SC-02-12 meeting report. New York, 2007-10

Report of the meeting of the SC-02-12 Working Group on Audio Applications Using the High Performance Serial Bus (IEEE 1394) of the SC-02 Subcommittee on Digital Audio, held in New York, USA, 2007-10-07

The meeting was convened by chair R. Foss.

Suggestions for amendments to the published agenda, previously circulated on the reflector by Foss, were agreed upon by the participants.

The report of the previous meeting, 2007-05-07, was accepted as written.

Development projects

AES-X075: IEC TC100 Liaison 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.

Assigned to: SC-02-12, Initiated: 1998,
Intent: Liaison, Target: Continuing
Current goal: Status report, Goal date: Continuing

Junichi Yoshio reported:

Currently these is no activity for IEC 61883-2.

After A/M protocol is revised in 1394TA, it will be proposed to IEC to revise IEC 61883-6.

The NP (New Work Item Proposal) of General Channel Assignment was proposed. This will be quoted by the A/M protocol. The NP arises from industry needs, in particular: Dolby and DTS need more channels than the current application. NHK needs 22.2 channels for the future broadcasting. There is no general multi-channel assignment with enough channel numbers for audio interfaces - this should be standardized. This general multi-channel assignment can be applied to the A/M protocol and other interfaces.

A document containing an outline of the channel assignment proposal, "X75-yoshio-ChAssign-071007", has been posted to the SC-02-12 document site.

AES-X101: Data Type, Properties, and Method Definitions for Audio Device Application Program Interfaces (API)
Project scope:
Define and publish recommended data types, properties, and methods for use in the control of common audio devices.

Assigned to: SC-02-12, Initiated: 1999-12
Intent: Report, Target: 2006
Current goal: PWD
Discussion: The secretary indicated that this document was considered comparatively low priority, and required considerable formatting, amounting to about a week of work. Richard Foss agreed to review the document and report to Mark Yonge whether this document was of value to the working group.

AES-X126A : Profile for professional audio over 1394; "Application of IEC 61883-6 32-bit Generic Data"
Project scope:
to describe unique requirements for professional audio carried over 1394.

Assigned to: SC-02-12, Initiated: 2001-05
Intent: Standard, Target: 2007
Current goal: PCFC, Goal date: 2008-04
The secretariat is to format the document which will remain a PWD and posted to the Sc-02-12 document site.

AES-X126B: Profile for professional audio over 1394; Specification of Open Generic Transport (OGT)

Assigned to: SC-02-12-G, Initiated: 2001
Intent: Standard, Target: 2007
Current goal: PTD, Goal date: 2007-10
The task group document will remain in its current form on the document site until such time as someone shows an interest in moving it forward to a standard. SC-02-12-G, whose sole task was the creation of a PWD from this PTD, will also be terminated.

AES-X132: Synchronisation of audio over IEEE 1394
Project scope:
to specify methods of audio clocking and sampling-frequency synchronisation in a professional audio network based on the IEEE 1394 high performance serial bus. Include techniques to ensure devices function correctly in a network which includes IEEE1394.1 compliant bridges

Assigned to: SC-02-12-G, Initiated: 2005-10
Intent: Standard, Target: 2007
Current goal: Sec-formatted PWD, Goal date: 2008-05
Discussion: Steve Harris commented that conceptual work was completed on this document, and that it is worthwhile to complete the formatting work. If 1394.1 bridges do become available in the future, then this document will be a useful working document.

AES-X156: Use cases for IEEE 1394 in professional audio: Recording
AES-X157: Use cases for IEEE 1394 in professional audio: Live sound
AES-X158: Use cases for IEEE 1394 in professional audio: Audio installations

These three projects and their associated task groups have completed thewir tasks and were closed. The project number AES-X156 was retained, and the description of the project changed to:
"Use cases for networks in professional audio"
The three documents produced from the task groups of the three projects - AES-X156, AES-X157, and AES-X158 - will be merged and formatted by the secretariat to produce a single document (PTD) for review by the SC-02-12 working group with the intention of creating a general report on "use cases for networks in professional audio applications". The project will now be handled directly by the SC-02-12 working group.

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

Assigned to: SC-02-12, Initiated: tba
Intent: Liaison, Target: Continuing
Current goal: Status report, Goal date: Continuing

Junichi Yoshio reported. The third-quarter meeting of the 1394TA was held on 12 July in Oxford, England. The agenda was;

  • A/M protocol update (Junichi Yoshio / Pioneer)
  • Update on AV/C Enhancements for Music Subunit Devices (Andy Yanowitz / Apple)
  • US STB Testing (Richard Mourn / Quantum Parametrics)

The A/M protocol update was a status report of study reported by the chair Mr. Sawada, the amendment will be proposed at the 1st-quarter meeting of 2008.

The amendment to A/M protocol will include the following items;

  • General Channel Assignment
  • Loudness Data
  • LFE data

Categories for BluRay Disc (BD) and HD DVD are still under study now.

M. Mora provided further information on AV/C enhancements for Music Subunit devices. In particular he indicated the move towards providing true networking of audio devices and not just peer to peer connections between device and computer. He showed how features in the Audio Subunit were being incorporated into the Music Subunit, and also focused on mechanisms for latency control. Mora will be putting his presentation onto the SC-02-12 document site as well as some pertinent draft documents.


Internet Engineering Task Force (IETF)
Mora indicated that it would be good to liaise with the IETF with regard to the newly proposed project AES-X170. Yonge requested a liaison contact, and Mora said he would investigate.

IEEE Ethernet AVB
Foss suggested that this working group liaise with the IEEE Ethernet AVB working group which is planning work that appears to overlap the professional 1394 work in SC-02-12. Mora is currently involved with the Ethernet AVB working groups, and agreed to perform this liaison task. The secretariat will initiate a liaison with the Ethernet AVB project.

New projects

Integrated Connection Management and Command and Control Protocol
Yonge indicated that a new project, AES-X170 "Integrated Connection Management and Command and Control Protocol", was being initiated. This project had been informally presented by Foss and R. Gurdan in the Vienna meeting. A more formal proposal was subsequently submitted and there was a more detailed presentation of the project in the SC-02-12-G task-group meeting.

It was decided in the meeting to create a new task group specifically for this new project, and to call for participation in the task group.

New business

Foss proposed that working group SC-02-12 extend its scope to include Ethernet AVB, particularly since the real time media streaming goals of Ethernet AVB are similar to those of IEEE 1394. This was agreed upon within the meeting, and there was further agreement that there be a proposal to change the name of this working group to:

"SC-02-12: Working Group on Audio Applications of Networks"
It was felt that this name appropriately expresses the expanded scope of the working group.

The next meeting will be scheduled in conjunction with the AES 124th Convention in Amsterdam, Netherlands, 2008-05.

AES - Audio Engineering Society