ITU-T Telecommunication Standardization Sector	Document AVC-707R
Study Group 15	11 November 1994
Experts Group for Video Coding and Systems
in ATM and Other Network Environments

Source:	RAPPORTEUR (Sakae OKUBO)	
Title:	REPORT OF THE SEVENTEENTH EXPERTS GROUP MEETING IN SINGAPORE (1-11 July 1994) - Part I and Part II	
Purpose:	Report	

-----------------------

Part I	General
Part II	Sole sessions
Part III	Joint sessions (see AVC-708R)

Part I General

The seventeenth meeting of the Experts Group was held in Singapore as follows;

•	ITU-T sole sessions on 1, 3 and 4 November at the kind invitation of Singapore Telecommunications Limited, 
•	Joint sessions with ISO/IEC JTC1/SC29/WG11 (MPEG) during 7-11 November at the kind invitation of Singapore Institute of Standards and Industrial Research (SISIR).

Part II  Sole Sessions

Contents

1. 	Introduction
2. 	Documentation
3. 	Review of the previous meetings
4. 	Completion of the common text Recommendations
5. 	Video coding matters and VBR
6. 	Network adaptation
7. 	H.24X and signalling
8. 	H.222.1
9. 	H.32X
10.	H.32Y
11.	H.32Z
12.	Joint sessions with MPEG
13.	Others

1. General

The ITU-T sole sessions were held at Comcentre on 1, 3 and 4 November 1994 at the kind invitation of Singapore Telecommunications Limited.  At the end of the sessions, Chairman thanked the hosting organization for providing an opportunity to meet in Singapore, excellent meeting facilities and secretarial support.

We had also a closing session on 11 November to review both sole and joint sessions.

It is noted that the discussion session for H.222.1, H.32X, H.32Y, H.32Z and related matters was co-chaired by Rapporteur and each Editor; Mr. Stuart Dunstan, Mr. Chia-Chang Li, Mr. Hayder Radha and Mr. Geoff Morrison.

2. Documentation (TD-2)

For the sole sessions, 34 AVC-numbered documents and 18 temporary documents have been made available as listed in Annex 1.

3. Review of the previous meetings

3.1 Experts Group July meeting in Grimstad (AVC-673R, 674R)

The previous meeting in Grimstad meeting was very briefly reviewed.  Mr. S. Dunstan announced that Table 1 (AAL primitives and their parameters) in Annex 3 to AVC-673R should be corrected as in Annex 1 to AVC-704.  Mr. C-C. Li presented a report on the DSM-CC extension work as in Annex 2 to AVC-674R

3.2 Correspondence to Rapporteurs of SG13 and SG11 (AVC-704)

Rapporteur reported that the correspondence to SG13 and SG11 has been sent out, but the one to SG8 is yet to be drafted.

3.3 List of open issues (AVC-676)

Rapporteur provided a list of open issues which were identified after the Grimstad meeting.

3.4 Fora/Consortia (AVC-706)

Mr. O. Poncin presented a summary of the DAVIC activities, focusing on the area of work and the time schedule.

Mr. J. Lynch presented AVC-706 which summarizes the current status of SA&A in The ATM Forum.

4. Completion of the common text Recommendations

4.1 H.262|ISO/IEC 13818-2 Video (AVC-687; TD-4, 5, 9, 17)

Technical comments with T numbers have been reviewed.

	T3 bit_rate definition
	T4 VBV for VBR

After reviewing TD-4 and TD-5, the meeting concluded that these comments can be superseded by that "we agree to fix the problem based on the Morris proposal (TD-5)".

4.2 H.222.0|ISO/IEC 13818-1 Systems (AVC-688, 691, 693; TD-5, 10)

	4.2.1 Review of the technical comments with T numbers (AVC-688)

	T6, T7 system clock accuracy specification

This should be presented with a clearer rationale at the joint sessions.

	T9 PAT transmission
	T29 PSI transmission

It has been noted that the timing of PSI transmission should be specified in either of H.222.1 or H.24X as part of the call set-up procedures if it is left to the application standard.

T29 needs clarification; assistance of the originator of the comment should be sought.

	T13 R/P problem

This comment can be superseded by that "we agree to fix the problem based on the Morris proposal (TD-5)".

