SC-02-12 meeting, Budapest, 2012-04

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 Budapest, 2012-04-28.

The meeting was convened by chair R. Foss.

The agenda and the report of the previous meeting, 2011-10-22, were accepted as written.

Open Projects

AES-R10: AES standards project report - Use cases for networks in professional audio
Project Scope: To identify and clarify use cases for networks in professional audio applications for Recording, Live sound, and Installations

Discussion: The task group with the number SC-02-12-J has been established to enhance this report. N. Brock reported that some preliminary work had been done within the task group - use cases for wide area networks have been included in the document, and K. Gross has contributed text regarding synchronization. The task group is aware of work done within the EBU relating to use cases for broadcast, and intends to incorporate these use cases. Brock will be doing further work on the document, in particular to make it more readable, and will make a link to the document available to members of TC-NAS. The goal is to have approval for a version of the document by the next meeting in October.

Development Projects

AES-X075: Liaison with IEC TC100 for IEC 61883
Project Scope: Prepare recommendations and assist the work of IEC TC100 regarding the development and maintenance of relevant parts of IEC 61883. Any assigned task group shall report project progress to SC-02-12 and shall ask SC-02-12 for its advice on content. Administrative review of the project shall follow AESSC rules.

Discussion: J. Yoshio provided a liaison report that described work done on TC100 specifications related to this group. The committee draft for vote (CDV) of IEC 61883-6 Edition 3.0 has been submitted. Work has been done on IEC 61883-8, that specifies transmission of video data, and there is a new version of DTCP, DTCP plus, that is expected to be available in May. TC100 is considering a further revision that will deal with car applications, and there is an attempt within TC100 to establish a liaison with IEEE. There was some discussion about the importance of this, given that IEEE 1722 depends on IEC 61883 standards.

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

Discussion: In the absence of M. Lave, who is the AES liaison with the 1394TA, Yoshio gave an informal report. He indicated that version 2.2 of the A/M protocol had been completed, and that there had been a 1394 TA teleconference, which he did not attend.

AES-X170A: Integrated Control, Monitoring and Connection Management for Digital Audio and other Media Networks
Project Scope: The objective of this project is to create and standardize: 1. A set of structured Internet Protocol-based messages that can be used to control single parameters or groups of parameters, and to monitor these parameters. The parameters are associated either with typical signal processing functionality within audio devices, synchronization between such devices, or connections between such devices. 2. A mechanism for grouping of device parameters, and messages required to implement such grouping. 3. A mechanism for the control of latency within networks of audio devices, and a specification of the messages and parameters required for the control of such latency. 4. Parameter modifiers, and the messages required to create and configure such modifiers. 5. Security levels, and the messages required to set and get such levels.

Discussion: M. Yonge reported that there had been a series of edits to the document following the meeting at the New York AES, and further telephonic meetings with Foss. The edits had included such things as consistent labelling of parameters, and making the text more rigorous. Yonge indicated that a draft, now 86 pages in length, would be made available to the group for comment shortly after the meeting, and was positive about its current state.

There was some discussion about other control protocols, in particular the layer 2 AVDECC (IEEE 1722.1) protocol, and the layer 3 OCA protocol, and how to enable interoperability between these various protocols. Foss described a proxy approach used to enable AES-X170 and AVDECC interoperability.

AES-X170B: AES standards report - supplementary information on AES-X170A, ICMCM
Project Scope: The objective of this information document is to present additional tutorial information pertaining to particular aspects of the AES-X170 specification, in particular: 1. The origins of the 7-level hierarchy. 2. The creation and processing of AES-X170 messages. 3 Peer to peer grouping and master/slave grouping of device parameters. 4 Modifiers. 5. Deskitems.

Discussion: Once the AES-X170A document is complete, Mark Yonge will be reviewing the AES-X170B document. The formatting requirements for such an informative document are expected to be comparatively simple.

AES-X192 High-performance streaming audio-over-IP interoperability
Project Scope: The goal is to standardize the format for audio data within IP packets. Currently there are a number of ways of transmitting uncompressed audio over IP. There are even a number of ways of transmitting audio using RTP.

Discussion: K. Gross, the task group leader, presented a report of the proceedings of the task group meeting that was held earlier in the day. The main intent of the meeting was to deal with a number of comments relating to version 0.3 of the draft standard. There have been 59 comments, and 10 of these comments have been dealt with so far. Gross estimated that a further 18 hours would be required to resolve these comments, and a further 3 teleconferences have been scheduled for this purpose. The current goal is to have task group approval of the draft before AES San Francisco, and at this time the draft will be passed onto the working group for approval.


Liaison with Ethernet AVB: - M. Mora, who leads this liaison, was not present at the meeting. There was some discussion regarding the progress of the IEEE 1722.1 (AVDECC) specification, which is currently at version 19. Foss indicated that he would pass on any liaison information from Mora to the working group.

Liaison with MPEG: J. Grant gave a presentation of MPEG activity relating to the working group. Grant referred to the MPEG MMT (MPEG Media Transport) group, but did not know of any progress within the group. The original desire was to have a protocol that allowed for networked real time media and file transmission. He indicated that the latency requirements are not stringent. Grant also updated the working group on the status of the 'Future Networks' initiative.

Liaison with IEC 62379: P. Stevens reported on the status of IEC 62379, and indicated that a PT62379 meeting would be held on the following day. No further work has been done on the audio component of 62379, but would require maintenance at a later point in time. A Final Draft International Standard (FDIS) of the audio component (part 2) is available on the document site. Grant directed the working group to the IEC 62379 project web site

New projects:

There were no further projects.

New business:

Grant referred to the networking track that was discussed at the TC-NAS meeting and that was relevant to the next AES Convention in San Francisco, an initiative that would be driven by Brock.

The next meeting will be scheduled in conjunction with the AES 133rd Convention, in San Francisco, USA, in October 2012.

AES - Audio Engineering Society