October 2002 meeting of SC-02-05

[page updated 2002-12-21]

Report of the SC-02-05 Working Group on Synchronization of the SC-02 Subcommittee on Digital Audio meeting, held in conjunction with the AES 113th Convention in Los Angeles, CA, US, 2002-10-03

Chair R. Caine convened the meeting.

The agenda was accepted with three additions:

  1. provision to adjourn for Task Group discussions;
  2. liaison after item 4;
  3. receive Task Group reports.

The report of the previous meeting held in conjunction with the AES 112th Convention in Munich, Germany, was accepted as written.

Open projects.

AES5-R Review of AES5-1998 AES recommended practice for professional digital audio - Preferred sampling frequencies for applications employing pulse-code modulation
An e-mail of 2002-09-18 from the chair to the standards manager requesting a formatted PWD of the revised document was discussed at length. Two items on this e-mail have been discussed on the reflector. Clause 5.2.5 is proposed to be added, saying: "Techniques have come into common use since the above frequencies were defined which use very high sampling rates typically more than 100 times higher than 48 kHz. Where such sampling frequencies appear at an interface it is preferred that multiples containing only the factor of two of sampling frequencies referred to in AES5 be used."

Caine will pass the proposed wording of clause 5.2.5 to secretariat for inclusion in a PWD to be ready by mid-November 2002.

Revision is due 2003.

AES11-R Review of AES11-1997 AES recommended practice for digital audio engineering - Synchronization of digital audio equipment in studio operations
Two e-mails from the chair to the standards manger were discussed at length. The first is a list of corrections and the second an additional item. The secretariat will produce a revised PWD by mid-November 2002. This will be notified to the reflector as a matter of course.

Revision is due 2002.

AES-X121 Synchronization of Digital Audio over Wide Areas
No report was available from SC-02-05-D.

The date for a PTD is moved to the end of December 2002.

Time and Date in AES11 DARS
No project number is allocated. Caine will raise a project initiation form. An adjournment to convene a meeting of the task group was considered unnecessary at this stage. Now that Project X111 is writing a document to map a Unique Material IDentifier (UMID) into AES3, a draft may be made consistent with this in AES11 DARS

PTD by March 2003.


The Society of Motion Picture and Television Engineers (SMPTE)
An informal report by M. Poimboeuf described the work of the Digital Cinema group DC28. Poimboeuf is a member of subgroup DC28.2, mastering format, which has formed an ad hoc group on synchronization. They have recommended to DC28 that digital reference should be based on a 48-kHz audio reference with no variation for pull-up and pull-down. This is because the video has a range of line and frame rates and sprocket variations.

This liaison is active, but no report was available.

New projects

No new projects were introduced or requested.

New business

There was no new business.

The next meeting is scheduled to take place in conjunction with the AES 114th Convention in Amsterdam, The Netherlands.

AES - Audio Engineering Society