	T17 PTS/DTS confusion

This should be presented at the joint sessions with the last sentence modified as "We strongly suggest, on grounds of interoperability, that a definition consistent with MPEG-1 be used."

	T22, T23, T24, T36 ITU-T auxiliary

See §4.2.3 below.

	T44 RTI

The comment should read "An agreed specification should be included ...."  We support the inclusion of an RTI specification in the current H.222.0, and we suggest 1 ms jitter tolerance based on the average case scenario of the ATM network performance assumption (AVC-635).  See Annex 3 to this report for some more discussion details.  The meeting agreed to send this conclusion to the joint sessions with MPEG as contained in Annex 4 to this report.

	4.2.2 Descriptor usage (AVC-691)

The meeting supports the clarification of the descriptor usage proposed in AVC-691.  Mr. Y. Nakaya stated that the specification in Notes 1 and 2 may have an alternative; either solution is acceptable, it is more important to clarify the specification.

	4.2.3 ITU-T auxiliary (AVC-693; AVC-694)

AVC-693 proposed to confirm the necessity of ITU-T Auxiliary channel.  The following comments and information were given:

•	DSM-CC should support time related signals and C&I signals can be accommodated there.
•	Standardization timing should be counted; H.222.0|ISO/IEC 13818-1 is to be finalized next week.
•	The outcome of the Grimstad meeting should be maintained unless there are strong reasons.
•	The integration of C&I and DSM-CC should target the DSM-CC Extension, not the existing DSM-CC.
•	DSM-CC Extension is focusing on VOD systems.  The time relationship between DSM-CC and audiovisual signal is not so critical, requiring precision in the order of one second.

After having heard them and the outcome of the small group discussion coordinated by Mr. S. Dunstan, the meeting agreed to this proposal in the context of end-to-end signalling which covers video frame synchronous signals, capability exchange signals and mode change signals.  See Annex 2 to this report for more details.

4.3 Ongoing studies (TD-4, 5, 6)

A summary of systems and video buffering issues related to VBR is given in TD-4 and TD-5.  The RTI work was reported to be under discussion at the MPEG ad hoc group.

5. Video coding matters and VBR (AVC-690)

AVC-690 presented simulation results of a rate-based feedback mechanism for congestion control with real-time ABR (Available Bit Rate) video traffic.  D1 tape demonstration will be given at the joint sessions with MPEG.

6. Network adaptation

6.1 Function allocation (TD-3, AVC-678, 679; AVC-699)

TD-3 is an update of the H.32X network adaptation protocol reference model.  It is noted that allocation of each function to an appropriate layer is awaited, particularly "jitter removal" and "error correction" functions.

AVC-678 presented an infrastructure of computer based AMS terminal and its impacts on the jitter removal function allocation, while AVC-679 presented a generic configuration of video distribution with function allocation and signalling requirements.

Through questions and answers, the following were clarified:

•	VOD is a subset of the "video distribution" mentioned in AVC-679.
•	Additional card-to-card jitter is in the order of microseconds to milliseconds depending on load of the system when packets are transferred through the bus or the CPU in the figure of AVC-678.
•	Some of the items listed as "Q.2931 signalling requirements" seem to belong more properly to the end-to-end control (DSM-CC), not end-to-network signalling; e.g. content (movie) and service selection request correlation ID.

More details of the protocol reference model were discussed in a small group coordinated by Mr. S. Dunstan.  Its report, which was approved by the meeting at large, is contained in Annex 2 to this report.

6.2 AAL for CBR

6.2.1 Solution for Video on Demand service (AVC-705; AVC-679; TD-15)

AVC-705 proposed use of AAL5 to carry CBR coded MPEG-2 Transport Streams for VOD applications in the end-to-end ATM environments.  There were some questions and answers regarding the background of this proposal:

•	ATM jitter has been estimated to be less than 2 ms for CBR.  Benefits of VBR statistical multiplex gain may be obtained only by allowing CDV of the order of 10 ms. 
•	It has been found feasible by experiments that PCR can be recovered with 3 ppm accuracy under CDV of 2 ms.
•	Transmission errors are assumed to be maintained sufficiently low at the physical layer, thus error correction is not necessary at the AAL or higher layer.  There was a comment that this assumption is not in line with AVC-635 (ATM network performance assumptions) where bit error may occur once every 2.5 minutes for a 6 Mbit/s channel even in the best case scenario. Furthermore bit error correction was concluded not to match with AAL5 at the Grimstad meeting.
•	The background of the proposal was summarized as pragmatically AAL5 chips being available and it appearing to work.

