ITU-T Telecommunication Standardization Sector	Document AVC-673R
Study Group 15	22 July 1994
Experts Group for Video Coding and Systems
in ATM and Other Network Environments

Source:	RAPPORTEUR (Sakae OKUBO)	
Title:	REPORT OF THE SIXTEENTH EXPERTS GROUP MEETING IN GRIMSTAD (13-22 July 1994) - Part I and Part II	
Purpose:	Report	

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

Part I	General
Part II	Sole sessions
Part III	Joint sessions (see AVC-674R)

Part I General

The sixteenth meeting of the Experts Group was held in Grimstad, Norway, as follows;

•	ITU-T sole sessions during 13-15 july at the kind invitation of Norwegian Telecom Research, 
•	Joint sessions with ISO/IEC JTC1/SC29/WG11 (MPEG) during 18-22 July at the kind invitation of Norwegian Standards Association (NSF).

Part II  Sole Sessions

Contents

1. 	Introduction
2. 	Documentation
3. 	Review of the previous meetings
4.	Video matters
5. 	H.222.1 and H.222.0
6. 	H.32X
7. 	H.32Y
8. 	H.32Z
9.	AAL
10.	Timebase recovery
11.	Work plan and work method
12.	Joint sessions with MPEG
13.	Others

1. Introduction

The ITU-T sole sessions were held at Sorlandet Hotel and Conference Center during 13-15 July 1994 at the kind invitation of Norwegian Telecom Research.  At the opening session, Mr. Gisle Bjoentegaard made a welcoming address on behalf of the hosting organization.  

At the end of the sessions, Chairman thanked the hosting organization for providing an opportunity to meet at a nice season of the year, excellent meeting facilities and secretarial support.

We had also a closing session on 22 July to review both sole and joint sessions.

It is noted that this time the discussion of H.222.1, H.32X, H.32Y and H.32Z was co-chaired by Rapporteur and each Editor; Mr. Stuart Dunstan, Mr. Chia-Chang Li, Mr. Hayder Radha and Mr. Geoff Morrison.  It is also noted that relevant parts of this meeting report were drafted by the Editors.

2. Documentation (TD-2)

For the sole sessions, 42 AVC-numbered documents and 11 temporary documents have been made available as listed in Annex 1.

3. Review of the previous meetings 

Rapporteur presented the major outcome of the following meetings, drawing attention of the members to items of the Experts Group concern;

1) Experts Group March meetings in Geneva/Paris (AVC-631R, 632R, 633R)

•	AAL1 and AAL2 discussion for video transport services
•	network adaptation discussion and protocol reference model
•	jitter consideration in the ATM environments

2) SG15 May meeting in Geneva (AVC-637, 638, 639)

•	framework for audiovisual/multimedia Recommendations
•	common text approach to H.222.0|ISO/IEC 13818-1
•	response to the items on which we sought guidance of Working Party 1/15

It has been noted that the IVS Baseline Document contains "Service Requirements" as Annex 7 which lists a set of requirements for the audiovisual communication systems in ATM environments.  Since it is as was produced in 1991, Rapporteur undertakes its updating to clarify the objectives of the Experts Group work.

3) JCG/AVMMS May meeting in Geneva (AVC-652)

•	relationship between international standardization bodies (ISB) and consensus forming bodies (CFB)
•	study of interactive multimedia services
•	profiles of multimedia terminals

4) MPEG June meeting in Atlanta (AVC-643R)

•	DIS and additional work for stipulating interface characteristics at the junction of MPEG decoder and network/DSM adaptation
•	jitter tolerance
•	VBR aspects

4. Video matters

4.1 Picture format parameters for Main Level (AVC-646)

AVC-646 proposes to extend the frame rate upper bound of the Main Level from 30 to 60 for pro-scan sources within the same upper bounds for luminance sample rate.  This proposal does not include extension of field rate of interlaced source such as 120 fields per second 

Considering that 

•	the pro-scan will be widely used by audiovisual/multimedia applications in the future, and
•	required resource of the decoder does not change due to this extension of the frame rate upper bound,

but recognizing that the standardization is now in the very last stage, the Experts Group supports this proposal on the proviso that implementers of the decoder do not have difficulty to accommodate this change of the specifications.

