SC-02-12 meeting, New York, 2011-10

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 in New York, 2011-10-22.

The meeting was convened by chair R. Foss.

The agenda and the report of the previous meeting, 2011-05-14, 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: N. Brock gave a presentation where he identified two common use cases for remote interaction, one for remote post production and one for distributed or telematic live sound. For both of these use cases he presented the audio configuration, personnel, and networking requirements at the various remote locations. He requested input from P. Stevens relating to broadcast requirements. K. Gross presented synchronization requirements. It was suggested that a task group be formed to complete the use cases, and this was assigned the task group number SC-02-12J. Brock has uploaded the current updated document to the working group document site.

Development Projects

AES-X075: Liaison with IEC TC100 for IEC 61883
Project Scope: Prepare recommendations and assist the work of IEC TC100SC-02-12 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 SC-02-12. Of particular importance is that the CDV of IEC 61883-6 Edition 3.0 has been completed. This document derives from the 1394TA A/M protocol 2.2 rev 1.0 and incorporates corrected editorial errors. The CDV will be submitted to the IEC after the DTCP revision is announced. This may be expected by the end of November 2011.

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

Discussion: There was no-one to provide a liaison report for this project. Some 1394TA information was provided within the AES-X075 report, relating to the A/M protocol.

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: After the London meeting, M. Yonge had performed extensive editing on the document, and raised a number of questions. These were addressed in a conference call between Yonge and Foss. Foss updated the document according to the resolutions in the conference call. Yonge will now proceed to review the updates, edit the English according to AES requirements, and provide a final draft for working group comment.

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 X170 specification, in particular: 1. The origins of the 7-level hierarchy. 2. The creation and processing of X170 messages. 3 Peer to peer grouping and master/slave grouping of device parameters. 4 Modifiers. 5. Deskitems.

Discussion: Once the X170A document is complete, Yonge will review the X170B document. The formatting requirements for such an informative document are 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 had been held the previous day. The meeting was well attended, and to guide the meeting, Gross had used the task group wiki that he had constructed. The wiki contains both the project requirements and technology components. There are 8 components, and the task group discussed 5 of these, these being the components that have been addressed by Gross. Gross will work on the remaining 3 components. There will be a conference call at the end of January. Gross will then write a draft, which will be ready by the next face-to-face meeting in Budapest.


Liaison with Ethernet AVB
M. Mora, who leads this liaison, was not present at the meeting. Gross provided an overview of AVB activities, and in particular current work areas. He indicated that the basic AVB standards are now ratified. There are efforts to improve the stream reservation protocol to provide for redundancy and multi-point to multipoint routing. There is also work being done to reduce latency. Automotive applications are driving work in AVB, and so there is a need to lower the latency for control data. There is active work in the 1722.1 working group - discovery, enumeration connection management and control. The group looked at many protocols and a new protocol has been developed for enumeration, basic control and connection management. The 1722 group is working on simplified formats and media clock distribution, transmitting media clock to transmitters so that all transmitters can transmit in sync.

Liaison with ESTA:
P. Nye, who leads this liaison was not present at the meeting, and there was no-one in a position to provide further information.

Liaison with MPEG:
J. Grant gave a presentation of MPEG activity relating to the working group. In particular he described a move within MPEG to provide a unified capability for the storage and streaming of audio. He showed a diagram of the proposed layered structure, and pointed to the many headers that would be incorporated in the resultant messages. There was a concern about the high levels of latency being proposed.

Future Networks
Grant also reported on work on 'Future Networks' in ITU-T SG13 and ISO/IEC JTC1/SC6, and discussed the motivations for going this route rather than current IP networks. SC6 is planning to begin standardisation of the new networks, which (unlike current IP networks) will provide the Quality of Service needed by live audio without requiring specialised management, in 2012.

Grant suggested a liaison with the SC6 'Future Networks' group

Liaison with IEC 62379:
Grant reported on the IEC 62379 meeting held two days previously. Both parts of part 5 had a CD ballot, and they will now be moved to CDV. He described part 4, which deals with control streams, and spoke about interest from MIDI in this part. He spoke about the capability that 62379 provides for streaming across multiple networks. Grant has updated a pdf containing his report onto the working group document site.

Grant's slides are in the working group document area with filename FN-liaison-report-JGrant.pdf; the presentation to the 130th Convention, which gives more detail of the current JTC1/SC6 work, is also in the document area, with filename liaisons-FN-Grant-110514.pdf.

New Projects:

The OCA (Open Control Alliance) contacted Mark Yonge, with the possibility of standardizing their protocol. Yonge informed them of the project initiation procedure.

New business:

N. Brock requested liaison with the SMPTE group. It was decided that the secretariat send a formal letter to SMPTE indicating that work was being done in similar areas and that it was desirable to establish a liaison. Gross indicated that time was of the essence and that the liaison should be established quickly.

The next meeting will be scheduled in conjunction with the AES 132nd Convention, in Budapest, Hungary, in April 2012.

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AES - Audio Engineering Society