SC-02-12 meeting, San Francisco, 2008-10

Report of the meeting of the SC-02-12 Working Group on Audio Applications of Networks of the SC-02 Subcommittee on Digital Audio, held in San Francisco, CA., US., 2008-10-04

The meeting was convened by chair R. Foss.

The agenda and the report of the previous meeting, held in Amsterdam 2008-05-19, were accepted as written.

Open projects

AES-R10-2008 AES standards project report - Use cases for networks in professional audio

Intent: Review, Target: 2008
Current goal: Status report, Goal date: continuing

Richard Foss proposed that this report be embellished and expanded with specific scenarios.

Development projects

AES-X075: IEC TC100 Liaison for IEC 61883
J. Yoshio reported for IEC TC100. Work on channel assignment in IEC 61882-6 is still under discussion. Firstly the A/M protocol has to be amended in the 1394TA, and then the 61883-6 protocol can be amended accordingly. Any amendment will depend on the development of IEC 62574 General channel assignment of multi-channel audio. These new channel specifications are being worked on. An amendment could be made to the A/M protocol in January 2009.

He also reported that in TC100 a new Technical Area (TA11) is being formed to look at quality of audio and multimedia issues, in particular lip-sync issues. This has particular implications for internet video.

AES-X101: Data Type, Properties, and Method Definitions for Audio Device Application Program Interfaces (API)

Intent: Report, Target: 2006
Current goal: PWD, Goal date: 2009-01

There was some discussion about how to move forward with the current proposals as provided by K. Dalbjorn. A decision was made to refer the document to the SC-02-12-G task group, who would consider whether the proposals could be integrated into the AES-X170 specification, or be referred to by the specification. Dalbjorn suggested that a reference to the current work would be preferable, since the scope of AES-X170 was already quite extensive.

AES-X132: Synchronisation of audio over IEEE 1394

Intent: Standard, Target: 2008
Current goal: Sec-formatted PWD, Goal date: 2008-10

M. Yonge commented that this is a complex document to get into standards form, and is still 'in the queue' awaiting secretariat formatting.

AES-X137: Liaison with 1394 Trade Association (1394 TA)

Intent: Liaison, Target: Continuing
Current goal: Status report, Goal date: Continuing

M. Lave reported that there has been work done within the 1394TA to combine all the IEEE 1394 standards documents into one document. This document is currently going through the IEEE standardization process. There is a new PHY-Link interface. The enhanced twisted pair connection has been included (s200 and s400). The pairs are compatible with gigabit Ethernet. The beta specifications for s1600 and s3200 are also included in the new specification.

Lave commented on the pro-audio group within the 1394TA that had worked on use cases for pro audio. The 1394TA has decided to fold the pro audio group into the AV/C working group.

There is an upcoming meeting of the 1394TA in Munich, and at this meeting there will be an interoperability test session enabling manufacturers to test for interoperability. [This information was communicated to all SC-02-12 and SC-02-02 membets by the secretariat.]

There was some discussion about work within the 1394 TA on AV/C over IP. M. Mora indicated the problems associated with bridging the AV/C protocol, and Lave said that he would find out more about this topic and report to the group on it.


Liaison with Ethernet AVB
Foss indicated that there was a new liaison with the Ethernet AVB working groups. Mora will represent the Ethernet AVB group in this liaison, and he reported on the activities of the various working groups.

  • The current specification document for IEEE 1722 that describes stream formats, is on the document site, and is currently out for IEEE comment. The editor will receive comments.
  • The document for 802.1as (synchronization) is also currently out for comment.
  • The 802.1Qat document (the stream reservation protocol) has a lot of work to be done.
  • 802.1Qav (forwarding and queuing enhancements) is well on its way.
  • There is a face to face meeting for p1722 in San Jose on October 23, and a more general session for all working groups in New Orleans in January 2009.

Mora indicated that many of the meetings are attended by people with networking rather than audio expertise, and he made an appeal for those with audio expertise to attend. Yonge expressed the need for a more formal liaison with the Ethernet AVB groups, in particular to acquire relevant documents. Mora suggested that he contact T. Jeffrey and will provide him with a contact address.

New projects

AES-X170: Integrated Control, Monitoring and Connection Management for Digital Audio Networks
Foss discussed the progress of AES-X170, a nascent project aimed at the standardization of an integrated connection management and control protocol. Task group SC-02-12-G, has been tasked with the fulfillment of the goals of this project.

R. Gurdan, the task group leader, gave an overview of the discussions at the task group meeting. He indicated that the major features of a protocol called XFN had been discussed, and that a preliminary document is on the document site. He described how a number of use cases had been proposed and what features within the protocol dealt with these use cases. There was a proposal that use cases be used as a means of guidance towards protocol adoption, whereby users could see the strengths and applicable areas for the range of available connection management and control protocols.

There was a discussion about enhancing the current use case document to provide attributes that control protocols should have, in order to comply with the requirements of the various sections - recording, live sound, and install. It was decided to create questionnaires that laid out desirable attributes for particular sound control use cases. Foss agreed to request appropriate scenarios for the questionnaire and to coordinate their insertion into the use cases document.

P. Treleaven spoke about the applicability of the multi-part IEC 62379 Common Control Interface for networked digital audio and video products to broadcast, and how IEC 62379 also addressed video. He also indicated the importance of reviewing the SNMP-based approach of IEC 62379, and determining whether the proposed protocol could integrate with this work. Foss indicated that there were comments from J. Grant regarding the proposed protocol and IEC 62379, and that with Grant's permission he would place them onto the document site.

Foss requested that the word 'media' be inserted into the title of the project. Yonge suggested that the title be changed to "Integrated Control, Monitoring and Connection Management for Digital Audio and other Media Networks"

New business

There was no new business

The next meeting will be scheduled in conjunction with the AES 126th Convention in Munich, Germany, 2009-05.

AES - Audio Engineering Society