As to the implementers reaction, we heard one explicit voice of difficulty during the meeting.  Since many more implementers will come next week, we will await their reactions before making our firm position.

It was noted that the frame rate is currently defined in discrete values and that an indication will be required to distinguish between 60 fields per second interlaced source and 60 frames per second pro-scan source at the decoder.

Simulation result pictures related to the description of AVC-646 were demonstrated by NTR; comparison of coding and displaying interlaced pictures and pro-scan pictures.

4.2 Video frame synchronous signals (AVC-656, 665, 668)

AVC-665 proposed to standardize a method to send the closed caption signals while AVC-656 and 658 pointed out the need to specify a method to send C&I signals; both type of signals are tightly coupled with corresponding video frames.  The channel and encoding methods of such video synchronous signals are to be decided.

We recognize that there will be more applications for video frame synchronous auxiliary or control signals other than closed caption and C&I.  Furthermore, a control channel is in any case required (see §5.3 of this report).  We seek a separate systems stream solution rather than a video stream solution since it provides necessary synchronization and is more flexible.  After considering the need to cover both PS and TS as the H.32X multiplex scheme, the meeting agreed to find a PES solution which is common to PS and TS and allows to identify different applications.

Mr. Paul Haskell undertook to draft a solution with cooperation of other volunteers.  The outcome is in Annex 2 which was approved by the meeting.  This will be submitted to the joint sessions for consideration and seeking advice toward the November meeting.  

Contributions on the descriptor syntax to be included in H.222.1 are solicited toward the next meeting.

During the discussion, it was clarified that the degree of synchronization between video and closed caption is not more strict than that of the lip-sync.

5. H.222.1 and H.222.0

5.1 Priority (AVC-636, 658)

Documents AVC-636 and 658 proposed to define primitive parameters for priority and error indication at the boundary of H.222.1 and AAL layers.  The meeting agreed to do so and send SG13 a request for action in AAL.  It was also agreed that the linkage between the higher layer priority request and the primitive parameter setting at the AAL-SAP should not be tight; it should be left to the choice of applications.

5.2 Bit error /cell loss handling (AVC-635, 657, 672)

Document AVC-635 gave the ATM network performance assumptions to make our progress in the study of network adaptation solutions.  AVC-672 provided a backing material regarding the cell delay variation.  It should be noted that these assumptions are our own yardstick in the lack of definitive performance figures and do not represent official views from any national or international standardization bodies.  The meeting agreed to send this to SG13 for comments and to SA&A of The ATM Forum for information.

Some questions were raised on the end-to-end delay figures in AVC-635, particularly if we consider B-ISDN support of ordinary telephone services.  This point needs advice of SG13.

Mr. Radha drew attention of the members to that definition of SECB (Severely Errored Cell Block) may need our consideration from the point of audiovisual communication services support and noted that cell losses are treated as part of Severely Errored Second, thus not counted in BER.

Document AVC-657 presented analysis of bit error impacts on the audiovisual communication in terms of mean error free time and concluded that bit error correction is indispensable even in the best case scenario which is given in AVC-635.  The meeting shared this conclusion.  Mr. Tanaka suggested Case 1 (AAL1 short interleaver) or Case 2-1 (FEC in the H.222.1 specific layer) for the generic AAL solution, and Case 3-2 (FEC in AAL SSCS) or Case 4 (interleaver in AAL for 47 TS packets) for the TS specific AAL solution.  It was clarified that the double correlated errors in a cell due to payload scrambling can be recovered in each of these solutions.  The meeting agreed to the preference of seeking generic AAL solution(s).

The document also raised a question of matching between AAL5 and bit error correction; the meeting reached a view that the AAL5 is only appropriate in the low bit error environments.  The issue of more general bit error correction in VBR supporting AAL2 awaits contributions.

Mr. Dunstan made a comment that the mean error free time in AVC-657 does not take into account the effect of error concealment; there are cases where bit errors are not visible because of inherent or intentional error resilience.

5.3 Multiplexing of ITU-T specific channels (AVC-656)

Document AVC-656 pointed out the need to provide a mechanism in H.222.0 for accommodating ITU-T application specific audio, video, data and control channels.  The meeting discussed the proposal in the document and reached a conclusion as in Annex 2 to this report (see §4.2 above).