Mr. Beaumont informed the meeting that SG9 Rapporteur's group recently decided to recommend AAL1 for video distribution services as in TD-15.

Related to the network performance scenario, Mr. Radha pointed out that CDV and end-to-end delay figures are dependent on the cell transmission rate, thus AVC-635 should be modified accordingly.

6.2.2 Generic solution (AVC-685; AVC-704)

Mr. Beaumont presented the ETSI study results on the AALs for Class A and B services, stressing that priority be given to the AAL1 and its extension to AAL2.  The following comments were obtained in the discussion:

•	As to the question that the AAL2 solution of AAL1 embedded functionality loses some functionalities of AAL1, the intention was clarified to facilitate development of the AAL1/2 switchable device. 
•	There was a question whether the 3 bit cell sequence number is sufficient for VBR traffic which AAL2 should support.  There may occur longer bursts for VBR, but they are hard to recover even if their occurrence is known by the sequence numbering.

6.2.3 Error correction (AVC-700)

As a preliminary conclusion, the meeting supported the case 2 (FEC is mandatory at the encoder, but optional at the decoder), requesting further consideration by the next meeting.  A specific way of forward error correction is yet to be selected.

Location of FEC in the protocol stack is yet to be worked out.

6.2.4 Position of the Experts Group for the AAL issue (TD-9)

For further discussion and establishment of the Experts Group position, Mr. ter Horst coordinated a small group discussion and his outcome is contained in Annex 3 to this report.  It addresses applicability of AAL1 and AAL5 in the matrix of the transmission system (End-to-end ATM / Hybrid ATM + circuit emulation) and services (Conversational / Distribution / Interactive video retrieval), allocation of error correction and jitter removal, profiling of the network adaptation, and RTI specifications.  A preliminary set of profiles are provided as a basis for further consideration; "main profile" for symmetrical terminals containing both AAL1 and AAL5, "simple profile" for asymmetrical terminals which contain AAL5 in one configuration and AAL1 in another configuration.  The objective of profiling is to limit the combination to a small number and allow maximum interworking.  This report was approved by the meeting at large.

Contributions are requested for settling the issue at the next meeting.

6.3 AAL for VBR (AVC-686)

AVC-686 provided requirements and a proposal for AAL2 as extension of AAL1.  The meeting welcomed this first input on this topic as a good starting point.  Through the Q&A session, the following comments and clarification were obtained:

•	Availability of the 10**(-11) accuracy of the clock in every ATM switch should be checked.
•	Clarification is needed to what reference point the "piecewise constant" rate applies.  Multiplexing changes the byte delivery schedule.
•	A single buffer in the terminal is a better choice for implementation.
•	SRTS mentioned in the context of common use of the AAL header field
•	AAL1 based AAL2 is sought to facilitate interworking with N-ISDN terminals.

After the discussion, the meeting identified that there are two different approaches for the VBR AAL reflecting the discussion on the CBR AAL:

•	to define a new AAL2 for VBR,
•	to use the existing AAL5.

If we take the first approach, it is recognized that

•	it is possible to develop AAL2 for VBR as a superset of AAL1 for CBR,
•	the progress of AAL2 is deemed to owe largely to the work of this Experts Group as a potential user (see §9.3/AVC-673R) though final responsibility is in SG13,
•	requirements for functionalities and performance should be well defined.

The meeting concluded that the members are encouraged to provide their views on the possible two approaches and improvements of AVC-686 proposal or counter proposals.

6.4 Multiple VCs (AVC-675, 697; AVC-677)

AVC-675 provided an SG8 view to run the T.120 protocol on a separate VC, and AVC-697 analyzed the advantages and disadvantages of the multiple VC use.  The meeting decided to make provisions for both the single VC and separate VC solutions to handle T.120 data.  The choice should be negotiated at the start of the call.

