Report of the meeting of the SC-02-01 Working Group on Digital Audio Measurement Techniques of the SC-02 Subcommittee on Digital Audio, held in San Francisco, CA., US., 2006-10-06

The meeting was convened by chair S. Harris

The agenda and the report of the previous meeting, 2006-05-21, were accepted as written.

Open Projects

AES-R7, Standards project report - Considerations for accurate peak metering of digital audio signals
This report has now been published. No comments at the meeting other than to thank I. Dennis for writing the document.

AES-6id, AES information document for digital audio - Personal computer audio quality measurements
The draft is complete and no futher comments have been received or were raised at this meeting. Proposed to advance the document to PCFC as soon as practicable.

AES17-R, AES standard method for digital audio equipment - Measurement of digital audio equipment
T.Kite and Dennis are in the process of revising this document, adding a section about multi-tone and Fast Fourier Transform (FFT) test methods. The revision will make individual tests less dependent on specific equipment, so the procedures can be implemented in a range of equipment.

A major rewrite is due from Kite, who will send a draft out for review before the end of December 2006. If anyone would like to contribute to the AES17 revision process, please send an email to the reflector (or see the page on participation).

Development Projects

AES-X102, Liaison With IEC PT 61606
Revised date for the CDV for IEC 61606-3 is end of 2006. Dennis must submit his contribution before the end of October 2006.

AES-X118 ITU-R study group 6 liaison
Following the development of the proposed ITU-R document BS.1770, there was discussion of defining suitable units for the loudness measurements this describes.

Contributions are requested regarding the time period of the loudness measurements; short term measurement versus a longer term measurement. Comments sent to the SC-02-01 reflector will be passed to the ITU-R raporteur, C. Todd.

Noted that the next ITU-R study group 6 meeting is in Geneva, 2007-05.

AES-X141, Accurate measurement and indication of peak signal levels to avoid overload of digital media
The work of this project is complete with the publication of AES-R7. It is proposed that this project be retired.

AES-X151, Specifying jitter performance
The draft is substantially complete. Harris and Yonge will create a foreword. Yonge will update rms and Hz styles.

Proposed to offer this document for comment as AES-11id-xxxx [SEC: actually allocated as AES-12id]

New Projects

No new projects were proposed.

New business

There was a discussion about lip-sync (differential delays between sound and picture) being a serious issue and various methods of measuring this. It was not clear if any activity is needed. If there are any contributions about lip-sync issues, please send to the reflector.

The next meeting will be scheduled in conjunction with the AES 122nd Convention in Vienna, Austria, 2007-05.