminal and the gateway works as if an H.320 terminal. AVC-697 [-] A study on use of multiple VCs (Japan) This document discusses multiple VC configuration for audiovisual communication with respect to network resource reduction and system flexibility. It is concluded that the multiple VC is not effective in resource saving except for some particular cases, but is advantageous in the flexibility. Use of a separate VC for the system control, DSM-CC and T.120 data is suggested. AVC-698 [-] Mandatory H.320 interworking modes of operation for H.32X (Japan) This document proposes reconsideration of the Grimstad outcome "A minimum set of interworking modes of operation which H.32X terminals should support includes 2B, H0, H11 and H.12" by discussing that the receiving only type of the H.32X terminal is not required of this compatibility and that there are differing views for the symmetrical type of H.32X for conversational services. AVC-699 [-] Protocol model for H.32X terminal (Japan) This document firs discusses the three alternatives for the channel which carries the control information; multiplex in the H.222.0 stream, separate VC, use of user-network signalling. Then it proposes; 1) to construct a control protocol based in the bi-directional channel to cover both symmetrical and asymmetrical audiovisual communications, 2) protocol layering consisting of AAL5, X.224, T.125 (MCS) if relevant, application (common and service specific), 3) use of ASN.1 for representation of the control protocol. AVC-700 [-] Consideration on the optional use of AAL error correcting function at H.32X decoder (Japan) This document discusses three levels of support for the forward error correction; 1) mandatory at both the encoder and the decoder, 2) mandatory at the encoder but optional at the decoder, 3) optional at both the encoder and the decoder. The second alternative is suggested. It also compares three FEC methods in implementation and cell loss impact; 1) diagonal interleaving (I.363 short interleaver), 2) orthogonal interleaving (I.363 long interleaver), 3) parallel writing and reading (AVC-617). The third method is suggested for the above decoder option solution. AVC-701 [-] Specification of H.32X hardware for the interconnection experiment (Japan) This document proposes mandatory and optional specifications for the H.32X hardware interconnection trials. Participation is solicited for not only bi-directional equipment but also transmit or receive only terminals, servers, test signal generators. AVC-702 [-] Terminal to terminal signalling in H.32X (Siemens) This document recommends to provide a unified description of H.32X signalling procedures covering both end-to-network and end-to-end signalling, and to consider use of acknowledgment procedures for sub channel establishment and release in H.222.1. Appropriate H.222.0 syntax for "request establishment", "confirm establishment" and "confirm release" need be investigated. It is also pointed out that AAL parameters can be included in the Q.2931 SETUP message. AVC-703 [-] Multiplexing protocols for H.222.1 (Siemens) After comparing Program Stream and Transport Stream in functions, multiplexing capacity, protocol structure and implementation, and also reviewing the relationship between TS and ATM/AAL, this document proposes that the H.32X terminal should always be able to decode the Program Stream and that the TS should not be mandatory in a H.32X send terminal. AVC-704 [-] Correspondence with Rapporteurs of SG13 and SG11 (Rapporteur) This document includes five correspondences to Rapporteurs of SG13 and SG11, which have been generated according to the discussion at the Grimstad meeting: 1) priority and error indication primitive parameters at ALL-SAP, 2) network performance assumptions, 3) audiovisual services between the two terminals accommodated in B-ISDN and N-ISDN, 4) AAL1 short interleaver, circuit transport and support of SDT, 5) negotiation and signalling of an operational mode of multimedia multiplex and synchronization. AVC-705 [-] Use of AAL 5 for Carrying CBR MPEG-2 TS for video-on-demand applications (AT&T, Bellcore, IBM, MCI) This document proposes that AAL5 be used as the AAL to transport MPEG-2 TS in CBR video-on-demand applications and provides a rationale for this choice. AVC-706 [-] ATM Forum Audiovisual and Multimedia Services (IBM) This document gives an overview of the SA&A activities covering SA&A framework, AMS system structure, summary of the September meeting highlighting CBR VOD systems, and the next meeting. Temporary Documents Number Source Title TD-1 Rapporteur Agenda for the sole sessions TD-2 Rapporteur Available documents for the Singapore meeting TD-3 Rapporteur H.32X network adaptation protocol reference model TD-4 John Morris Report of ad hoc group on Systems-related Video issues TD-5 John Morris DIS modification to accommodate Systems-related Video issues TD-6 M. Nilsson, J. Rosengren Proposal for a Real-Time Interface Specifications TD-7 Rapporteur Draft summary of the Tuesday discussion TD-8 Rapporteur Comparison of the protocol configuration for audiovisual communication terminals TD-9 (rev) R. ter Horst Report of the discussion on AAL issues TD-10 (rev) S. Dunstan Group discussion on H.32X call phase and H.222.1 signalling TD-11 Rapporteur Draft summary of the Thursday discussion TD-12 C-C. Li H.32X terminal capability structure TD-13 C-C. Li Harmonization with DSM-CC TD-14 Rapporteur Chronicle of H.32Z discussion TD-15 WG B of WP1/9 Draft ITU-T Recommendation - Transport of MPEG2 constant bit rate television signals in B-ISDN TD-16 Rapporteur Draft report of the sole sessions in Singapore TD-17 ITU-T EG Specification for RTI TD-18 ITU-T EG Harmonization of ITU-T C&I and DSM-CC Annex 1 to AVC-743R Documents for the Kamifukuoka meeting (24-27 January 1995) Normal Documents AVC number Pur-pose Title (Source) AVC-708R R Report of the seventeenth Experts Group meeting in Singapore(1-11 November 1994) - Part I and Part II (Rapporteur) AVC-708R R Report of the seventeenth Experts Group meeting in Singapore(1-11 November 1994) - Part III (Rapporteur) AVC-709 R Response to Draft ITU-T Rec. H.222.0 | ISO/IEC 13818-comments (S. Dunstan) AVC-710 P Draft H.24X (M. Nilsson) AVC-711 R SG13 Report and Liaison Statement on AAL Matters (SG13 Rapporteurs for Q.6/13) AVC-712 R Liaison Statement on ATM Network Performance ( SG13 Rapporteurs for Q.16/13) AVC-713 R List of open issues towards the Kamifukuoka meeting (Rapporteur) AVC-714 D LAN video standardization (AT&T) AVC-715 P Draft H.222.1 (Editor, Stuart Dunstan) AVC-716 P Draft H.32X (Editor, Chia-Chang Li) AVC-717 P Draft H.32Y (Editor, Hayder Radha) AVC-718 P Draft H.32Z (Editor, Geoff Morrison) AVC-719 P Usage of ITU-T stream_id (Japan) AVC-720 P Usage of program and program element descriptors (Japan) AVC-721 P Protocol Stack for H.24X Negotiation Channel (Japan) AVC-722 P Amendment to Capability Description in H.24X (Japan) AVC-723 D Representation of transfer rate in broadband audiovisual communications (Japan) AVC-724 D H.24X channel (Japan) AVC-725 D C&I signals and their channels (Japan) AVC-726 D Identification of H.32X, H.32Y and H.320 at the start of the call (Japan) AVC-727 I Hardware Experiment on Bit Errors (Japan) AVC-728 D Use of AAL5 for adapting narrow-band audiovisual terminals to broad-band ISDN environments (Japan) AVC-729 D Comments on H.32Z (Japan) AVC-730 P DSM-CC over ATM architectures and session descriptions (BNR) AVC-731 D DSM-CC over ATM profiles for hybrid ATM/MPEG and full ATM architectures (BNR) AVC-732 P Pretransmission of high priority information (AT&T) AVC-733 P On the need for including frame numbers in transport