7. H.24X and signalling

7.1 H.24X and its transport (AVC-677, 699; AVC-704; TD-12)

AVC-677 made a proposal, for further consideration, on the audiovisual communication procedures in the packet based transmission environments.  The meeting supported this proposal as H.24X framework, requesting thorough review by the members.

AVC-699 discussed alternatives for the channel which carries the control information, and proposed to construct a control protocol based on the bi-directional channel and a protocol layering model.  These are reflected in the protocol reference model as contained in Annex 2 to this report.

AVC-699 also proposed use of ASN.1 for representation of the control protocol.  The meeting supported this proposal.  Mr. C-C. Li provided a H.32X capability structure using ASN.1 in TD-12.

7.2 Integration of C&I and DSM-CC (AVC-694, 699; AVC-693; TD-13, 18)

The meeting identified the following three different C&I signals for audiovisual communication terminals and their channels:

•	video frame synchronous control signals in the ITU-T auxiliary PES with PTS,
•	video frame asynchronous control signals (capability messages) in the ITU-T auxiliary PES, or other channels in case of asymmetrical communications,
•	mode change control signals in PSI/PSM.

DSM-CC is understood as video frame asynchronous control signals, and may have some commonality with capability messages in functionality.  They may be multiplexed in the same channel, but this needs further study.  Mr. C-C. Li proposed TD-13 as an input to the joint sessions with MPEG and the meeting supported this proposal with a small modification.  The resulting input document is contained in Annex 5 to this report.

Based on this discussion, the meeting decided to have a joint session with the DSM sub-group in addition to Requirements, Video and Systems sub-groups at this meeting.

7.3 Requirements to user-network signalling (AVC-679, 702)

AVC-679 provided VOD service related requirements to signalling and AVC-702 provided those for AAL parameters.  Work should be done to make an extensive list.

8. H.222.1

8.1 ITU-T stream descriptors (AVC-692)

AVC-692 proposed ITU-T specific descriptors for inclusion in H.222.1.  The meeting agreed to create a new section in H.222.1 and finalize the content by refining this proposal.

8.2 Case study for applying TS to videoconferencing (AVC-695)

AVC-695 provided a case study where H.222.0 Transport Stream is used as multimedia multiplexing method for a high quality videoconferencing service.  The meeting responded to the discussion items raised in this document as follows:

1)	Program descriptor	H.24X capability exchange plays the role of this descriptor in H.32X.
	
2)	Data elementary stream descriptor	This should be defined since we are going to prepare for both separate VC and H.222.0 multiplex approaches for the T.120 data (see §6.4 of this report).
	
3)	Synchronization between audiovisual signal and control signal
	The PES with PTS solution (the Grimstad outcome) is maintained.	
4)	Control data protocol	Error free transport service is to be used.  See Annex 2 to this report.
	
5)	Audio coding laws	This was left to the discussion on Draft H.32X.  See §10 of this report.	

8.3 Terminal to terminal signalling (AVC-702; TD-10)

AVC-702 proposed to use acknowledgment procedures for setup and release of H.222.1 subchannels.  The meeting supported this direction and use of the PSI/PSM syntax for the acknowledgment.  Definition of new descriptors is required for this purpose.  The meeting also supported the proposal to describe a unified procedure for call control and inband signalling in Recommendation H.32X.  The discussion outcome on the procedure is found in Annex 2 to this report.  It is noted that the communication starts with the capability exchange through a VC, including the choice of PS or TS, and then the bandwidth of the VC may be expanded or a separate VC may be established.  The choice of the two alternatives needs further study.

The meeting confirmed that H.222.1 should describe the two procedures with and without acknowledgment.

During the discussion, the following issues have been identified awaiting contributions:

•	choice of AAL for the capability exchange at the start of the call; AAL negotiation through the user-to-network signalling may be useful.
•	identification of H.32X and H.32Y (H.320) terminals; an explicit or implicit mechanism is required.

8.4 Draft H.222.1 (AVC-680)

The meeting reviewed the draft H.222.1 updated after the Grimstad meeting.  Mr. Dunstan indicated that the specifications will be aligned with the ISO/IEC 13818-4 Conformance and that §6 "Interaction with AAL" will describe multiple scenarios.

