SC-02-12 meeting report. Vienna 2007-05

Report of the meeting of 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 Vienna, Austria, 2007-05-07

The meeting was convened by chair J. Strawn

The agenda and the report of the previous meeting, held in San Francisco 2006-10-07, were accepted as written.

Development projects

AES-X075: IEC TC100 Liaison for IEC 61883
J. Yoshio reported. The IEC 61883-6 A/M protocol standard is being revised by the 1394 TA / AVGW.

The IEC 61883-8 committee draft on "Transmission of ITU-R BT.601 style Digital Video Data" is expected in June.

Regarding the IEC 60958 revision for audio data over IEEE 1394 there is a new audio format that takes into account higher sample frequencies and in the channel status component of IEC 60958. These formats will be applied to the 60958-conformant data format of IEC 61883-6. This includes higher sampling frequencies, and certain metadata (LFE info, loudness info, and so on). The IEC committee draft (CD) is expected in June.

With the introduction of big screen video - currently being catered for by Dolby ("True HD") and DTS ("HE") in Blue Ray and HDVD, and NHK's 22.2 channel surround formats - there is a need for a general multi-channel assignment both within HDMI and 61883-6. DTS carries up to 27 channels maximum; Dolby carries up to 20 channels. There is an attempt to unify these channel assignments. HDMI will use these channel assignment to supplement the current 8-channel HDMI assignments.

I have posted Yoshio's report to the document site as X75-yoshio_070610.pdf. The diagram of NHK's 22.2 format and the channel assignment tables are especially helpful.

AES-X101: Data Type, Properties, and Method Definitions for Audio Device Application Program Interfaces (API)
We inherited this from another group; we await secretariat reformatting; this is low on the secretariat's priority list.

AES-X126A : Profile for professional audio over 1394; "Application of IEC 61883-6 32-bit Generic Data"
This "Application of IEC 61883-6 32-bit Generic Data" document is not the OGT document. The document is a Proposed Working Group draft (PWD) at this stage. The secretariat is to format the document which will remain a PWD and posted to the SC-02-12 document site. The SC-02-12 chair will ask for objections to the document. After SC-02-12 reaches concensus (no objections) that the PWD matches its expectations, the document will become PCFC. This is a high-priority item for the Secretariat.

R. Foss asked about concensus and resolution of objections. Mark Yonge explained that Concensus is defined in IEC as the absence of sustained objection, and that if there is sustained objection to a draft then the document will need to be improved.

AES-X126B: Profile for professional audio over 1394; Specification of Open Generic Transport (OGT)
S. Harris, writer of the "L1_L2" document, is satisfied with its content; The document will continue to be available on the SC-02-12-G site but there is no plan to carry the document forward further.

Concering the OGT (Open Generic Transport) document, Foss' group in South Africa do not have the resources to write and ratify and implementation. They do not wish to carry this project further. This document will also continue reside on the document site. If someone wishes to continue this work, they are welcome to do so. If no one is found by the meeting scheduled for New York, 2007-10, it was proposed to close this project.

The same applies to the issue of OGT/AV-C compatibility.

AES-X132: Synchronisation of audio over IEEE 1394
T. Thaler, original author, is no longer available. We await the PWD as formatted by the secretariat.

AES-X137: Liaison with 1394 Trade Association (1394 TA)
Yoshio reported. A 1394TA meeting was held 2007-04-02 in Santa Clara, CA, USA

A. Yanowitz reported on transmission of MPEG 4 over IEEE 1394 (part of IEC 61883-4). He also reported on AES activities. D. Beadnell reported on ITU 601 and its relation to broadcast television. No action is currently being taken on this topic. There was also discussion about FMT and its meaning in that context. Finally there was a discusion about IEEE 1394.1 and its maintenance, especially regarding speeds over S400.

AES-X156: Use cases for IEEE 1394 in professional audio: Recording
The final documents for projects AES-X156 will be posted to the AES document site. The intention is to close these projects by the time of the meeting scheduled for New York, 2007-10.

AES-X157: Use cases for IEEE 1394 in professional audio: Live sound
The final documents for projects AES-X157 will be posted to the AES document site. The intention is to close these projects by the time of the meeting scheduled for New York, 2007-10.

AES-X158: Use cases for IEEE 1394 in professional audio: Audio installations
The final documents for projects AES-X158 will be posted to the AES document site. The intention is to close these projects by the time of the meeting scheduled for New York, 2007-10.


There were no other liaison issues.

New Projects

Integrated connection management and command and control protocol
Foss proposed a new project for an integrated connection management and command and control protocol for IEEE 1394, and presented a slide show detailing the project proposal. Foss indicated that the slide show will be made available on the SC-02-12 document site.

He mentioned that there had previously been an AES command and control related standard, namely AES24-1-1999. This standard was withdrawn a few years ago. Foss will communicate with J. Grant and determine if there might be some useful relationship between this new project and the work of IEC 62739, "Common control interface".

R. Chalmers asked if it might be appropriate to place the project within another group. Foss said that the implementation will be focused on 1394 so it might be good to put it under SC-02-12. Further discussion suggested that it might be possible in a later stage to move it to a different group.

Foss will complete a Project Initiation Request. SC-02 will assign the project to a working group, possibly SC-02-12.

New business

John Strawn resigned as chair of SC-02-12, citing his concern about his lack of technical background in this area. He will continue to participate via the reflector. Richard Foss, vice-chair of SC-02-12, has been proposed as chair of SC-02-12.

The next meeting will be scheduled in conjunction with the AES 123rd Convention in New York, NY., US, 2007-10.

AES - Audio Engineering Society