Report of the meeting of the SC-02-02 working group on digital audio interfaces, of the subcommittee on digital audio, held in New York, NY., US., 2015-10-29.
The meeting was convened by chair J. Grant, participating remotely from the UK.
The agenda, and the report of the previous meeting, held in Warsaw, 2015-05-07, were approved as written.
Projects assigned to this group but not mentioned here had no action requested or required - see www.aes.org/standards/meetings/project-status.cfm for details.
Open projects:
AES3-4-R: Review of AES3-4-2009 (r2014), AES standard for digital audio - Digital input-output interfacing - Serial transmission format for two-channel linearly represented digital audio data - Part 4: Physical and electrical
and AES-2id-R: Review of AES-2id-2006 (r2012): AES information document for digital audio engineering - Guidelines for the use of the AES3 interface
J. Paul reported that the new draft has been delayed because neither he nor M Danielson had been able to devote enough time to it. It will be backwards compatible with the current version, so that equipment designed to the current version will still be conformant. Advice on equalisation (currently in C.3.1 of AES-2id) will be omitted as it is no longer used. P. Treleaven reminded the meeting that a number of other points which should be included are documented in the report of the Warsaw meeting.
AES10-R: Review of AES10-2008: AES Recommended Practice for Digital Audio Engineering - Serial Multichannel Audio Digital Interface (MADI)
and AES-10id-R Review of AES-10id-2005 (r2011): AES information document for digital audio engineering - Engineering guidelines for the multichannel audio digital interface (MADI) AES10
S. Flock reminded the meeting of the issues concerning the use of SDI interface ICs, which are specified for a higher signalling voltage. M. Brunke offered to draft a new version.
AES50-R, Review of AES50-2011, AES standard for digital audio engineering - High-resolution multi-channel audio interconnection (HRMAI)
The chair noted that AES50 and its companion document AES-R6 are due for review in 2016, and as the system seems unlikely to be developed further they will be candidates for stabilisation. This should be discussed at the next meeting, in Paris.
AES47-R, Review of AES47-2006 (r2011): AES standard for digital audio - Digital input-output interfacing - Transmission of digital audio over asynchronous transfer mode (ATM) networks
The chair noted that AES47 and its companion document AES-R4 are due for review in 2016, and as the system seems unlikely to be developed further they will be candidates for stabilisation. This should be discussed at the next meeting, in Paris.
AES51-R, Review of AES51-2006 (r2011): AES standard for digital audio - Digital input-output interfacing - Transmission of ATM cells over Ethernet physical layer
This could be a candidate for stabilisation as it relates to a legacy networking technology. Parts of them may be applicable to new networking technologies, in which case there will need to be a decision whether to update them or extract the relevant parts into new standards. Again, should be discussed at the next meeting, in Paris.
AES53-R, Review of AES52-2006 (r2011), AES standard for digital audio engineering - Insertion of unique identifiers into the AES3 transport stream
This also relates to a legacy networking technology, however to be applied to new technology it would need to be updated because it makes reference to the epoch provisionally defined in a draft SMPTE document, and the epoch in the subsequently-published SMPTE standard is different.
AES-R8-R, Review of AES8-2015: AES standards project report - Synchronisation of digital audio over wide areas
The revised version of this document has now been published.
Development projects:
AES-X182: AES/Ethernet Simple Open Protocol
Secretariat reported that U Zanghieri no longer works for the company that proposed this project, and no further progress is expected. The project is to be retired.
AES-X196: Use of AES3 with high sampling rates to carry multi-channel audio
There has been no input from the organisation that originally requested this project, so it is to be retired. P Treleaven noted that some of the IEC proposals for surround sound in IEC 60958 may be similar.
AES-X213: MADI over twisted-pair cabling
The draft which is in the WG document area as x213-150506-ptd-mb.pdf has now achieved consensus in the TG, so is ready to proceed to Proposed Working-group Draft (PWD).
AES-X221: IEC 60958-4 Ed.3 revision
The drafts have been approved for publication by IEC, so the project has been completed and will be retired.
Liaisons:
J. Yoshio reported that revision of IEC 60958 Parts 1 and 3 is now under way, and there is also to be a new Part 5 to cover transmission of 22.2 surround sound over HDMI.
The chair reported that the mobile telecoms industry has begun development of a new generation which is called IMT-2020 (IMT = International Mobile Telecoms) in ITU and 5G (to follow on from 3G and 4G) in other groups. One aim is for latency close to 1 ms end-to-end within a metropolitan area, to support "Tactile Internet" applications, and this would clearly be good for audio as well. ITU-T has already begun work on the wire-line aspects, and ETSI is expected to start early in the new year.
New projects
No new projects were proposed.
New business
No new business was proposed.
The next meeting will be scheduled in conjunction with the AES 140th Convention in Paris, 2016-06.