stream packets (AT&T) AVC-734 P Only P-frame coding for multipoint video (AT&T) AVC-735 I&P Feedback of received jitter for RTD model (AT&T) AVC-736 D Comments on the decision of H.222.1 TS PDU (KAIST) AVC-737 P Q.2931 Signaling Enhancements to support Video-on-Demand (IBM) AVC-738 I ATM Forum AMS Status (IBM) AVC-739 P Proposal for H.222.1 acknowledged signalling procedures (Siemens) AVC-740 P Use of new H.222.1 stream id (Siemens) AVC-741 P An AAL for variable bit rate services (KPN, BT) AVC-742 I&P H.222.1 issues (BT) Abstract AVC-707R Report of the seventeenth Experts Group meeting in Singapore (1-11 November 1994) - Part I and Part II (Rapporteur) This document records the outcome of the Singapore sole sessions held in November 1994, summarizing the discussion and identifying action items. AVC-708R Report of the seventeenth Experts Group meeting in Singapore (1-11 November 1994) - Part III (Rapporteur) This document records the outcome of the Singapore joint sessions held in November 1994, covering Requirements, Video, Systems and DSM sub-groups AVC-709 Response to Draft ITU-T Rec. H.222.0 | ISO/IEC 13818-comments (S. Dunstan) This document reports the response of the Singapore meeting to ITU-T comments on Draft International Standard ISO/IEC 13818-1: Systems in AVC-688. It also lists a number of editorial errors in IS which should be addressed. AVC-710 Draft H.24X (M. Nilsson) This document is a draft for the definition of terminal capabilities and their exchange procedures at the start of or during communication. The capabilities are represented in ASN.1 notation. AVC-711 SG13 Report and Liaison Statement on AAL Matters (SG13 Rapporteurs for Q.6/13) This document contains the outcome of the SG13 meeting in November 1994 on the AAL1/2 matters. It also includes a liaison response to SG15 and our original questions. AVC-712 Liaison Statement on ATM Network Performance ( SG13 Rapporteurs for Q.16/13) This document provides the SG13 comments on the network performance scenario as contained in AVC-635; the assumption is reasonable for CLR, pessimistic for BER and end-to-end delay, optimistic for CDV which is noted to be strongly dependent on bit rate. There are also included several questions regarding required performance for video services. AVC-713 List of open issues towards the Kamifukuoka meeting (Rapporteur) This document lists open issues which were identified after the Singapore meeting. They are classified into categories of H.222.0, H.262, "network adaptation", C&I and DSM-CC and Draft Recommendations H.222.1, H.32X, H.32Y, H.32Z, H.24X. AVC-714 LAN video standardization (AT&T) This document discusses the importance of incorporating non-guaranteed bandwidth LANs into H.32Z from interoperability point of view, or ITU-Ts role. It also addresses some technical issues with a stress on end-to-end delay. After listing two directions (to standardize the gateway interface and to standardize the gateway processing as well), this document suggests that the H.32Z effort be split into two parts; H.32Z.1 to focus on GBW LANs, and H.32Z.2 to focus on NGBW LANs, an associated H.22Z and H.24Z (it is noted that this might well be the same as H.24X, which will be used for ATM and PSTN). AVC-715 Draft H.222.1 (Editor, Stuart Dunstan) AVC-716 Draft H.32X (Editor, Chia-Chang Li) AVC-717 Draft H.32Y (Editor, Hayder Radha) AVC-718 Draft H.32Z (Editor, Geoff Morrison) These documents contain updated drafts which reflect discussion at the Singapore meeting and subsequent correspondence. Many open issues are indicated in form of editor's comments. AVC-719 Usage of ITU-T stream_id (Japan) This document lists two possible methods to use the four stream_ids allocated to the ITU-T applications; 1) to make one-to-one correspondence between each stream_id of Type A - D and media, 2) to make the correspondence dynamic. It compares the two methods with respect to demultiplexing, maximum number of streams to be dealt with, and media identification at the PES level. As a conclusion, the first method is proposed as exemplified in the Annex where the first 4 bits are allocated for coding algorithm identifiers and the following 4 bits are allocated for stream numbers. Usage of Type E is proposed to be reserved without clear applications at the moment. AVC-720 Usage of program and program element descriptors (Japan) This document proposes H.222.1 specifications on the decoder interpretation of program and program element descriptors for the receiver and a recommended coding method for the transmitter to guarantee interoperability among audiovisual terminals. The recommended coding syntax forms a subset of the decodable set of syntax. AVC-721 Protocol Stack for H.24X Negotiation Channel (Japan) This document discusses three protocol stacks for the error free transport of H.24X signalling in terms of characteristics required for the H.24X signalling and functions provided by the protocol stack. It suggests to choose X.224 class 0 on top of SSCF + SSCOP and AAL5, and proposes to seek advice of SG8 in the interest of harmonization with the T.120-series protocol stacks. AVC-722 Amendment to Capability Description in H.24X (Japan) This document proposes to improve the ASN.1 representation of the draft H.24X specifications (AVC-710) in three ways; 1) addition of top level definition , 2) use of tagging for OPTIONAL and CHOICE type elements, 3) use of BIT STRING type instead of BOOLEAN for capability indication. AVC-723 Representation of transfer rate in broadband audiovisual communications (Japan) This document discusses transfer related issues such as; 1) relationship between the value declared against the network and the value at AAL-SAP, 2) transfer rate value determined by the end-to-end negotiation and its relevance to AAL parameters in Q.2931, 3) representation of bit rate values for transfer rate capability. As a conclusion, it is suggested to represent the transfer rate capability and the operational rate in 16 bit integer as the multiplier of 64 kbit/s. AVC-724 H.24X channel (Japan) This document compares two solutions to provide a channel for H.24X negotiation signals; 1) single solution where a VC is initially used for only H.24X signalling and subsequently expanded to accommodate audiovisual signals as well, 2) dedicated VC solution where a separate VC is used for H.24X signalling other than a VC for audiovisual signals. Since the negotiation includes choice of AAL, H.222.1 multiplex and bit rate, the dedicated VC solution is supported because of its simplicity and flexibility. AVC-725 C&I signals and their channels (Japan) This document lists five different type of C&I signals for broadband audiovisual communication terminals; 0) video frame synchronous control signals, 1) video frame asynchronous H.24X capability information, 2) video frame asynchronous control and indication signals like H.230 ones, 3) video frame asynchronous DSM-CC signals, 4) video frame asynchronous mode change signals. Then it discusses appropriate channels for each category and in what Recommendation each category be specified. AVC-726 Identification of H.32X, H.32Y and H.320 at the start of the call (Japan) This document analyzes interworking among H.32X, H.32Y and H.320 terminals at the call setup phase of communication, pointing out that a potential problem is in H.32X placing a call in the broadband proper mode of operation. It provides three possible solutions; 1) inclusion of two or more operational modes in the setup message, 2) redialing if no response is obtained, 3) use of a priori knowledge. AVC-727 Hardware Experiment on Bit Errors (Japan) This document reports experimental results on