As to the method for synchronous mode switching, the issue should be raised in the joint sessions with MPEG for seeking advice.

5.4 Multiple VC solution (AVC-640, 664; TD-6)

Documents AVC-640 and AVC-664 discussed use of multiple VCs being more appropriate for some cases; the former addresses T.120-series telematic and conference control information, the latter audiovisual communication information.  TD-6 is an input from SG8 during our meeting which contains recent SG8 meeting outcome.  

The meeting took note of the discussions in these documents and solicits contributions regarding pros and cons for use of single VC vs multiple VCs toward the next meeting.  It is also suggested the contributions address whether single VC and multiple VCs solutions coexist or migrate from one to the other and their interworking.  Motivations for multiple VCs are summarized in AVC-664 as:

•	Different Quality of Service in ATM may be defined for different signal components (elementary streams), being conveyed in different VCs, e.g. for layered coding.

•	Routing of programs and elementary streams of programs by ATM switches without need of H.222 equipment as network elements.

•	Multipoint control unit operating at ATM layer instead of H.222 layer.

Representation of the multiple VC consideration in the protocol reference model also needs further work.

As to the "transparency" for the COTS in a single VC configuration, which has been raised by SG8, Mr. Dunstan commented that one way is to provide transparent Class C service by reducing video rate to cope with bursty nature of the COTS data traffic.

5.5 Communication control procedures H.24X (AVC-641, 655)

The channel for this purpose was discussed in the context of video frame synchronous C&I, ITU-T application specific channel allocations (see §4.2, §5.3 and Annex 2 of this report).  In case of asymmetrical channel configuration, the return channel may use AAL5.

The meeting agreed to the following guideline for developing communication control procedures:

•	to consider both the "capabilities and command" approach and the "ACK-NACK" approach, at least at the initial stage of study; the latter is thought to be more robust and allow easier transition of state machines ,

•	to cover both interactive and broadcasting type of communications; communication channels may be symmetrical, asymmetrical or completely unidirectional.

As to the selection of PS or TS at the start of a call, the meeting reached a common understanding that conveying it through the signalling channel by e.g. LLC/HLC is appropriate.  There was some discussion on the underlying question whether H.32X should support PS or TS or both.  Several indications were given to the market support of TS, but it was also expressed that use of PS is attractive for single programs in the ATM environments, particularly in computer applications.  Rapporteur desired to narrow down the alternatives; contributions with strong position may be needed to achieve it.

5.6 Protocol reference model (Annex 3 to AVC-632R)

The model in Annex 3 to AVC-632R is still valid as far as the contributions for this meeting have been considered.  Only wording improvements have been identified; "timebase recovery" in "Possible AAL2/5 functions" should be removed, that in "AAL type 1 functionalities" should be replaced with "transmission clock recovery".

Rapporteur requested members to make progress in definite allocation of functionalities to each constituent element in the protocol reference model.

5.7 Draft Recommendation (AVC-660)

Document AVC-660 is the draft of Recommendation H.222.1 which was input to the SG15 meeting in May 1994.

The meeting agreed to adopt the proposed protocol description approach in Sections 8 and 9, recognizing that it helps designing the implementation.

The following suggestions were also given to the current draft:

•	Jitter removal is not purely an implementation matter, but a protocol issue.

•	Naming of HPS and HTS will be misleading that H.222.1 defines another set of PS and TS different from those in H.222.0.

•	Draft Recommendation H.222.1 will prepare a placeholder for the multiple VCs, but with indication of "for further study".  It could be handled as multiple instances of H.222.1.

•	Inclusion of the protocol reference model (as in Figure 1/AVC-639) was suggested, but this is more appropriately to be part of H.32X.

•	Security functions provided by H.222.0|ISO/IEC 13818-1 are more than encryption; entitlement control and management are also included.  Support of H.233 and H.234 or their extensions should be considered as well.

Mr. Dunstan agreed to update the draft reflecting the above discussion with indication of action points in form of Editor's comments and distribute it before 9 September 1994.

5.8 VBR issues (AVC-647; TD-3,4)

After short discussion due to time availability, the meeting recognized that VBR operation in PS or single program TS has less problems but that in multi-program TS needs elaborate techniques.

