SC-02-08 meeting, London, 2011-05

Report of the meeting of the SC-02-08 Working Group on audio file transfer and exchange of the SC-02 Subcommittee on Digital Audio, held in London, UK., 2011-05-13.

The meeting was convened by chair M. Yonge.

The agenda and the report of previous meeting, held in San Francisco, CA., US., 2010-11-05. were approved as written.

Open Projects

AES31-1-R: Review of AES31-1-2001 (r2006): AES standard for network and file transfer of audio - Audio-file transfer and exchange - Part 1: Disk format
Project scope: This document defines a disk format specification to maintain compatibility with as wide a user base as possible to facilitate audio-file transfer and exchange between differing systems. The document does not describe a complete disk format but provides enough information to choose a proprietary system that will maintain compatibility.

There have been no requests to update or revise this document. Because it is now due for it's five-year review, the meeting proposed to reaffirm this document.

AES31-2-R: Review of AES31-2-2006: Audio-file transfer and exchange - Part 2: File Format for Transferring Digital Audio Data Between Systems of Different Type and Manufacture
Project scope: This standard defines a file format for interchanging audio data between compliant equipment. It is primarily intended for audio applications in professional recording, production, post production, and archiving.

Because this document is due for it's five-year review, the meeting proposed to revise it to include two minor changes. The amendment 1, published in early 2009, will be incorporated to make a single, complete specification for BWF files. In addition, the new EBU eca-bwf work to embed loudness metadata in the 'bext' chunk will be considered for inclusion. Yonge will propose a draft revision.

AES31-3-R: Review of AES31-3-2008, AES standard for network and file transfer of audio - Audio-file transfer and exchange - Part 3: Simple project interchange. including maintenance of annex F.
Scope: This standard provides a convention for expressing edit data in text form in a manner that enables simple and accurate computer parsing while retaining human readability. It also describes a method for expressing time-code information in character notation. It supports common professional audio sampling frequencies, video frame rates, and film framing. This document addresses the core need of the AES31 series of standards in providing a simple but extensible system for passing audio material between systems.

No action was requested or required.

AES-21id-R: Review of AES-21id-2011, AES Information Document for audio-file transfer and exchange - Screen-less navigation for high-resolution audio on Blu-ray Disc
Project scope: This information document recommends a method for authoring a BD ROM to enable playback in consumer systems without a video screen, and to provide simple track selection from the remote control.

Following the successful publication of this document, no additional action was requested or required.


J. Yoshio recommended that AES31-2, when revised, be forwarded to IEC TC100 for consideration as an international standard.

New Projects

A. Holzinger raised the matter of channel assignments for tracks in a multi-track BWF file. He proposed a new scheme where metadata was built into the 'bext' chunk, or a similarly-purposed chunk, that carried a unique identifier for each track whose meaning could be derived from an external library of registered values. These identifiers would provide human-readable identification strings in multiple languages by providing multiple language options in the registry using Unicode. Holzinger argued that such a scheme could be implemented more easily in a time-critical applications such as playout devices where a more self-contained XML implementation of this metadata would tend to be unpredictable due to time variations in parsing more or less complex XML content. In discussion it was accepted that a block of unique-identifier values could be left undefined for sand-box experimentation and informal usage. Holzinger agreed to draft an outline draft for discussion.

New Business

There was no new business

The next meeting will be scheduled in conjunction with the AES 131st Convention to be held in New York, NY., US., 20 to 23 October 2011.

AES - Audio Engineering Society