visual impact of bit error on decoded pictures using an H.261 base HDTV codec. Error rates of 10-3 - 10-8 have been tested, switching on/off RS(112,108) error correction. It concludes that the results support the argument of AVC-657 that bit error correction is necessary even for the best case network performance scenario in AVC-635. Processed pictures are demonstrated. AVC-728 Use of AAL5 for adapting narrow-band audiovisual terminals to broad-band ISDN environments (Japan) This document discusses H.320 adaptation to the ATM environments by using AAL5, where the received clock from the N-ISDN is used for transmitting the CBR signal in case of interworking, while an independent clock is used in case of communicating with another ATM terminal. It raises that the Experts Group should urgently consider such terminal configuration and gateway functions. AVC-729 Comments on H.32Z (Japan) This document discusses the issue of guaranteed bandwidth vs. non-guaranteed bandwidth LANs for generating Recommendation H.32Z. It suggests for H.32Z to require that ' H.32Z terminal + Gateway ' work as a 'virtual' H.320 terminal, not to specify whether LAN is guaranteed bandwidth and to describe the H.32Z terminal configuration and protocol for Iso-Ethernet as an example. AVC-730 DSM-CC over ATM architectures and session descriptions (BNR) This document identifies three potential architectures for operating MPEG DSM-CC over the ATM network; 1) hybrid ATM and MPEG switching of MPEG TS, 2) full ATM switching of MPEG TS with segregated Session Signaling, 3) full ATM switching of MPEG TS with integrated Session Signaling. It proposes that the three architectures and the two session implementation descriptions be included in the meeting report for future reference. AVC-731 DSM-CC over ATM profiles for hybrid ATM/MPEG and full ATM architectures (BNR) This document identifies standards profiles for the three MPEG DSM-CC over ATM architectures; Hybrid ATM/MPEG, Full ATM with segregated Session Signaling and Full ATM integrated Session Signaling. It discusses interpretations of H.32X, H.24X and H.222.1 for different DSM-CC over ATM architectures and urges SG15 to establish a work for harmonizing H.32X, H.24X and H.222.1 with DSM-CC for customer premise equipment compatibility and efficiency. AVC-732 Pretransmission of high priority information (AT&T) This document discusses the use of data partitioning in the network environments where different priorities are not supported, proposing that in such cases the HP information can be pre-transmitted using a reliable transport protocol and stored in the decoder's memory to be used during the real-time decoding when cell losses occur. It lists several functionalities and corresponding syntax to achieve them. AVC-733 On the need for including frame numbers in transport stream packets (AT&T) This document proposes to include frame_sequence_counter in the Transport Stream adaptation field to facilitate the decoder recovering from moderately large packet losses , which may occur on conventional networks. AVC-734 Only P-frame coding for multipoint video (AT&T) This document proposes inclusion of a sequence level indicator for P-only coding to allow merging of multiple video streams with simple header manipulations so that the merged stream can be decoded by a regular decoder. AVC-735 Feedback of received jitter for RTD model (AT&T) This document proposes to optionally send information about the CDV, as estimated at the decoder, back to the encoder; which consists of three pieces of information an estimate of the received jitter, the available physical buffer size (once), and information about frames skipped due to decoder buffer underflow. Then the encoder can optionally adjust its coding to accommodate the CDV. This alleviates the need for the decoder to be designed with enough buffering to prevent overflow and underflow given the maximum possible jitter, it also minimizes the delay. AVC-736 Comments on the decision of H.222.1 TS PDU (KAIST) This document discusses overlapping fields of the MPEG-2 TS packet header and the ATM cell header towards obtaining high transmission efficiency. It indicates a possible structure of H.222.1 TS PDU where sync-byte and PID are removed to accommodate H.222.1 specific functions. AVC-737 Q.2931 Signaling Enhancements to support Video-on-Demand (IBM) This document proposes that the VOD application information be exchanged during call setup using B_LLI information element, that the H.222.1 information be coded in layer 2 protocol field in octet 6, and that the next two octets (6a and 6b) contain profile and selection request correlation ID. It also proposes that this request be forwarded to SG11 through SG15. AVC-738 ATM Forum AMS Status (IBM) This document reports the outcome of the ATM Forum AMS group meeting in December 1994, highlighting the agreement to adopt the 1-N PCR aware AAL5 packing and a baselevel of N = 2 (5/8 cell PDUs) as the default PDU size to be supported. Larger MTU size (>2) can be negotiated via signaling for SVC or network provisioning by PVCs. AVC-739 Proposal for H.222.1 acknowledged signalling procedures (Siemens) This document presents details of the terminal to terminal signalling using acknowledgment procedures for the set up and release of H.222.1 subchannels where PDUs are coded using PSM and PSI tables in the Program Stream and Transport Stream respectively and a descriptor identifies the meaning of the tables. Proposed text for H.222.1 is contained in Annex to this document including SDL diagrams. AVC-740 Use of new H.222.1 stream id (Siemens) This document proposes that only one of the ITU-T Rec. H.222.1 type A-E stream_ids is required, with the first byte of the PES packet payload (labeled as stream_id_extension) being a multiplexing field. It further proposes that the complete codespace in the stream_id_extension field be freely assignable. AVC-741 An AAL for variable bit rate services (KPN, BT) The document provides ETSI NA5 SAM's current progress on an AAL definition for variable bit rate services to assist SG15 in its development of an AAL for variable bit rate services. It states three VBR service specific functions; 1) detection and recovery of lost or misinserted cells, 2) either correction of CDV introduced by the network or passing of CDV information to the next higher (application) layer, 3) bit rate recovery, and then lists two alternative positions for those functions; 1) AAL2 to be defined, 2) H.222.1 layer on top of AAL1 SAR with null CS or AAL5 SAR and CPCS with null SSCS. AVC-742 H.222.1 issues (BT) This document addresses bit error correction and timing recovery functionality in the network adaptation, proposing the following FEC block structure providing Reed Solomon FEC and jitter removal and timebase recovery functionality in the H.222.1 layer. +-------------------------------------------------------------------+ | RS | | | | | MPEG | RS | | Sync | Flags | | | < BitRate > | PS/TS | FEC | +-------------------------------------------------------------------+ |<---1 byte--->|<-1 byte->|<--2 bytes-->|<--2 bytes-->| |<-4->| |<---------------------------255 bytes----------------------------->| Temporary Documents TD-1 Rapporteur Agenda for the Kamifukuoka meeting TD-2 Rapporteur Available documents for the Kamifukuoka meeting TD-3 Rapporteur Work plan after February 1995 TD-4 S. Okubo Observations regarding Draft Recommendations TD-5 ITU-T|ISO/IEC Defect report procedure TD-6 S. Dunstan Possible use of stream ids in H.222.1 TD-7 LBC Group Draft Recommendation H.24P - Version 3A TD-8 K. Yamazaki Origin of CDV TD-9 D. Skran PCWG press release TD-10 S. Dunstan Report on