There was some discussion on §10 "Multiple ATM Layer Virtual Channels":

•	T.120 data accommodation in a separate VC should be included.
•	Hierarchical video may use multiple VCs as discussed at the previous meeting (AVC-664).  There are two ways; one is to split a H.222.0 multiplexed stream into separate VCs by H.222.1, the other is to use H.222.1 multiple instances with an external association mechanism.  In both cases, concern was expressed for legality of split and combined streams to the standard, particularly when cell losses are involved in one stream.

Editor (Mr. S. Dunstan) will revise the text reflecting the outcome of this meeting and post it at the reflector by November 27 (Tokyo time) for further consideration of the members towards the January meeting.

9. H.32X

9.1 Interworking with H.320 (AVC-698)

AVC-698 requested reconsideration for the mandatory requirement of H.32X compatibility with H.320.  The meeting agreed to the proposal that viewing only terminals (H.32X Type A1 and B1) need not mandatorily receive H.320 streams.  For the proposal restricting the mandatory modes of operation of the symmetrical terminals (Type A2 and B2) to 1B audio or 2B audiovisual, opposing views were expressed on the ground that customers would expect higher quality for the H.32X terminal and that inclusion of H.320 processing in the more powerful H.32X device would not cause significant hardware burden.  The meeting decided to maintain the Grimstad resolution until justification for the hardware burden is obtained.

9.2 Support of TS and PS (AVC-703)

In  response to the request of contributions on narrowing down TS/PS alternatives, AVC-703 proposed that the PS alternative should not be excluded.  As a typical area of PS use, audiovisual applications in LAN and WS environments were indicated.  The meeting concluded that both TS and PS should be mandatory at the decoder and that either of PS or TS can be used at the encoder in the H.32X terminal.  Dependency of this conclusion on the terminal type is yet to be clarified.

There was a comment on the implementation discussion in AVC-703 (PS is by software and TS by hardware) that it is bitrate dependent.

9.3 Hardware trial specifications (AVC-701)

AVC-701 proposed specifications for the hardware trial planned to be carried out before the SG15 meeting in November 1995.  Mr. Takishima informed the meeting that currently three organizations are building hardware, they try to test both AAL1 and AAL5, and the tests will be through the NTT experimental network.

The meeting agreed to fixing the "mandatory" parts of the specification at this meeting and confirmed that the hardware trials are for verifying core technologies of the projected Recommendations.  The specifications are contained in Annex 6 to this report.

Participation of other members are encouraged as described in AVC-701.

9.4 Draft Recommendation (AVC-681)

The meeting reviewed the draft H.32X updated after the Grimstad meeting, obtaining the following results:

•	H.320 compatibility related elements, such as H.261, should be indicated in Figure 1.
•	"End-to-end signalling" in Figure 1 takes into account video frame synchronous signals and capability exchange messages.
•	Proposals for data capability codepoints are invited before the submission of the next version.
•	SP@ML encoder and MP@H14 codec is to be considered for Video Codec Capability and the terminal type definition.
•	G.728 is to be included in Audio Codec Capability in the context of H.320 compatibility.
•	VBR is to be mentioned in 4.2.3.
•	According to the Systems conformance specifications, such capabilities as scrambling and trick mode should be considered in §4.2.3.1.
•	Transfer rate should be specified with some quantization, for which proposals are invited, otherwise Editor will distribute his strawman proposal.
•	H.24X capability should have no option in the set of terminal capabilities.  It is noted that H.24X and DSM-CC may potentially have common part.
•	H.261 is taken out from Type A1 and Type B1 capabilities according to the agreement in §9.1 of this report.  However, G-series audio is left with consideration that they may have telephone capabilities.
•	"Equipment" in the title and audiovisual I/O description should be removed.  However, some items which relate to interworking, such as audio level setting, should remain.  The text in H.320 may be usable.
•	§6 "Error resilience" is a placeholder for informative text; advice on the content is welcome.

There was a general comment that if optional capabilities are included, then H.32X should indicate whether they are mandatory or optional.  Mr. Ueno raised a question whether H.222.0 capabilities should parameterize number of channels and bit rates to be handled.  This needs clarification.

Related to "error resilience", Mr. B. Haskell informed the meeting that AT&T experiments showed effectiveness of duplicated transmission of important information, such as headers, in a separate VC against cell loss in the TCP/IP environments.