5.9 Report on detailed discussion

Mr. Dunstan's report containing the details of discussion on H.222.1 related topics is found in Annex 3 to this report.

6. H.32X

6.1 Framework (AVC-666, §3/AVC-659)

Document AVC-666 provided discussion materials addressing communication mode, terminal type and interworking scenarios.  Specifications for the hardware trials presented in §3/AVC-659 were also used for this discussion since they should reflect essential part of the H.32X specifications.

The meeting generally supported the direction proposed in AVC-666, giving the following suggestions:

•	Since characterization of H.32X terminals are multi-dimensional, use of the attribute method such as employed for the definition of ISDN services may help us.

•	Characteristics of control channel may be part of the attributes.

•	Symmetrical configuration may be defined as both end terminals having the same set of capabilities.  Asymmetrical cases including receive only should be considered from the outset if we take into account potential services and B-ISDN capabilities.

•	Definition of Type A in H.32X is not supported.  Interworking modes of operation should instead be specified (see §7.2 of this report).

•	Since the transfer rate is flexible in B-ISDN, the operating bit rates of the H.262 encoder should be at any bit rates below the declared maximum value as is the case of H.262 decoders.

•	Indication of a preferred receiving mode from the receiving side should be considered.

•	Specification for the video encoder should be to produce a bitstream compliant to a certain Profile @ Level.  It needs not to support whole tools of the defined Profile @ Level.

•	The protocol reference model should be included in Recommendation H.32X.

As to the hardware trial specifications, the meeting suggested the following:

•	Interconnection of 525/625 video: Some codecs are expected to send only one format, but receive either format.

•	Audio: MPEG-1 mandatory, MPEG-2 optional (note that MPEG-2 audio is backward compatible with MPEG-1 audio).

•	Multimedia multiplex: decoder supports PS and TS, but encoder can use either of them.

•	AAL: four combinations of (CBR, VBR) and (AAL1, AAL5) are possible, leaving open the choice of one or more of the combinations at this moment.

•	Communication procedures: testing a minimum set is desirable.

•	User network signalling: PVC at the initial stage to avoid additional verification for signalling.

6.2 Draft Recommendation (AVC-661)

Document AVC-661 is the draft of Recommendation H.32X which was input to the SG15 meeting in May 1994.

Mr. Li agreed to update the draft reflecting the above discussion with indication of action points in form of Editor's comments and distribute it before 9 September 1994.

6.3 Report on detailed discussion

Mr. Li's report containing the details of discussion on H.32X related topics is found in Annex 4 to this report.

7. H.32Y

7.1 Framework  (AVC-634, 653)

Document AVC-634 gave Mr. Yamazaki's clarification on the circuit emulation.  The meeting appreciated this informative input.

The following comments were given to the analysis for bit error handling in AVC-653 which is based on the network scenarios in AVC-635:

•	BCH decoding in the H.261 decoder is optional, hence it can not always be counted as a measure to cope with bit errors, though it is mostly supported by the equipment in the market.

•	Delay sensitive audio applications may not accept the short interleaver solution, hence if the bit error performance of a 64 kbit/s channel is not sufficient for the ATM portion, a general bit error correction solution is required.

Related to the use of cell loss correction in the ATM part of connection for the B-N interworking, a question was raised how the Interworking Function can recognize the audiovisual call, particularly when the N-ISDN side originates a call.  It might be possible for the IW activate the short interleaver AAL1 by interpreting LLC/HLC or AAL negotiation, but it is against the principle that the network is service independent.

These should be communicated with SG13 seeking their advice.

7.2 Terminal type (AVC-667)

The meeting agreed that definition of the H.32Y terminal type should be the same as that of H.320.

There was some discussion on the relationship between  H.32X terminal, H.32Y terminal and modes of operation which each of them should support.  Since the H.32X terminal is required to interwork with H.320 terminals connected to the N-ISDN, it should support some interworking modes of operation in addition to the broadband specific modes of operation (e.g. using H.262 video, MPEG audio, H.222.0 multiplex).  Terminal configuration of H.32X and H.32Y terminals is illustrated in Figure 1.

