Report of the meeting of the SC-02-02 working group on digital audio interfaces, held in Dublin, Ireland, 2019-03-22.
The meeting was convened remotely by chair J. Grant.
Present were Paul Treleaven, Ian Dennis, Hedd Morfett-Jones, Richard Cabot, Bruce Olson, Mike Law, Gen Ichimura, Isao Anazawa, Junichi Yoshio, Mark Yonge *, Anthony Kuzub *, John Grant* (* denotes by electronic link)
The formal notice on patent policy was read.
The agenda, and the report of the previous meeting, held in New York, NY, 2018-10-19, were approved as written.
AES3-n-R: Review of AES3-n-2009 (r2014), AES standard for digital audio - Digital input-output interfacing - Serial transmission format for two-channel linearly represented digital audio data - Parts 1 - 4
AES10-R: Review of AES10-2008 (r2014): AES Recommended Practice for Digital Audio Engineering - Serial Multichannel Audio Digital Interface (MADI)
AES11-R: Review of AES11-2009 (r2014): AES Recommended Practice for Digital Audio Engineering - Synchronization of digital audio equipment in studio operations
All four parts of AES3 are due for revision or reaffirmation this year, as are AES10 and AES11. No amendments have been proposed, so they should be reaffirmed.
AES5-R: Review of AES5-2008 (r2013): AES recommended practice for professional digital audio - Preferred sampling frequencies for applications employing pulse-code modulation
The new edition, in which 32 kHz and "pull-up" and "pull-down" rates were moved to section 5.4 and material relating to use with video signals was moved to an annex, has now been published. There had been proposals for a further revision, or an Information Document, to add more detail relating to use with video, but no text has been forthcoming.
Liaisons:
G Ichimura presented liaisons regarding IEC 60958-5 and 61937-1 which can be found on the SC-02-02 document site along with two IEC documents to which they refer. IEC 60958-5 supports up to 64 channels, and includes channel arrangement specifications. The new edition of IEC 61937-1 will support a "mixed mode" which can carry both compressed and uncompressed data; one application for this would be to carry program material that was received in a compressed format together with locally-generated audio without needing to compress the latter. The scheme illustrated in the liaison statement, which requires buffering of 192 samples of audio, is unlikely to be used.
New projects
The meeting discussed a proposal from A Kuzub for a standard to assign signals to the eight channels that would be available when carrying AES3 over the four pairs specified in AES72 (formerly AES-X246), for various use cases.
A proposal from M Law to add transmission over multimode fibre to AES3-4 was also discussed.
In each case a Project Initiation Form needs to be submitted through the usual channels.
New business
No new business was raised.
The meeting closed at 11:05.
The next meeting will be scheduled in conjunction with the AES 147th Convention, to be held October 2019 in New York, NY US.