Editor (Mr. C-C. Li) will revise the text reflecting the outcome of this meeting and post it at the reflector by November 27 (Tokyo time) for further consideration of the members towards the January meeting.

10. H.32Y

10.1 Hardware trial (AVC-684)

AVC-684 presented successful experiments of connecting two different H.320 terminals between BT Labs in Martlesham and CNET in Lannion through an ATM Virtual Circuit.

10.2 Draft Recommendation (AVC-682)

The meeting reviewed the draft H.32Y updated after the Grimstad meeting, obtaining the following results:

•	"Definitions" coordination is suggested to take place among Editors.  The idea is to share a common set of definitions and selecting relevant items in each Recommendation.
•	In Figure 1, "R" point should have interface specifications, but the reference point should not be marked with "R".  If a terminal whose configuration looks like (b) in Figure 1 does not conform to the interface specifications, it is classified as configuration (a).
•	Note 6 in Table 1 is deleted due to lack of clarity.
•	Figure 3 should indicate a 2B case which involves two VCs.
•	In the "AAL Subtype identifier" of Table 2, "Video signal transport" should be swapped with "Circuit transport" in Note 4.
•	In the "AAL Error correction method", "short interleaver" should be removed.
•	Q.939 should be referred to, and it should be stated which specifications dominate if discrepancies are found.

The following were found to require confirmation of SG13:

•	whether IWF can invoke "Structured Data" by  observing LLC,
•	whether "partially filled cells" are usable in the circuit transport.

Editor (Mr. H. Radha) will revise the text reflecting the outcome of this meeting and post it at the reflector by November 27 (Tokyo time) for further consideration of the members towards the January meeting.

11. H.32Z

11.1 Call setup procedures (AVC-696)

In response to the request of information, AVC-696 presented an example of call setup procedures between a LAN audiovisual communication terminal and an ISDN H.320 terminal.

Mr. D. Beaumont advised that terminal numbering issues for Iso-Ethernet are being addressed in IEEE802.9b.  The plan regarding E164 address locations on the LAN is to support static address tables within the Access Unit (hub).

11.2 Hardware experiments

Mr. D. Beaumont mentioned that BT now has some Iso-Ethernet equipment and is preparing for hardware experiments.

11.3 Gateway video processing (AVC-689)

AVC-689 presented a technique, operating on the coded data, for further reducing the bit rate of video already compressed with a predictive coding algorithm.  The meeting observed that this technique is applicable to gateways, MCUs etc. where rate conversion is required.

11.4 Draft Recommendation (AVC-663; TD-14)

Mr. Skran expressed his concern that if H.32Z restricts itself to "guaranteed bandwidth" networks, there is a danger that proprietary solutions prevail in "non guaranteed bandwidth" networks and interworking with existing H.320 has to be through transcoding, thus customers' benefit is lost.  He also suggested to recommend two systems in the Recommendation or phasing the specifications.  There were some other voices to respect existence of Legacy LANs.  Rapporteur expressed his difficulty to reopen the issue after the conclusion of the previous two meetings (in Paris and Grimstad).   It was also pointed out that longer delay and echo is a potential problem in the "non guaranteed bandwidth" systems.  Mr. Skran further suggested to list identified technical problems in the "non guaranteed bandwidth" systems.  Rapporteur distributed a chronicle of H.32Z discussion (TD-14) to facilitate this work.

After the discussion, Rapporteur proposed to take the following actions to make a progress:

•	to list guaranteed bandwidth networks and their technical characteristics to clarify the notion of "guaranteed bandwidth" currently used in Draft H.32Z,
•	to invite proposals for moving forward when addressing "non guaranteed bandwidth" systems as well.  These should be posted by Christmas so that we can discuss the matterat the January meeting.

The meeting accepted this proposal.

Editor (Mr. G. Morrison) will revise the text reflecting the outcome of this meeting and post it at the reflector by November 27 (Tokyo time) for further consideration of the members towards the January meeting.

12. Joint sessions with MPEG

12.1 Documents

AVC-687, 688, 691, 693 and TD-17, 18 are input as proposal documents, while AVC-694 is input as a discussion document.