network adaptation and Draft Rec. H.222.1, 24-25 January 1995 TD-11 V. Balabanian Terminal information exchange during call set-up TD-12 Secretariat List of participants TD-13 S. Dunstan Draft of H.222.1 following the Kamifukuoka meeting TD-14 Editorial Group on Draft H.24X Actions to revise AVC-710 TD-15 C-C. Li Draft Recommendation H.32X TD-16 H. Radha Draft Recommendation H.32Y TD-17 G. Morrison Draft Recommendation H.32Z.1 TD-18 S. Dunstan Update of H.32X network adaptation protocol reference model TD-19 K. Hibi Consideration on H.24X protocol stack TD-20 K. Hibi Draft correspondence to SG8 on multiple VCs and error free transport for H.24X TD-21 H. Radha Response to a previous Liaison and request for comments TD-22 L. terHorst Network adaptation and profiling for the broadband audiovisual communication systems and terminals TD-23 Rapporteur Draft meeting report Annex 1 to AVC-800R Documents for the Haninge meeting (15-18 May 1995) Normal Documents AVC number Pur-pose Title (Source) AVC-743R R Report of the eighteenth Experts Group meeting in Kamifukuoka (24-27 January 1995) (Rapporteur) AVC-744 P Draft H.222.1 (Editor, Stuart Dunstan) AVC-745 P Draft H.245 (Editor, Mike Nilsson) AVC-746 P Draft H.310 (Editor, Hayder Radha) AVC-747 P Draft H.321 (Editor, Hayder Radha) AVC-748 P Draft H.322 (Editor, Geoff Morrison) AVC-749 R Seventh progress report of the Experts Group for Video Coding ad Systems in ATM and Other Network environments (Rapporteur) AVC-750 R Report of the Study Group 15 meeting held during 6-17 February 1995 (Rapporteur) AVC-751 P Harmonization of H.245/H.246 (M. Nilsson) AVC-752 A Open issues toward the Stockholm meeting (Rapporteur) AVC-753 A Liaison regarding need for FEC in H.222.1 (SA&A/The ATM Forum) AVC-754 A Liaison regarding DSM-CC (SA&A/The ATM Forum) AVC-755 R MPEG DSM-CC Meeting at Lausanne, Switzerland, March 20-24, 1995 (C-C. Li) AVC-756 R The MPEG Systems committee met in Lausanne, Switzerland on March 20-24 (B. Haskell) AVC-757 P Draft H.22Z (Editor, D. Skran) AVC-758 P Draft H.323 (Editor, G. Thom) AVC-759 P Draft Amendment 1 to ISO/IEC 13818-1 (MPEG Systems) AVC-760 P Draft Amendment 2 to ISO/IEC 13818-1 (MPEG systems) AVC-761 P Draft Amendment 1 to ISO/IEC 13818-2 (MPEG Video) AVC-762 P Proposed corrigendum for ISO/IEC 13818-2 (MPEG Video) AVC-763 P Real-Time Interface specification for Low Jitter Applications (MPEG Systems) AVC-764 P Proposed Addition to H.245 for Jitter Control (in ATM Networks) (AT&T) AVC-765 I Binary primitive polynomial and generator polynomial of Reed-Solomon code (Japan) AVC-766 I Information on the TS packet jitter accompanied by the FEC framing (Japan) AVC-767 P Logical channel set-up procedure (Japan) AVC-768 D Transfer rate for H.310 terminals (Japan) AVC-769 D&P A case study for H.310 communication procedures (Japan) AVC-770 D Terminal specification for H.310 terminals (Japan) AVC-771 P&D Protocol data unit in H.222.1 layer (Japan) AVC-772 P Comments on H.310, H,321, H.245, and H.322 (AT&T) AVC-773 P Proposal to remove FEC from H.222.1 (AT&T, CableLabs, COMSAT, IBM, Telesis, Technologies Laboratory) AVC-774 I&P Concealment of Bit Errors in MPEG2 Video Decoder (AT&T) AVC-775 I&P Proposals for Error Resilience (AT&T) AVC-776 I&P Proposals for Multipoint Video (AT&T) AVC-777 I&P Real-Time Interface Specification for Normal Jitter (AT&T) AVC-778 D&I Descriptor Information to Aid Timing Recovery (AT&T) AVC-779 A Liaison regarding DSM-CC #2 (SA&A/The ATM Forum) AVC-780 A Liaison regarding B-HLI (SA&A/The ATM Forum) AVC-781 P Update of ATM performance assumptions (Experts Group) AVC-782 I Liaison regarding H.320 over AAL and AMS Phase 1 Work Scope (SA&A/The ATM Forum) AVC-783 I A Summary of the April 1995 ATM Forum AMS Meeting (IBM) AVC-784 P An AAL5 only profile for H.32X (IBM) AVC-785 Vacant AVC-786 D&P List of open issues in H.222.1 (Siemens) AVC-787 D&P Explanation of current H.222.1 acknowledged signalling procedures (Siemens) AVC-788 D&P Codepoint and parameter duplication in H.245 and H.222.1 (Siemens) AVC-789 D&P Proposed additions to H.222.1 acknowledged signalling procedures (Siemens) AVC-790 D&P Comments on Draft Rec. H.245 (Siemens) AVC-791 D&P Protocols to support H.245 (Siemens) AVC-792 I H.322/3 and an example software based multimedia conferencing system (Siemens, Monash University) AVC-793 P US National Body Position on MPEG-2 Real-Time Interface (USA) AVC-794 I&D Further clarification on an AAL model for real-time VBR services (BT and KPN) AVC-795 D&P Outstanding H.245 issues for ATM-based systems (BT) AVC-796 D AAL for MPEG-2 Transport Streams (France) AVC-797 D&P Transmission of T.120 information in a LAN environment (TU Berlin) AVC-798 P Proposed Draft Amendment to ISO/IEC 13818-2 "4:2:2 Profile" (MPEG Requirements and Video Subgroups) AVC-799 D Comments on Draft H.323 and H.22Z (Intel) Abstract AVC-743R Report of the eighteenth Experts Group meeting in Kamifukuoka (24-27 January 1995) (Rapporteur) This document records the outcome of the Kamifukuoka meeting held in january 1995, summarizing the discussion and identifying action items. AVC-744 Draft H.222.1 (Editor, Stuart Dunstan) AVC-745 Draft H.245 (Editor, Mike Nilsson) AVC-746 Draft H.310 (Editor, Hayder Radha) AVC-747 Draft H.321 (Editor, Hayder Radha) AVC-748 Draft H.322 (Editor, Geoff Morrison) These documents contain updated drafts which reflect discussion at the Kamifukuoka meeting, SG15 meeting in February and subsequent correspondence. Open issues are indicated in form of editor's comments. AVC-749 Seventh progress report of the Experts Group for Video Coding ad Systems in ATM and Other Network environments (Rapporteur) This document reports major achievements obtained at the three meetings (Grimstad, Singapore, Kamifukuoka) towards defining the following Recommendations of which we are in charge; H.262, H.222.0, H.222.1, H.24X, H.32X, H.32Y, H.32Z.1. It also lists particular items which need consideration of Working Party 1/15. AVC-750 Report of the Study Group 15 meeting held during 6-17 February 1995 (Rapporteur) This document reports the outcome of Working Party 1/15 meeting (7-15 February) and Study Group 15 meeting (6, 16, 17 February), highlighting the issues of our concern; comments on draft Recommendations, new Editors for H.22Z and H.32Z.2, Recommendation numbers, alignment between H.24X and H.24P, cooperation with MPEG, and other liaison statements. AVC-751 Harmonisation of H.245/H.246 (M. Nilsson) This contribution describes some of the differences in Drafts H.245 and H.246 and suggests how they can be harmonised. The following items are discussed; use of ASN.1, lower layer protocols, mode indication, indication of capability, control and indication, messages, document structure. It is concluded that despite their different appearances, H.245 and H.246 are very similar, thus it should be quite easy to remove the minor differences procedures and messages and it would be beneficial to do so, particularly compatibility at the bit level can be achieved. AVC-752 Open issues toward the Stockholm meeting (Rapporteur) This document lists open issues which were identified after the Kamifukuoka meeting. They are classified into categories of "H.222.0", "Video coding and VBR", "Network adaptation", "C&I and DSM-CC", "Draft H.222.1", "Draft H.24X (H.245)", "Draft H.32X (H.310)", "Draft H.32Y (H.321)", "Draft H.32Z.1 (H.322)", "Draft H.32Z.2 (H.323), H.22Z" and "Second phase work" AVC-753 Liaison regarding need for FEC in H.222.1 (SA&A/The ATM Forum) This document requests that the Expert Group should reconsider their decision to include FEC at the H.222.1 layer. Its ground is that since it appears impossible to