SC-02-12 meeting, Rome 2013-05

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 Rome, Italy, 2013-05-06

The meeting was convened by chair R. Foss.

The agenda and the report of the previous meeting, held in San Francisco, 2012-10-28, were accepted as written. Projects assigned to this group but not mentioned here had no action requested or required - see for details.

Open Projects

AES58-R: Review of AES58-2008: AES standard for digital audio - Audio applications of networks - Application of IEC 61883-6 32-bit generic data
Discussion: Foss indicated that this related to the streaming of control data (apart from MIDI) over IEEE 1394, and that the standard was complete. It would also be of relevance to AVB. The intent target for this review is this year. So the proposal was to reaffirm this standard unless an alternative proposal to revise it arrives before 4 weeks has elapsed.

AES64-R: Review of AES64-2012, AES standard for audio applications of networks - Command, control, and connection management for integrated media
Discussion: Richard Foss indicated that M. Yonge's comments on parameters with Global Unit values were being addressed, and that updates related to parameter snapshots and bulk parameter 'pushes' for monitoring purposes would be presented to the working group in the near future.

AES-R10: AES standards project report - Use cases for networks in professional audio
Discussion: Michelle Daniels and Peter Otto have found the latest work from the late N. Brock related to this report. Brock had updated the report with edits and information relating to telematics use cases. K. Gross agreed to look at the report, edit it and possibly update it further. He is currently busy with similar work in conjunction with the IETF and other organizations. Anyone else with an interest in this report is encouraged to contribute.

Development Projects

AES-X075: Liaison with IEC TC100 for IEC 61883
Discussion: J. Yoshio provided a liaison report that contained an IEC standards update and described work done on TC100 specifications related to SC-02-12.

1. IEC standard update
1.1 IEC 61883-6 (A/M Protocol) Edition 3.0 status RVC (Result of Voting on CDV) was circulated on 22, March. It is approved with some editorial comments. PL solves comments and makes final document. The revised items for the edition 3.0 are multichannel assignment, copy control information of DTCP+, and editorial corrections.

1.2 IEC 61883-8 (BT. 601) Edition 1.0 Amendment 1 status. The CDV is approved, and editorial comments were solved. The final document was submitted and it will be published. The amended items are copy control information of DTCP+.

1.3 IEC 61883-1, 2, 3, 4, 5 and 7 status. The stability date of all of other parts is 2013-05 or 2014-03, they will be reviewed.

2. TC100 liaison with IEEE1722. TC100/TA4 sent a liaison statement to IEEE 1722a chair in March. IEEE 1722 chair discussed this liaison request with IEEE members in advance, and they were in favour of it.

History: At the TC100 plenary meeting in October 2012, TC100 approved the request to establish the liaison between TC100/TA4 and IEEE 1722 regarding AVB and IEC 61883 series.

AES-X137: Liaison with 1394 Trade Association (1394 TA)
Discussion: M. Lave indicated that he would be the liaison for the 1394 TA. He said that there has not been any new work related to our group. He pointed out that IEC 61883-6 is based on the 1394TA A/M protocol. The 1394 TA group is focusing their standards activities on new areas and not much on audio where the standards are stable and mature. S. Heinzmann asked whether the latest IEC 61883-6 document was on the working group site. M. Yonge suggested that he (Mark Yonge) contact the 1394TA chair to get the latest A/M protocol specification.

AES-X170B: AES standards report - supplementary information on AES-X170A, 3CIM
Discussion: Foss agreed to review the document.

AES-X192 High-performance streaming audio-over-IP interoperability
Discussion: K. Gross indicated that a draft standards document had been produced by the task group for perusal by the working group. M. Yonge said that it was now up to the working group to review and comment on the document within a month. Gross said that he typically received free format emailed comments and would put these into a spreadsheet. Yonge said that the IEC had a formal comments document and suggested that the working group use this. Yonge said that he would create an AES 'comment' form.

Gross indicated that there is a dependency on an IETF document related to clock sources, and also three informative references.

AES-X210A Open Control Architecture - Framework and object model
Discussion: J. Berryman, the task group leader, presented a report on the task group meeting that was held the previous day. He indicated that the draft document is quite mature. There would be teleconferences starting up on the 9th May, and these would be held every 2 weeks. This document should be complete within a few weeks. The complete set of three documents should be complete by spring 2014.

There was a discussion about interoperability between the AES-X210 specification and AES64. S. Heinzmann suggested that a document be produced that specified the mapping between the two protocols.

AES-X210x Open Control Architecture - Class tree
Discussion: There were a number of updates to the class tree within the OCA Alliance. There would be annual updates to the class tree.


Liaison with SMPTE S. Scott indicated that there is a lot of similar work to this working group being done in SMPTE. Yonge indicated that there is already a formal liaison with SMPTE, but that information now needs to flow between AES and SMPTE. P. Treleaven suggested that there be document exchange between the two groups. Berryman suggested that AES and SMPTE swop strategies as well as documents. Berryman said that it would be in the interest of the OCA Alliance to have contact with SMPTE, and hence that he might be a liaison. Treleaven provided further information related to the scope of SMPTE control, namely the control of any media device, and agreed to encapsulate this information for the use of the working group.

Liaison with Ethernet AVB: M. Mora, who leads this liaison, was not present. M. Lave provided input relating to 1722.1, and indicated that it was close to being ratified. Berryman provided information related to 1722a, in particular for the control of highly time sensitive applications, such as automotive applications. Gross indicated that there is further work being done in the 802.1 committee, in particular to reduce latency further, enhancing the stream reservation protocol, and synchronization. As an aside, Kevin spoke of work being done on updating the IEEE 1588 protocol. Continuing the aside, Berryman spoke of work being done to reduce cabling density.

Liaison with MPEG: J. Grant spoke briefly about MMT (MPEG Media Transport) and then spoke about the joint task force on networked media, a joint effort between SMPTE, VSF and EBU. User requirements are being gathered, and later there will be a public call for technology solutions, to be completed by IBC time. There is still work being done on future networks, and Grant gave a brief update on work being done.

Liaison with IEC 62379: Grant and P. Stevens reported. Work is being done on Part 3; Video, and Part 7 is being circulated by IEC as a Committee Draft for Vote (CDV).

New projects:

There was a proposal for an interoperability project between X210 and AES64.

Berryman proposed to have a 3-way approach to media networking - media transport protocol, control protocol, and a directory service mechanism.

Discovery is one way of populating a directory. Berryman proposed that work be done to define the interface between the media transport and the directory service, as well as between the control protocol and the directory service. It is immaterial what lies below the interface. Berryman requested that there be a project established to define this interface. The fundamental problem is name resolution. G. Linis was of the opinion that this is an application layer task, in particular the coordination of discovery, media transport and control. Berryman was concerned about interoperability if this is left to the application. Heinzmann spoke of the separate activities of populating and querying a directory. Berryman suggested that the AES could specify directory services. It was agreed to get discussion going on the reflector about this, and to determine a scope for the project prior to initialization.

New business:

There was no new business.

The next meeting will be scheduled in conjunction with the AES 135th Convention in New York, NY., US., 17 to 20 October 2013.

AES - Audio Engineering Society