12.2 Representatives

	ITU-T EG		S. Okubo
	Requirements 	S. Okubo
	Video			G. Bjoentegaard
	Systems		S. Dunstan
	DSM			C-C. Li

13. Others

13.1 Future meetings till February 1995

Meeting	Date	Place	Sole sessions	Joint sessions with MPEG	
18th	Jan. 1995	Japan	Jan. 24-27	-	

13.2 Future meetings after February 1995

At the closing session, the meeting considered whether joint sessions with MPEG should be continued after this meeting.  Two areas of the future MPEG work were identified to be relevant to the ITU-T standardization; RTI (ISO/IEC 13818-9) and DSM-CC (ISO/IEC 13818-6).  Possibility of applying the common text to RTI was discussed, but the meeting could not reach a definite conclusion; some members stressed its necessity, but some others indicated that the matter should be carefully considered.

Closely related to the above discussion, the future meeting schedule has two alternatives; 

•	synchronized with MPEG meetings - March, July, October,
•	independent of MPEG meetings - May or June, October.

Due to lack of discussion time at the closing session, the meeting concluded that these matters be further studied through correspondence and finalized at the next meeting.

END

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Annexes

Annex 1	Documents for the Singapore meeting	
Annex 2	Group discussion on H.32X call phases and H.222.1 signalling	
Annex 3	Report of the discussion on AAL issues	
Annex 4	Specification for RTI	
Annex 5	Harmonization of ITU-T C&I and DSM-CC	
Annex 6	Specifications of H.32X hardware for the interconnection experiment	

Participants of the seventeenth meeting of the Experts Group 
for Video Coding and Systems in ATM and Other Network Environments
held in Singapore

Sole sessions	1, 3, 4 November 1994 
Joints sessions with MPEG	7-11 November 1994

Country 	Name	Organization	Sole	Joint	
Germany	Mr. Bernard Hammer	Siemens	X	X	
Australia	Mr. Stuart Dunstan	Siemens	X	X	
	Mr. King N. Ngan	Univ. of Western Australia		X	
Belgium	Mr. Olivier Poncin	BELGACOM	X	X	
Canada	Mr. Vahe  Balabanian	BNR		X	
Korea	Mr. Ki-Jin Kim	KAIST	X	X	
USA	Mr. CT Chen	Bellcore	X	X	
	Mr. Barry Haskell	AT&T	X (3,4)	X	
	Mr. Chia-Chang Li	AT&T	X	X	
	Mr. Jeffrey J. Lynch	IBM	X	X	
	Mr. Hayder Radha	AT&T	X	X	
	Mr. Richard Schaphorst	DIS	X (4)	X	
	Mr. Dale Skran	AT&T	X		
	Mr. Ali Tabatabai	Tektronix	X		
	Ms. Andria Wong	Bellcore	X	X	
Finland	Mr. Roy Mickos	Tampere University of Technology	X	X	
	Mr. Juha Pihlaja	Nokia	X		
France	Mr. Eric Gonfia	CNET	X		
Israel	Mr. Zeev Lichtenstein	ECI Telecom	X	X	
Japan	Mr. Kohtaro Asai	Mitsubishi	X	X	
	Mr. Keiichi Hibi	Sharp	X	X	
	Mr. Yuichiro Nakaya	Hitachi	X	X	
	Mr. Sakae Okubo	GCL	X	X	
	Mr. Yasuhiro Takishima	KDD	X		
	Mr. Tomoaki Tanaka	NTT	X		
	Mr. Hideyuki Ueno	Toshiba	X	X	
Norway	Mr. Gisle Bjoentegaard	NTR		X	
Netherlands	Mr. Roel ter Horst	KPN-PTT	X	X	
UK	Mr. David Beaumont	BT	X		
	Mr. Geoff Morrison	BT	X		
	Mr. Mike Nilsson	BT		X	
Singapore	Mr. Wong Liang Chun	Singapore Telecom	X	X	
	Mr. Vien-Chang M. Kan	Singapore Telecom	X	X	
	Mr. Kuan Choon Shiong	Singapore Telecom	X	X	
	Mr. Jason Tan	Singapore Telecom	X	X	
Sweden	Ms. Christel Verreth	Telia Research 	X	X