characterize the error behavior, especially with a single model that is applicable to all transmission systems, the best approach would be to detect for the presence of errors, and then attempt to conceal their effects rather than directly correct the bit errors. AVC-754 Liaison regarding DSM-CC (SA&A/The ATM Forum) This document describes the status of DSM-CC study in the SA&A and lists several work items being considered for the Phase 1 AMS Implementation Agreement or for future work efforts. Interest is shown to the use of DSM-CC U-N messages for the end-to-end session control and management. AVC-755 MPEG DSM-CC Meeting at Lausanne, Switzerland, March 20-24, 1995 (C-C. Li) This document summarizes the outcome of the DSM-CC Subgroup meeting held on March 20-24, 1995, in Lausanne, addressing those items which are either directly related to or may potentially impact the work in ITU-T SG15. The group produced the second Working Draft of ISO/IEC 13818-6 at the end of the meeting. This document covers User-to-Network operations, User-to-User operations, transport of DSM-CC messages, Normal Play Time (NPT) and downloads. AVC-756 The MPEG Systems committee met in Lausanne, Switzerland on March 20-24 (B. Haskell) This document reports the outcome of the MPEG Systems meeting in Lausanne which produced the RTI-LJ specification allowing up to 25 microseconds of jitter (50 us peak-to-peak), regardless of bit rate. It is raised whether the ITU-T should specify a Real Time Interface for "Normal Jitter" (RTI-NJ), perhaps as part of H.222.1, to cater for the ATM environments. AVC-757 Draft H.22Z (Editor, D. Skran) AVC-758 Draft H.323 (Editor, G. Thom) These two documents provide initial drafts for the multimedia multiplex & synchronization and the terminal on non-guaranteed QoS LANS. AVC-759 Draft Amendment 1 to ISO/IEC 13818-1 (MPEG Systems) This document is for amending the procedures to register format_identifier for the private data in H.222.0|ISO/IEC 1388-1 through Registration Authority. AVC-760 Draft Amendment 2 to ISO/IEC 13818-1 (MPEG systems) This document is for amending the procedures to register copyright_identifier for the Systems stream of H.222.0|ISO/IEC 1388-1 through Registration Authority. AVC-761 Draft Amendment 1 to ISO/IEC 13818-2 (MPEG Video) This document is for amending the procedures to register copyright_identifier for the Video stream of H.262|ISO/IEC 1388-2 through Registration Authority. AVC-762 Proposed corrigendum for ISO/IEC 13818-2 (MPEG Video) This document lists several corrections to the final text of H.262|ISO/IEC13818-2: 1) dual-prime vertical vector range, 2) semantics for chromaticity parameters, 3) reservation for signed_level == -2048, 4) first frame after any sequence_header (), 5) frame_pred_frame_dct in progressive frames, 6) VBV, 7) description for profile_and_level_indication, 8) typos, 9) definition of slice_picture_id, 10) semantics for copyright_identifier. AVC-763 Real-Time Interface specification for Low Jitter Applications (MPEG Systems) This document is Committee Draft produced at the Lausanne meeting which specifies t-jitter as 25 microsecond (jitter shall be +/- 25 microsecond or less at the input of an RTI-LJ decoder). AVC-764 Proposed Addition to H.245 for Jitter Control (in ATM Networks) (AT&T) This document proposes additional H.245 messages for transmitting the following information from the decoder; 1) decoder buffer size available for jitter removal, 2) an estimate of the received jitter at the decoder, and 3) indication of frame skipping by the decoder. This is to assist the encoder to control its coded data generation so that the decoder buffer does not underflow nor overflow. AVC-765 Binary primitive polynomial and generator polynomial of Reed-Solomon code (Japan) This document summarizes the binary primitive polynomial and the generator polynomials of RS codes which are used in existing standards or applications. It is suggested that either primitive polynomial of X8+X4+X3+X2+1 or X8+X7+X2+X+1 is appropriate for H.222.1 and the choice of generator polynomial affects hardware complexity. AVC-766 Information on the TS packet jitter accompanied by the FEC framing (Japan) This document analyzes the TS packet jitter due to TS packet mapping on FEC frame and FEC frame mapping on AAL-SDU. The former is one TS packet period time (250 us at 6 Mbit/s) without alignment while the latter is one cell period time (70 us at 6 Mbit/s) without alignment. If the alignment is made between FEC frame with AAL-SDU, efficiency decreases due to padding. AVC-767 Logical channel set-up procedure (Japan) This document first discusses allocation of functions to higher layer modules (H.222.1, H.245 and H.310) to clarify the protocol configuration for logical channel set-up. Then it proposes to use both H.222.1 SE and H.245 procedures, because they are considered to have different functionalities, and application dependent control should be managed by the Call Management (H.310) module. AVC-768 Transfer rate for H.310 terminals (Japan) This document reviews some methods to reproduce multiple rate clocks in a step of 64 kHz in the receiving terminal and concludes that though the current representation of the transfer rate is appropriate, further study is needed for whether any value of n be mandatorily supported by the H.310 terminal. It is also suggested to study the upper bound of the transfer rate (maximum value of n) for each type of the H.310 terminal. AVC-769 A case study for H.310 communication procedures (Japan) This document presents a case study to clarify the whole communication procedures from a call setup to the intended audiovisual communication by listing all the relevant events for an example case of audiovisual communication. It focuses on the mode switching for which two proposals have been made, describing their information flow in the control and audiovisual channels. Various questions and observations are provided and some specific proposals are made with respect to the default mode and mode request. It also points out that the relationship between H.222.1/H.245 messages and DSM-CC messages be clarified. AVC-770 Terminal specification for H.310 terminals (Japan) This document discusses first the basic specifications of high quality audiovisual terminal in ATM environments consisting of AAL5 and TS and then presents available technologies for inter connectivity with H.320 and compares their features, highlighting the configuration based on AAL5 and TS. It suggests to make a proper framework of ITU-T Recommendations for different type of audiovisual terminals in ATM environments, taking into account not only B-ISDN but also ATM LANs. AVC-771 Protocol data unit in H.222.1 layer (Japan) This document investigates the H.222.1 PDU in terms of FEC handling in Recommendations, its usefulness for Piecewise Constant Bit Rate (PCBR) applications, and jitter due to FEC framing. It concludes that; 1) FEC should be optional for H.310 A1, B1, A2, and B2 terminals, 2) the specifications of the H.222.1 PDU for PCBR data should be left as "for further study" until the implementation of the PCBR terminals is clarified, and 3) the length of the FEC frames and the packetization method of TS and PS into FEC frames and AAL PDUs need further discussion. AVC-772 Comments on H.310, H,321, H.245, and H.322 (AT&T) This document lists some comments to the draft texts of the four Recommendations in the title. It points out that clarification is needed for where ATM LANs should be handled (H.322, H.321, H.323). AVC-773 Proposal to remove FEC from H.222.1 (AT&T, CableLabs, COMSAT, IBM, Telesis, Technologies Laboratory) This contribution proposes