Report of the the meeting of the SC-02-01 Working Group on Digital Audio Measurement Techniques of the SC-02 Subcommittee on Digital Audio, held in New York, 2009-10-11
The meeting was convened by chair S. Harris.
The agenda and the report of the previous meeting, held in Munich 2009-05-09, was approved.
Open Projects
AES17-R, Review of AES17-1998 (r2004): AES standard method for digital audio equipment - Measurement of digital audio equipment
It was proposed to reaffirm the current document as soon as posible while work on the revision continues. Two new development projects have been created to support the next revision of AES17 and also an accompanying explanatory document; AES-X187A and AES-X187B (see below).
AES-6id-R Review of AES-6id-2006: AES information document for digital audio - Personal computer audio quality measurements
No action required or requested
AES-12id-R, Review of AES-12id-2006: AES information document for digital audio measurements - Jitter performance specifications
No action required or requested
Development Projects
AES-X102, Liaison with IEC TC100 PT 61606, Audio and audiovisual equipment - Digital audio parts - Basic measurement methods of audio characteristics
No activity required or requested
AES-X118, Liaison with ITU-R study group 6C
No activity required or requested
AES-X177, AV Sync, Lipsync
The BBC documents provided by A. Mason have been incorporated into a PTD for an AES report, posted 2009-08-26. No comments have been received. The meeting proposed that the secretariat should publish the report on behalf of the working group as soon as posible.
There is a SMPTE broadcast project for AV Synch; TV22l. Fingerprinting techniques can be used to confirm video and audio sync.
There is also a CEA document CEB20 AV Synch processing recommended practice about how to process presentation time stamps. This is for TV receiver manufacturers.
AES-X187A, Revision of AES17 AES standard method for digital audio equipment - Measurement of digital audio equipment , and AES-X187B, Companion ID to AES-X187A, AES standard method for digital audio equipment - Measurement of digital audio equipment
T. Kite has posted an early draft of AES-X187A to the SC-02-01 document site. Please send in your comments now.
Kite met with I. Dennis today to discuss some of the details. Kite will send around his list of top discussion points soon to the email reflector. Please respond.
T. Holman introduced a flaw in the current AES17 about 0 dBFS definition. 0 dBFS is defined using a single sine wave. The actual value of full scale in Matlab with different waveforms is 3 higher. This issue is only addressed with a note in AES17. Many current software meters are wrongly calibrated.
It was felt that the new updated document should have a clear definition of what 0 dBFS is supposed to be. Holman will send an email describing his input and preferably including some suggested text. Kite will work out how to include this idea into either the standard document, or the tutorial document, or both.
Liaisons
There were no liaison issues.
New Projects
No new projects were proposed
New business
There was no new business.
The next meeting will be scheduled in conjunction with the AES 128th Convention in London, UK, 2010-05.
