SC-02-12 meeting, Online, 2020-05

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 online in connection with the 148th Convention, 2020-05-28.

The meeting was convened by chair Morten Lave.

The formal notice on patent policy was read.

The report of the previous meeting, held in New York, USA, 2020-10, was approved as written.

The agenda was approved as posted

In attendence were Richard Cabot, Bruce Olson, Richard Foss, Richard Bugg, Kevin Gross, Eric Hoehn, Andreas Hildebrand, John Fletcher, Jonathan Zener, Paul Treleaven, Al Walker, Jeff Berryman, Jim Meyer, John Grant, Peter Stevens, Terry Holton, Kent Terry, Sean Chung, Anthony Kuzub, Brad McCoy, Junichi Yoshio, Stephen Scott, Gints Linis, David Andrews, Jonathan Zener

Projects assigned to this group but not mentioned here had no action requested or required - see for details.

Open Projects:

AES67-R - Review of AES67-2018 , AES standard for audio applications of networks - High-performance streaming audio-over-IP interoperability

Kevin Gross reported that the rate of revisions will be slowing down compared to the quick 2 to 3 year turnaround. The editor is currently working on a new revision expected to be ready in 2021.
The new revision will include some clarifications of PIC’s etc. and among other things:
- Source specific multicast
- IPV6 support
- Harmonization with SMPTE ST 2059 and ST 2110
A draft document is being produced.
Discussion around logo and promotional activities. A logo proposal will be coming shortly.

AES70-1-R Review of AES70-1-2018: AES standard for audio applications of networks - Open Control Architecture - Part 1: Framework

AES70-2-R Review of AES70-2-2018: AES standard for audio applications of networks - Open Control Architecture - Part 2: Class structure

AES70-3-R Review of AES70-3-2018: AES standard for audio applications of networks - Open Control Architecture - Part 3: Protocol for TCP/IP networks

Jeff Berryman reported that a new revision is in the works, this will require a change to all 3 parts of the standard. The target is 2021.

The current numbering scheme using the dash notation will be expanded such that the numbers up to and including -19 will be used for core specifications like the current -1, -2 and -3. A -4 is in the works for the support of JSON as the transport.

The numbers from 20 (or 21, not determined) are reserved for adaptations. Work is currently being done in SC-02-12L on the AES67 SMPTE ST 2110-30 connection management and likewise work is being done on the AVB Milan adaptation. The numbers will be allocated consecutively in the order the final drafts are being provided.

The ‘dash’ numbering of standards within a family is not new and is established AES practice.

The revision in the works for the core standards (-1, -2 and -3) are significant and among other things related to media, clocking, real-time performance of execution, logging and access control.

The group is currently participating in the NMOS study where OCA (AES70-2) is being proposed as a model.

Resumed discussions with the SC-04-04 regarding developing an AES70 profile for digital microphones. The profile would support the AES42 controls as a subset.

AES-X242 Streaming audio metadata over IP

Kent Terry reported:
The SC-02-12-R group has continued to hold roughly bi-weekly calls this year, with several regular participants. The group continues work on its primary goal of having a final draft of AES-X242 completed in 2020.

A major item of discussion in SC-02-12-R has been on harmonization with the proposed ST 2110-41 "Fast Metadata" standard under development in SMPTE. The SMPTE SVIP DG developing ST 2110-41 has produced a first draft, and two additional revisions, of ST 2110-41 and SC-02-12-R has begun a revision of AES-X242 that is intended to be harmonized with ST 2110-41. In practical terms this will require AES-X242 to reference ST 2110-41. SC-02-12-R has shared additional information on AES-X242 with SMPTE, and as AES rapporteur the SC-02-12-R chair has provided comments and feedback on the ST 2110-41 draft. The group remains hopeful that the goal of harmonization can be achieved however the ballot progress on ST 2110-41 may delay the final draft of AES-X242.

In addition to work on the AES-X242 draft, SC-02-12-R continues to collect information on use cases and planning for validation testing with key use cases. A call for input on use cases and user requirements was published in late 2019, but limited feedback was received.

AES-X243 Using AES70 connection management for AES67

Goal updated to be a standard, goal 2020.
It was noted that the title and scope should be changed to reflect both AES67 and SMPTE ST 2110-30.

AES-X251 AES74 Conformance Survey

The AES74 standard specifies the requirements for a directory service. The AES-X251 is a project to establish which current directory services can conform to the AES74 requirements. Several candidates have been identified as high priority for conformance check. An AES74 Conformance Questionnaire is currently in the drafting phase.


Liaison with MPEG (John Grant)
Nothing new to report.

Liaison with mobile (John Grant)
Reporting on ETSY: NGP (Next Generation Protocols) now finished. As the group concluded that IP was not the way to go, a new group called Non IP Networking has been formed.

There are currently 19 member organizations, writing 3 documents.

The first one setting up the problem, the second one talking about how to do it over wireless (reliable delivery, low latency etc.) , and the last one is the network model setting the ‘mathematical axioms’ so to speak.

The goal is to be able publish these 3 documents before the end of this year and then start prototyping appropriate technology and test it out, starting by the end of the year.

Would welcome participation from anyone who is interested.

Liaison with AMWA (Anthony Kuzub)
Working on NMOS, involved in study creating profiles for equipment. Aim to find a generic way to describe the behavior of a device as it behaves within a certain family or class. This is the very same effort referenced above under AES70 in relation to NMOS.

Liaison with IEC62379-1 (Common control interface, orig. BBC project in 2004, ATM etc.) (Peter Stevens)
There may well be some amendments but then it will likely be stored away.

ST 2059 (Use of PTP for professional media sync.) (Paul Treleaven)
The use of the two parts -1 and -2 are getting close to being published as a revision, it has taken a long time. The good news is that it is close to being published. However, the base standard IEEE 1588 has undergone some major changes which will be published as version 2.1. The next big job for ST 2059 will be to incorporate those changes.

Liaison with Avnu ProAV AVTP (Morten Lave)
The Milan standard is published, it is an interoperability standard for pro-audio over AVB.
A test specification is also released.
Work is currently being done on the next version of the test specification.

Next Meeting
The next meeting will be scheduled in conjunction with the AES 149th Convention, to be held online in October 2020

AES - Audio Engineering Society