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 New York, NY, USA at the Jacob Javits Convention Center, 2017-10-20
The meeting was convened remotely by Mark Yonge.
The agenda and the report of the previous meeting, held in Berlin 2017-05-20, were approved as written. The chair proposed to discuss AES-X236 first because this would drive the major topic of this meeting.
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.
Development Projects
AES-X236 - IEC 62942 liaison, IEC 62942 liaison, Broadcast Wave Format file
Scope: Adoption of AES31-2 as an IEC standard for broadcast wave format file, with addition of optional UBXT chunk to carry international character sets.
Status: A committee draft (CD) for IEC 62942 was circulated 2017-08-11 for comment; the comment period closes 2017-11-03. A copy of the CD was posted to SC-02-08 on 2017-09-02
This draft includes a new Annex K which provides a vehicle for human-readable metadata in multi-byte character sets that are not possible using ASCII characters. This 'Universal', or 'ubxt' chunk is designed to co-exist with the original 'bext' chunk, with safeguards to ensure predictable handling of machine-readable data in international interchange scenarios.
The necessity of multibyte characters to support international operations had been raised in this group as far back as 2003, but the need to ensure compatibility with the original 'bext' ASCII format seemed impossible to manage at that time. This technique using the 'ubxt' chunk seems valuable and is being considered for inclusion in a revision of AES31-2 (see below).
Open Projects
AES31-2-R Review of AES31-2-2012 Audio-file transfer and exchange - Part 2: File Format for Transferring Digital Audio Data Between Systems of Different Type and Manufacture
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.
Status: A review is required in 2017. On 2017-09-14, the chair proposed a revision to AES31-2 to include the option for an IEC 'ubxt' chunk.
In discussion, there was a general approval for the revision. Three substantive points arose:
• In Annex K.3, in the text immediately above Table K.1, a requirement should be added, "If machine-readable data in the 'ubxt' chunk is updated, machine-readable data in the 'bext' chunk shall also be updated in the same way."
• In Annex K.3, in the text immediately above Table K.1, A recommendation should be added, "When data is entered into the human-readable fields of the 'ubxt' chunk, the equivalent fields in the 'bext' chunk should provide an ASCII equivalent, if possible, or a null string.
• Guidance should be added to clarify end-of-line events in human-readable data fields. The convention used in the 'uCodingHistory' should be extended to the 'uDescription' field in table K.1. The same convention should also be extended to the 'Description' field in the 'bext' chunk in table 1.
It was felt that these points should be offered as comments to the IEC 62942 CD to keep these documents consistent.
AES69-R Review of AES69-2015: AES standard for file exchange - Spatial acoustic data file format
Scope: This document standardizes a file format to exchange space-related acoustic data in various forms. The format is designed to be scalable to match the available rendering process. The format is designed to be sufficiently flexible to include source materials from different databases.
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.
No action was requested or required.
Liaisons
No new liaison information
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 144th Convention, to be held 23 to 26 May 2018 in Milan, Italy.
