SC-02-12 meeting, Online, 2022-5

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 153th Convention, 2022-10-14.

The meeting was convened by chair Morten Lave.

The formal notice on patent policy was read.

The report of the previous meeting, held online, in connection with the 152th Convention, 2022-05-03, was approved as written.

The agenda was approved as posted.

In attendence were Morten Lave, Richard Cabot, Junichi Yoshio, Peter Stevens, Jim Meyer, Bruce Olson, Al Walker, Brian Vessa, Kent Terry, Kevin Gross, Andy Rosen, Andreas Hildebrand, Ievgen Kostiuke, Robert Wadge, Paul Treleaven, Hatano Wataru, Martin Renz, John Grant, Jeff Berryman, Richard Bugg

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

The revision is progressing well. The editor has done most of the initial work. The estimate Is that another 8-10h of meeting time is needed to complete the revision. There are 3 meetings scheduled in November. Work is being done on language improvements and on making the PIC’s less ambiguous and easier to fill out.

Due to the various holidays after the November meetings it is not likely that the draft will be completed this year. There is good momentum with 3-6 participants being active, and the required target is not until the end of 2023.

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

The revision of the core standard is moving well within the OCA group. It is expected that -1 and -2 will be ready for handover to SC02-12L in a week or so. The last part is expected to be handed to SC02-12L early in the new year. The completion of the revision is expected to be around March 2023. As originally planned the AES67/SMPTE and Milan adaptations are expected to be released in the months after this core revision. The completion of the JSON version of the standard (AES70-4) will depend on available resources and it is not clear when it will be ready.

The roadmap presentation can be found here, OCA-Roadmap-221014.pdf Access is limited to AES SC-02-12 Working Group members. If you are not a member and would like access you may join the group by contacting the Standards Manager.

General state of the AES70 standard:

The 2023 revision of the standard has a high maturity level, future additions are expected to be feature-set specific, like adding Video etc.

One other thing on the horizon has to be considered though and that is the advent of then NMOS group and a similar standard - NCA (NMOS Control Architecture). This standard has a strong resemblance to OCA. NCA is not very mature, but the framework is done, the functional repertoire is low. In some way it is a competing standard, and it will not serve the community well to have two competing standards. This might result in changes to converge the standards.

As a result of this a major revision might happen down the road.

It was asked if there is anything fundamental that would make it hard for the two to converge. It was stated that the fundamental models are similar enough to make them mergeable at this point.

This link provides an overview of the NCA documents and relevant links: NMOS-NCA-Document-Links-221014.pdf Access is limited to AES SC-02-12 Working Group members. If you are not a member and would like access you may join the group by contacting the Standards Manager.

AES-X242 Streaming audio metadata over IP

A little progress was made on the SMPTE side, they are close to getting to the stage this group is waiting for. Planning to setup a call late this year or January.

Still optimistic for a 2023 draft.

AES-X243 Audio applications of networks - Using AES70 for managing AES67 and SMPTE ST 2110-30 media stream connections

The draft in an advanced state. On track to release a month after AES70-1/2/3.

AES-X251 AES74 Conformance Survey

The survey has lost relevance as time has moved on. These minutes reflect a proposal is to cancel this project. If no objections have been received by the next meeting, the project will be canceled.

AES-X252 AES70 Milan Adaptation

Moving slowly within the OCA group. Expect to pass to X252 by end of year, lots of editorial effort with limited resources.


Liaison with MPEG (John Grant)

Nothing new to report.

Liaison with ETSI (John Grant)

Rumbles on slowly, the one to look at is DEC2020 which uses modern physical layers. Could be used for digital wireless microphones. Chips will not be available until next year, so nothing immediate to report here. It is non-IP low latency.

Signaling protocols are about to be published shortly. Will be downloadable for free.



Not much to report. IEC version of AES3 adding error correction codes – intended for wireless. Group just started.


Low latency Mac layer, PHY agnostic, works with WiFi, BT, etc. This is in an early stage.

Liaison with IEC62379-1 (Common control interface, orig. BBC project in 2004, ATM etc.) (Peter Stevens)

Originally part of ATM and was an attempt to do what AES70 is doing, never caught on.

Propose to drop tracking this here.

All the parts of this standard are probably going to be stabilized.

Liaison with ST 2059 (SMPTE) (Use of PTP for professional media sync.) (Paul Treleaven)

ST2059 work to modify PTP profile so it is in line with the latest IEEE1588 while backward compatible.

ST2110-30 is developing PIC’s for all core parts which includes the constrained AES67 compatibility. They are relying on the AES67 PIC’s but those are going to change.

All core parts of 2110 are ready to be published, mostly clarifications -10 includes a few new features.

Liaison with Avnu ProAV AVTP (Morten Lave)

Not much to report, the new test tool is being deployed, a high number of products are now certified under the Milan certification program.

Next Meeting

The next meeting will be scheduled in conjunction with the AES 154th Convention in early May 2023, it will be virtual. Standard meetings will likely be scheduled the week before the convention.

AES - Audio Engineering Society