Figure 1  H-series audiovisual communication terminals

A minimum set of interworking modes of operation which H.32X terminals should support has been agreed to include the following transfer rates;

•	2B (including 1B by definition), 
•	H0, 
•	H11, and
•	H12.

This is based on the consideration that the specification should reflect the typical type of H.320 terminals which are currently installed and with which the H.32X terminal talks, and that the regional restriction can be overcome by utilizing the B-ISDN characteristics.  This and other specifications are contained in Annex 5 to this report together with H.32Y discussion summaries.

7.3 Draft Recommendation (AVC-662)

Mr. Radha agreed to update the draft reflecting the above discussion with indication of action points in form of Editor's comments and distribute it before 9 September 1994.

7.4 Editor

Mr. Hayder Radha agreed to take the editorship of H.32Y from this meeting which had provisionally been undertaken by Rapporteur due to the absence of volunteer.

8. H.32Z

8.1 Framework (AVC-648, 649, 650, 671; TD-9)

The major discussion centred on the scope of H.32Z.  A provisional agreement from the Paris meeting was that H.32Z be for "bandwidth guaranteed LANs" (§7.2/AVC-632R).  Document AVC-648 proposed that "best effort" networks should also be supported, primarily through the use of RTP (Internet Real Time Protocol) in place of H.221.  Accompanying documents AVC-649 and 650 gave further technical information on RTP and other major issues including ISDN-LAN gateways, ISDN-LAN address conversion, mapping of H.320 on RTP, mapping RTP on LAN, respectively.

It was clarified that RTP uses a separate "virtual circuit" for each media component such as audio, video, etc.  Timing recovery and media synchronisation are accomplished through time stamps which are functionally similar to SRTS and require a common network clock at both ends.

Several participants expressed concerns about the Quality of Service issues which arise from the absence of resource reservation.  The general theme was whether ITU-T should have its name associated with the variable and sometimes low quality they feared would arise and become even more prevalent as usage increases.  It was reported that some experiments had been prematurely ended by LAN management functions terminating the transmissions.  The rebuttal of QoS arguments was that it is the user's choice and the strategy for H.320 terminal standardization has been to guarantee interworking but to leave the cost/performance trade-off to the choice of designers.

Document AVC-671 was also supportive of extending the scope of H.32Z to include "non-guaranteed bandwidth" LANs and suggested splitting the Recommendation into two parts.

In counter to the above contributions, Mr. Morrison introduced an extract (see TD-9) from the draft of IEEE802.9a due to be submitted for letter ballot in August 1994.  This draft standard is a specific example of a "guaranteed bandwidth" LAN and can provide isochronous services instead of, or in addition to, those of ISO/IEC 8802-3 (=IEEE 802.3).  Many advantages for the use of such an approach were claimed:

•	current H.320 performance is maintained from end to end. No QoS problems.

•	gateway devices for the LAN-ISDN gateway will be general purpose, not H.32Z specific.  This has benefits in terms of availability (larger market is more attractive for manufacturers to enter), lower unit price (larger manufacturing volume) and lower per user cost (same device serves many users, not just H.32Z terminals).

•	extension of the ISDN including the D channel to the H.32Z terminal rather than terminating it at the ISDN-LAN gateway avoids or simplifies some issues concerning any necessary connection approval of the gateway device to the ISDN.

•	much superior support for higher rate real time signals such as MPEG-1 and MPEG-2.

•	an evolutionary approach suitable for upgrading the majority of existing LAN installations without needing rewiring.  Attractive to many LAN users already running out of capacity irrespective of H.32Z.

The meeting agreed to confirm the provisional agreement at the previous meeting that only "bandwidth guaranteed" LANs would be explicitly covered by H.32Z.  It was recognised that for "best effort" networks, equipment may be offered which achieve performance levels acceptable for some users and achieve interworking with ISDN based H.320 terminals by means of a dedicated custom gateway.  However, these would be "at the user's risk" and not recommended by ITU-T.

Further clarification of "bandwidth guaranteed" and improved terminology is requested for the next meeting.  Such bandwidth guaranteed networks can be either circuit based or packet based.

Proposals should also include information on call set up matters such as terminal numbering.  We need a network configuration model to make progress on this matter.