that the SG 15 Video and Systems Experts Group reconsider their decision to include FEC in the H.222.1 layer. The reasons are; additional hardware, non-support of I.363 for forwarding corrupted data , additional protocol overhead, FEC location being appropriately in physical layers. AVC-774 Concealment of Bit Errors in MPEG2 Video Decoder (AT&T) This documents gives experimental results on the impacts of 10 -7 random errors on reproduced pictures for the two cases; one is to forward bitstream with errors to the decoder, the other is to detect errors with AAL5's CRC, discard the information with errors and inform the decoder as to the location of missing information for concealment. The results show that pretty good pictures can be reproduced with the error detection and concealment strategy. As a conclusion, the document proposes to exclude FEC from AAL5 based H.310 terminals, to include FEC only in AAL1 based H.310 terminals with its optimization for AAL1 and without alignment between FEC framing and ATM cells. AVC-775 Proposals for Error Resilience (AT&T) This document addresses error resilience by use of H.262 Data Partitioning syntax in the environments where no priority is provided. It uses pre-transmission of High Priority information so that the decoder can use it when recovering from the packet/cell loss. The document proposes additional text in H.222.1 to enable the above error resilience method. AVC-776 Proposals for Multipoint Video (AT&T) This document proposes additional specifications in H.222.0 and H.245 which allow for simultaneous multiple video displays by coding every frame as a P frame and use I macroblocks within these streams when needed. This technique enables a decoder or MCU to merge multiples of such streams by simple header manipulations. AVC-777 Real-Time Interface Specification for Normal Jitter (AT&T) This document proposes RTI for Normal jitter, considering ATM and other environments where higher jitter is involved than those for RTI-LJ. The specification for t_jitter is 500 microsecond. AVC-778 Descriptor Information to Aid Timing Recovery (AT&T) This document addresses a method to indicate from the encoder to the decoder which parts of the data stream may be used for recovering the Decoder System Clock. An example of ITU_video_timinig_descriptor () is given for discussion. AVC-779 Liaison regarding DSM-CC #2 (SA&A/The ATM Forum) This document reports that the Implementation Agreement includes among other things: 1) the DSM-CC definition of "session", 2) the support of DSM-CC User-Network session messages for session control mapped over ATM connection control, 3) the definition of an end-to-end ATM parameter -- the "correlation id" -- to identify and associate all the ATM-related connections within a session, 4) the definition of ATM signalling parameters needed to support ATM connections under DSM-CC session control. AVC-780 Liaison regarding B-HLI (SA&A/The ATM Forum) This document states the SA&A consideration for the use of B-HLI for the Correlation ID and asks SG11 whether B-HLI be transported end-to-end. AVC-781 Update of ATM performance assumptions (Experts Group) This document provides an update of the Experts Group assumption for the ATM network performance, which is based on the cocommunication with SG13 and braodband network performance experts since July 1994. AVC-782 Liaison regarding H.320 over AAL and AMS Phase 1 Work Scope (SA&A/The ATM Forum) This document contains two liaison statements addressed to ITU-T SG15; 1) H.320 over AAL5 study initiation by ATM Forum, 2) informational correspondence of AMS Phase 1 Work Scope and Schedule. The second one includes scope and time schedule for Implementation Agreement as well as MPEG2/AAL5 packing efficiency and MPEG2 PCR awareness. AVC-783 A Summary of the April 1995 ATM Forum AMS Meeting (IBM) This document reports the outcome of the April Audiovisual and Multimedia Services (AMS) Activities (Service Aspects and Applications(SAA) SWG) meeting which focused on: 1) reviewing the VOD over ATM Implementation Agreement (IA), 2) agreeing on changes and updates to the VOD IA Baseline text, 3) begin planning for phase 2 work items. Use of DSM-CC for VOD out-of-band service selection/control and user-network signalling parameters are highlighted among other things. AVC-784 An AAL5 only profile for H.32X (IBM) This document proposes that the H.32X Draft Recommendation should specify an AAL5 only profile for Terminal Types A1, A2, B1, and B2 consideraing the large number of workstation and PC AAL5 ATM adapters projected to be in use in the future, AVC-785 Vacant AVC-786 List of open issues in H.222.1 (Siemens) This document lists a number of open issues with respect to or surrounding H.222.1. AVC-787 Explanation of current H.222.1 acknowledged signalling procedures (Siemens) This document gives explanation of the H.222.1 acknowledged procedures in form of illustration and examples. It is proposed that the example procedures be included as an appendix to H.222.1 AVC-788 Codepoint and parameter duplication in H.245 and H.222.1 (Siemens) This document discusses the consequence of overlapped information in different channel and concludes that it may not undesirable. It proposes a rule that H.245 should contain only those parameters which are necessary to completely describe the capabilities of a terminal, such that without this parameter the call could not proceed. Furthermore it proposes to add a descriptor indicating a capability set of the remote terminal to judge the acceptance of the requested logical channel establishment. AVC-789 Proposed additions to H.222.1 acknowledged signalling procedures (Siemens) This document proposes the following additions to the H.222.1 acknowledged signalling procedures contained in Annex A of Draft Rec. H.222.1: END PDU and RELEASE indication signal parameter to indicate source of release N(CAUSE) values in the BGREJ PDU indicating reason for logical channel establishment refusal a signal indicating clock synchronisation of the system clock in the remote terminal M-ERROR indication signal and ERRCODE values H.222.1 user plane error codes PDU coding in the Transport Stream. Two phases of signalling are required. N(REQUEST) parameter for the STATREQ PDU to determine format of information to be returned Keep alive function in the ESTABLISHED state AVC-790 Comments on Draft Rec. H.245 (Siemens) This document provides technical comments and editorial comments to the draft H.245. The former address 1) alternative wording for "connection/connectionless", 2) arrangement of acknowledgment messages, 3) relationship between logical channel number and PID/stream_id. AVC-791 Protocols to support H.245 (Siemens) This document raises a question to the statement in Annexes 3 and 4 to AVC-743R that "the SSCOP is tightly coupled to AAL type 5 and therefore unsuitable for use in MPEG Systems" and shows a possible way of using SSCOP PDU in the H.222.1 multiplex. AVC-792 H.322/3 and an example software based multimedia conferencing system (siemens, Monash University) This document describes an example LAN based multimedia conferencing system, with interworking to standard H.320 terminals in the public network via an ISDN gateway. All video and audio codec functions are software based. Common PC platforms and audio and video capture cards are used. This document is provided as an illustration as to what is possible in multimedia conferencing using commonly available PC based hardware. AVC-793 US National Body Position on MPEG-2 Real-Time Interface (USA) This document describes the position of US National Body for JTC1/SC29/WG11 that the RTI should be modified to