8.2  Draft Recommendation H.32Z (AVC-663)

Document AVC-663 was presented as the draft H.32Z skeleton given to SG15 WP1/15 at their May 1994 meeting.  There was a suggestion that because H.32Z may be very similar to H.320 a delta Recommendation may be the most appropriate form.  A major difference is likely to be the network interface.  In the event of several alternatives it may be sufficient that H.32Z includes only a single logical interface and leaves the physical interfaces to the respective LAN specification documents.

Mr. Morrison agreed to update the draft reflecting the above discussions with indication of action points in form of Editor's comments and distribute it before 9 September 1994.

9. AAL

9.1 AAL1 (AVC-651)

Document AVC-651 reported preliminary experiment results on ATM transport of H.320 signals through AAL1 in UK.  Mr. Beaumont advised the meeting of interconnection tests being planned between UK and France in the near future.  Comparison of the current adaptive clock method and an SRTS method is also intended.  Further reports of the experiment are welcome.

9.2 TS delivery AAL (AVC-658)

See §5.1 of this report for defining primitive parameters at the AAL SAP.

9.3 AAL2 (TD-4)

This type of AAL is a placeholder at the present.  It is deemed that its progress owes largely to the work of this Experts Group as a potential user.  Contributions are solicited for defining requirements to AAL2.

10. Timebase recovery

10.1 Dejittering for ATM cell delay variation (AVC-642)

Document AVC-642 presents general solutions for timebase recovery in the jitter prone environments such as ATM.  The meeting reviewed this outcome of the Atlanta meeting and agreed to send it to the meeting of SA&A in The ATM Forum.

Mr. ter Horst pointed out that implementation related description comparing PS and TS should have been more carefully worded.  Rapporteur will bear this comment in his mind for future opportunities to make such statements.

10.2 Speeding up timebase recovery (AVC-647)

Document AVC-647 provided information on a method of speeding up the timebase recovery by estimating the cell arrival time.  This technique may be implemented in the decoder without affecting the specifications in the standard.  Its implication is, however, jitter removal is not required in the network adaptation portion.

Mr. Li suggested that transmission rate which is necessary for VBR timebase recovery in this method can be made known by external means if the call set up includes such information.

11. Work plan and work method

11.1 Approval process for H.262, H.222.0 (AVC-669, 670)

Rapporteur clarified the process of obtaining approval of ITU-T for the common text Recommendations H.262|ISO/IEC 13818-2 (Video) and H.222.0|ISO/IEC 13818-1 (Systems) in AVC-669.  Members are requested to send their comments on the current drafts to Rapporteur by 10 October 1994 so that he can integrate them into a single SG15 contribution for consideration of the Singapore meeting.

Since one of the necessary conditions for the approval is to clear the intellectual property handling, members are requested to follow the ITU-T code of practice as described in Annex to AVC-670.  As to Table 1/AVC-670, Mr. Bjoentegaard confirmed that NTR's "patent information" cell should read "*".

11.2 Hardware trials (AVC-659; AVC-651)

Document AVC-659 provided information on the hardware trial plan in Japan, addressing date, testing items, experimental system configuration and specifications.  The meeting reviewed this plan and gave some suggestions on the specifications as in §6.1 of this report.  For the remaining topics, the meeting felt the plan gave a good starting point.

Participation in the hardware trials and contributions to materialize the trial plans are requested.

11.3 Document and information distribution

The meeting requested Rapporteur to issue lists of distributed documents so that the distribution points in respective countries can take necessary actions for distribution inside the country.

After having reviewed the e-mail distribution of the documents, the meeting confirmed the agreement at the Daejeon and Paris meetings (see §9.2.3/AVC-498R, §9.2/AVC-632R); namely interchange formats should be 

•	uuencoded Word for Windows 2.0 file (not compressed),
•	not more than 80 characters in a line,
•	plain text version as well as formatted version.

11.4 Correspondence work between this meeting and the next meeting

Since the November meeting is crucial for proposing frozen draft Recommendations at the February 1995 meeting of SG15, progress should be made through correspondence.  Editors are requested to lead this correspondence work regarding respective Recommendations in charge.

12. Joint sessions with MPEG

12.1 Documents

The following documents are input to the joint sessions:

•	From the Experts Group	TD-7 revised
•	From individual sources	AVC-646, 647, 654, 655, 656, 664, 665, 669, 670.

As to the proposal from the Experts Group, this meeting is understood as an opportunity for consensus forming toward the November meeting.

12.2 Representatives

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

13. Others

13.1 Communication with SA&A of The ATM Forum

The meeting agreed to send AVC-635 and AVC-642 for information to SA&A of The ATM forum which meets in the week of July 18.  Rapporteur will get contact with Mr. Jeffrey Lynch.

13.2 Correspondence with SG8 and SG13

Rapporteur will draft correspondence letters with help of Mr. Dunstan on the following items:

Destination	Request for 	Contents	
SG8	consideration	Response to SG8's comments contained in TD-6 regarding multiplexing telematic information in audiovisual communication call	
SG13	action	priority and error indication primitive parameters at ALL-SAP	
SG13	comments	network performance assumptions contained in AVC-635	
SG13	advice	end-to-end delay, particularly for support of telephone as part of audiovisual services 	
SG13	advice	identification of audiovisual services at the interworking function and terminal adaptor to activate error correction	
SG13	consideration	general bit error correction as discussed in §7.1	
SG13	clarification	short interleaver, circuit emulation and support of SDT 	

11.3 Future meetings till February 1995

Meeting	Date	Place	Sole sessions	Joint sessions with MPEG	
17th	Nov. 1994	Singapore	Nov. 1, 3, 4	Nov. 7-11	
18th	Jan. 1995	Japan	later January (note)	-	

Note - The week of January 16 or 23 is intended considering that SG15 will meet from February 6, 1995.

END

Annexes

Annex 1	Documents for the Grimstad meeting	
Annex 2	Support for ITU-T Control and Indication Signals	
Annex 3	Summary of discussions on H.222.0 and H.222.1	
Annex 4	Summary of H.32X Discussions	
Annex 5	Summary of H.32Y Discussions and H.320/H.32X Interoperability Issues	

Participants of the sixteenth meeting of the Experts Group 
for Video Coding and Systems in ATM and Other Network Environments
held in Grimstad, Norway

Sole sessions	13-15 July
Joints sessions with MPEG	18-22 July

Country 	Name	Organization	Sole	Joint	
Germany	Mr. Bernard Hammer	Siemens	X	X	
Australia	Mr. Stuart Dunstan	Siemens	X	X	
Belgium	Mr. Olivier Poncin	BELGACOM	X	X	
USA	Mr. Bahman Amin-Salehi	Bell Atlantic	X	X	
	Mr. Richard Grinnell	PictureTel	X	X	
	Mr. Barry Haskell	AT&T	X	X	
	Mr. Paul Haskell	CLI	X	X	
	Mr. Chia-Chang Li	AT&T	X	X	
	Mr. Hayder Radha	AT&T	X	X	
	Mr. Gary Rekstad	NCS	X	X	
	Mr. Tony Wasilewski	Scientific Atlanta	X	X	
	Ms. Andria Wong	Bellcore	X	X	
Finland	Mr. Roy Mickos	Tampere University	X	X	
	Mr. Juha Pihlaja	Nokia	X		
France	Mr. Philippe Boucheron	CNET	X		
	Mr. Stephane Lemaire	CNET	X		
	Mr. Bruno Loret	CNET		X	
Japan	Mr. Kazuhiro Matsuzaki	Mitsubishi	X	X	
	Mr. Sakae Okubo	GCL	X	X	
	Mr. Tomoaki Tanaka	NTT	X		
	Mr. Hideyuki Ueno	Toshiba	X	X	
Norway	Mr. Gisle Bjoentegaard	NTR	X	X	
	Mr. Robert Danielsen	NTR	X	X	
	Mr. Karl Olav Lillevild	NTR	X	X	
Nethrelands	Mr. Roel ter Horst	KPN-PTT	X	X	
UK	Mr. David Beaumont	BT	X		
	Mr. Geoff Morrison	BT	X		
	Mr. Mike Nilsson	BT		X	
Sweden	Mr. Per Tholin	Telia Research 	X		
	Ms. Christel Verreth	Telia Research 		X