suit a larger range of applications, that the RTI should not contain a specified value for maximum allowed timing jitter in a bitstream's real-time delivery, and that the RTI only should define a framework that helps MPEG users specify their interoperability requirements between equipment such as video servers, delivery networks, storage devices, and decoders. AVC-794 Further clarification on an AAL model for real-time VBR services (BT and KPN) This document reports the current progress on an AAL definition for variable bit rate services which has been made in SAM/ETSI NA5. It gives modeling of AALs according to I.363 which shows that the functions allocated to H.222.1 in the Experts Group liaison should be in the CS. It also shows the effectiveness of the AAL1-model by means of practical examples including the support of CBR MPEG-2 and a model for AAL2 based on AAL1 as well as possible format for the CS-PDU in AAL2. AVC-795 Outstanding H.245 issues for ATM-based systems (BT) This contribution lists the outstanding issues related to H.245 for ATM-base systems, considers issues raised using e-mail and proposes some solutions. Commonality with solutions for PSTN systems is proposed wherever this is possible. The most outstanding issue is to fix where the logical channel acknowledged procedures be defined; in H.222.1 or H.245 or both. AVC-796 AAL for MPEG-2 Transport Streams (France) This document discusses that although AAL type 1 is seen as appropriate for the transport of MPEG-2 signals, the use of AAL type 5 needs further investigations and that before the use of AAL type 5 is considered as a serious candidate, it is necessary to define and describe the selected option for jitter removal in terms of convergence sublayer so that a clear comparison between both AALs can be made. AVC-797 Transmission of T.120 information in a LAN environment (TU Berlin) This document aims at describing ways of distributing T.120 data information in a mixed multicast and point-to-point environment. It proposes a way to make use of LAN (and WAN?) multicast facilities where possible for more efficient information distribution. The protocol XYZ layer which fills the gap between the services and the QoS offered by the LAN and the needs of the MCS is discussed and a solution is proposed which separates it into two parts: 1) a (set of) generic multicast transport protocols that offers reliable, at least single source ordered, and flow-controllable service, and 2) an adaptation layer that provides the additional T.120/H.22Z specific functionality, where necessary this layer may also make use of reliable point-to-point protocols e.g. for peer negotiations and "connection" setup. AVC-798 Proposed Draft Amendment to ISO/IEC 13818-2 "4:2:2 Profile" (MPEG Requirements and Video Subgroups) This document proposes addition of the "4:2:2" profile based on the experiments which had been carried out by the time of MPEG Lausanne meeting. This profile is a 4:2:2 version of the Main Profile and intended for professional use where multiple generations of encoding and decoding are required. AVC-799 Comments on Draft H.323 and H.22Z (Intel) This document provides various comments toward setting appropriate goals for Draft H.323 and H.22Z addressing scope, terminology, speech coders, control channel, call control, capability negotiation, audio/video synchronization, audio quality assurance, network management, inbound call routing, authentication, support of T.120 data, multiplexing audio and video, packetizing video, echo on PSTN voice calls, specification using real world transport protocols. Temporary Documents # Source Title TD-1 Rapporteur Agenda for the Haninge meeting TD-2 Rapporteur Available documents for the Haninge meeting TD-3 Rapporteur FTP site for Draft Recommendations and other documents TD-4 Rapporteur H-series audiovisual communication terminals TD-5 Editor (G. Thom) Overview of H.323 TD-6 DAVIC Press release TD-7 B. Haskell Various rates in the encoder TD-8 ATM Forum Audiovisual multimedia services: Implementation Agreement 1.0 TD-9 R. ter Horst Report on network adaptation issues (AAL, FEC, CDV compensation) TD-10 Y. Nakaya Possible implementations of FEC and system clock recovery TD-11 Editor (G. Thom) H.323 report TD-12 Editor (D. Skran) H.22Z report TD-13 SG8 (Q.10/8) Harmonizing T.120 and H.24X protocol stacks for ATM TD-14 Telenor, BT, GPT, CSELT Audio level setting in H.320 revision TD-15 J. Ott Issues to be considered for H.22Z and H.323 TD-16 T. Tanaka FEC performance in AAL type 1 TD-17 Rapporteur Draft list of agreements TD-18 B. Haskell Liaison to ISO ISO SC29/WG11 MPEG regarding RTI TD-19 R. ter Horst Liaison to ITU-T SG13/2 Q6 (Mr. Yamazaki) regarding request for FEC without interleaver in AAL type 1 TD-20 B. Haskell Proposed Addition to H.245 for Jitter Control (in ATM Networks) TD-21 B. Haskell Proposed Timing Descriptor TD-22 Editor (S. Dunstan) Resolutions on Draft Rec. H.222.1 and H.245 TD-23 Editor (H. Radha) H.310 Scope for Bi-directional Terminals END Annex 2 to AVC-854R Documents for the Yokosuka meeting (24-27 October 1995) Normal Documents AVC number Pur-pose Title (Source) AVC-800R R Report of the Nineteenth Experts Group meeting in Haninge (15-18 may 1995) (Rapporteur) AVC-801 R H.310 Network Adaptation Protocol Reference Model following Haninge meeting (S. Dunstan) AVC-802 R Open Issues towards the Yokosuka Meeting (Rapporteur) AVC-803 R Report of the Q.6.1 meeting (K. Yamazaki - Rapporteur for Q.6.1/13) AVC-804 R Report of the joint Q.6 meeting (Rapporteurs Q.6 - K.Yamazaki, A.Odedra ) AVC-805 P Liaison requesting the creation of a DSS2 Correlation Identifier Information Element (DSM-CC SWG) AVC-806 R Proposed Liaison Response to ITU-T SG 15 Q.2/15 (B. Petri) AVC-807 R Session and Resource/Correlation identification capability of DSS2 and B-ISUP signalling protocols (SWP2/1 & SWP2/3 of SG11) AVC-808 R Harmonization of T.123 and H.245 protocol stacks for B-ISDN (Rapporteur Q10/8) AVC-809 R MPEG DSM-CC Meeting in Tokyo, July 24-28/95 (Vahe Balabanian) AVC-810 P LAN Addressing Plan In H.323 (E. Doron) AVC-811 P Defining Session ID for H.323 (E. Doron) AVC-812 P H.22z Frame and LAN packet (E. Doron) AVC-813 P Requirements for H.Signalling Recommendation within the scope of H.323 (E. Doron) AVC-814 P Providing Quality of Service on NGQoS LANs/H.323 (E. Doron) AVC-815 P RTP/RTCP use for H.22z (E. Doron) AVC-816 P H.261 Video Payload for H.323 (E. Doron) AVC-817 P H.245 B-LCSE modifications and illustrations (S. Dunstan) AVC-818 P Informative appendix on H.245 procedures (S. Dunstan) AVC-819 P Review of H.245 master slave determination procedures (S. Dunstan) AVC-820 P Non-MCU Multipoint Call Setup (InSoft) AVC-821 P Draft H.310 (Editor, H. Radha) AVC-822 P Draft H.22z (Editor, D. Skran) AVC-823 P Draft H.323 (Editor, G. Thom) AVC-824 R Report of the H.245 Ad Hoc Committee (Chairperson H.245 Ad Hoc Committee) AVC-825 P Conference control in H.323 (Intel) AVC-826 P Comments for H.323 Encryption (Intel) AVC-827 P Gatekeeper and Connection Setup in H.323 (Intel) AVC-828 R Need for H.245 to support addressing and association of media streams carried over separate network connections (Rapporteur Q10/8) AVC-829 P Bi-directional logical channel signalling (BT) AVC-830 P Connection Management Procedures for H.323 (TELES, TUB) AVC-831 D Usability of Today's LAN Multicast Environments for ITU-T Teleconferencing (TUB, TELES) AVC-832 I & D Comments on drafts H.22Z and H.323 (TUB, TELES) AVC-833 I & D The use of Q.931 for H.323 connection setup (TUB/TELES) AVC-834 I & P Proposal for adding a simple ACK/NACK data protocol to H.245 (AT&T) AVC-835 P Syntax for video frame synchronous C&I (Japan) AVC-836 D Comments on bi-directional logical channel signalling in H.245 (Japan) AVC-837 D Considerations on H.310 communication protocol (Japan) AVC-838 I Relationship between DSM-CC and H.245 (Japan) AVC-839 D Common Bitrate for H.310 Terminals (Japan) AVC-840 I Report of H.310 hardware trials (Japan) AVC-841 P Start up procedures for H.310 terminals (Japan) AVC-842 P Gatekeeper, Gateway, and Terminal Procedures for H.323 (PictureTel) AVC-843 P H.245 additions for H.323 (PictureTel) AVC-844 P Comments on the H.323 draft (Intel) AVC-845 P Comments on the H.22z draft (Intel) AVC-846 I DAVIC status report (O. Poncin) AVC-847 D & P Comments on H.321 and H.310 (IBM) AVC-848 I ATM Forum AMS Status (IBM) AVC-849 D ATM Multi-point in H.310 Multi-conference units (IBM) AVC-850 P Comments on H.323/H.310/H.320 related to data protocols (AT&T) AVC-851 P Comments on H.323 (AT&T) AVC-852 D Mapping H.221/H.230 commands to H.245 commands and related issues (D. Skran, H.22Z editor) AVC-854 P Update of H.245 from the LBC Darmstadt meeting Temporary Documents # Source Title TD-1 Rapporteur Agenda for the Yokosuka meeting TD-2 Rapporteur Available documents for the Yokosuka meeting TD-3 Japan A Study of Schemes to Distinguish MPEG-2 Transport Streams among Applications (to ITU-R) TD-4 C. Holborow Text for the RTI compliance testing TD-5 T. Savatier H.262|ISO/IEC 13818-2 IDCT specifications TD-6 S. Okubo Correspondence to SG11 Rapporteur TD-7 ATM Forum Draft Liaison to SG15 TD-8 S. Okubo H.310 discussion items (Part 1) TD-9 W. Lidinsky, F. Burg Overview of work in IEEE 802 on LAN Support of Multimedia Applications TD-10 Vineet Kumar Position of H.323 and H.22z recommendations TD-11 Chairperson H.245 Ad Hoc Committee Report of the H.245 Ad Hoc Committee TD-12 G. Thom H.323/H.22Z discussion items TD-13 G. Thom FIGURE 37/Q.931 TD-14 S. Okubo H.310 discussion items (Part 2) TD-15 ATM Forum Audiovisual Multimedia Services: Video on Demand Specification 1.0 TD-16 T. Savatier et al. Yet another problem in IDCT? TD-17 S. Okubo H.310 discussion results TD-18 D. Skran, G. Morrison Revised text for H.323/H.310 data options TD-19 M. Nilsson FAX to H.245 contributors of the LBC group TD-20 B. Haskell Comments on H.222.1, H.245 TD-21 C. Gates, C. Hansen Reply to TD-19 TD-22 T. Geary Draft Liaison response concerning Delay for QoS and Common routing connections to minimize delay TD-23 M. Nilsson Report of H.245 discussions TD-24 J. Lynch Addition to H.321 re use of SDT in H.321 TD-25 H. Singh Reply to TD-19 TD-26 G. Kajos H.323/H.320 call address and type TD-27 H.323 Working Group H.245 Additions and Changes for H.323 TD-28 G. Thom, D. Skran H.323/H.22Z Session Report TD-29 S. Dunstan Consideration on basic Rec. H.310 terminal communication modes TD-30 K. Hibi Liaison to SG8 on T.120 and H.245 protocol stacks TD-31 G. Morrison Comments on H.310 TD-32 J. Lynch Liaison statement to Q10/8 END Annex 2 to AVC-906R Documents for the Ipswich meeting (16-19 January 1996) Normal Documents AVC number Pur-pose Title (Source) AVC-854R R Report of the Twentieth Experts Group meeting in Yokosuka - 24-27 October 1995 (Rapporteur) AVC-855 D Comments on H.225.0 (RADVision) AVC-856 D Comments to the H.323 Draft (RADVision) AVC-857 R Draft new Questions proposed by WP1/15 (WP1/15) AVC-858 R MPEG Meeting in Dallas, Nov. 6 - 10 / 95 (Hideyuki Ueno) AVC-859 P Changes to Rec. H.222.1 following the Yokosuka meeting (Editor - S. Dunstan) AVC-860 R Quick report of the SG15 meeting in Geneva (Rapporteur) AVC-861 R Liaison to SG15 concerning ATM QoS (SG13) AVC-862 R Report of Rapporteur Meeting, Lannion, France, November 13-17, 1995 (Rapporteur for Question 16/13) AVC-863 withdrawn AVC-864 withdrawn AVC-865 withdrawn AVC-866 P Adaptation of RTP to H.323 (RADVision) AVC-867 R Open issues toward the Ipswich meeting (Rapporteur) AVC-868 P Draft H.310 (Editor - H. Radha) AVC-869 P Draft H.225.0 (Editor - D. Skran) AVC-870 P Draft H.323 (Editor - G. Thom) AVC-871 R Meeting report (Working Party 1/15) AVC-872 P Further considerations regarding the H.310 start up procedures (Japan) AVC-873 D&P Terminal protocol identification by B-HLI (Japan) AVC-874 P Mandatory audio coding for native H.310 mode (Japan) AVC-875 P Semantics of video frame synchronous C&I (Japan) AVC-876 P Common bitrate for H.310 terminals (Japan) AVC-877 P Proposed description of communication protocol in draft Rec. H.310 (Japan) AVC-878 D Comments on draft H.310 (Japan) AVC-879 P H.323, H.225, and H.245 Comments and Assigned Work Items (PictureTel) AVC-880 I Current status of G and H-series Recommendations for audiovisual communication systems (Rapporteur) AVC-881 P Some editorial comments on H.245 (Siemens) AVC-882 P Comments on references to H.245 in H.310 and H.323 (Siemens) AVC-883 P Proposal for amendments to the text of ITU-T Draft Recommendation H.310 (France) AVC-884 P Q.931 Signaling in H.323 (Intel) AVC-885 P Comments for H.323 Registration and Address Translation (Intel) AVC-886 D H.323/H.225.0 Draft Comments and Revisions (Intel) AVC-887 P H.323 Terminal/Gatekeeper Registration (Intel) AVC-888 P Comments for H.323 Error Recovery (Intel) AVC-889 P Comments for H.323 Clarification (Intel) AVC-890 P Changes to H.245 in support of H.323 (Editor - Dale Skran) AVC-891 I Status of RTP (Editor - Dale Skran) AVC-892 P Annex A to H.225.0(RTP/RTCP) (Editor - Dale Skran) AVC-893 P Annex B to H.225.0(RTP profile) (Editor - Dale Skran) AVC-894 P Annex C to H.225.0(H.261 Packetization for RTP) (Editor - Dale Skran) AVC-895 P Proposed Changes in H.323/H.225.0 (Editor - Dale Skran) AVC-896 D Issues Using the Q-series for Supplementary Services in H.323 (Editor - Dale Skran) AVC-897 R Session and Resource / Correlation identification capability of B-ISDN signalling protocols (Rapporteur for Q.15/11) AVC-898 P&D Usage of Q.931 messages in H.225.0 (TUB) AVC-899 D H.310 ROT and SOT terminals (BT) AVC-900 D Comments on H.310 (BT) AVC-901 D&P Modifications to the H.323 AdmissionRequest set of messages (BT) AVC-902 D&P Changing network bandwidth usage within an H.323 conference (BT) AVC-903 D Liaison letter to Rapporteur for ITU-T SG15 Q.2/15 (SA&A/ATMF) AVC-904 P Need for H.245 to support addressing and association of media streams carried over separate network connections (SG8 Q.10/8) AVC-905 R Special report of ITU-T WP1/9 activities (SG15 Liaison Rapporteur to ITU-T SG9) Temporary Documents # Source Title TD-1 Rapporteur Agenda (General) for the Ipswich meeting TD-2 Rapporteur Available documents for the Ipswich meeting TD-3 Rapporteur Agenda for H.310 discussion TD-4 Rapporteur Definition of H.310 terminal type TD-5 Editor - D. Skran Open issues in H.225.0 TD-6 Rapporteur Draft correspondence to SG11 - terminal protocol identification TD-7 J. Toga Error handling TD-8 M. Reid Jitter and skew proposal TD-9 J. Ott Network/user identification TD-10 V. Kumaar H.245 conflicts and parellels TD-11 Editor - S. Okubo H.310 discussion results TD-12 Editor - S. Okubo Disposition of comments in AVC-878 TD-13 Editor - S. Okubo Disposition of comments in AVC-900 TD-14 Idan Adaptation of RTP to H.225.0 audio and video TD-15 J. Ott Usage of T.120 in conjunction with H.323 TD-16 T. Geary Interoperability of H.323 with V.dsvd terminals TD-17 G. Freundlich Comments regarding H.225.0 messages and H.245 messages in H.323 TD-18 M. Reid Call model message flows TD-19 F. Baker, G. Freundlich Additions to network address specification TD-20 J. Toga Multipoint conference TD-21 P. Cordell, V. Kumaar H.323 terminal types for H.245 master slave determination TD-22 Editor - S. Okubo Draft H.310 TD-23 Editor - D. Skran Draft H.225.0 TD-24 Editor - G. Thom Draft H.323 END