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 New York on 2011-10-22
The meeting was convened by chair S. Harris.
The agenda and the report of previous meeting, held in London on 2011-05-15, were approved as written.
Open Projects
AES-6id-R Review of AES-6id-2006: AES information document for digital audio - Personal computer audio quality measurements
AES-6id was reaffirmed in October 2011. No further action was requested or required.
AES-12id-R Review of AES-12id-2006: AES information document for digital audio measurements - Jitter performance specifications
AES-12id was reaffirmed in October 2011. No further action was requested or required.
AES-R11-R Review of AES-R11-2009, AES standards project report - Methods for the measurement of audio video synchronization error
No action requested or required.
Development Projects
AES-X102 Liaison with IEC TC100 PT 61606, Audio and audiovisual equipment - Digital audio parts - Basic measurement methods of audio characteristics
No action was requested or required.
AES-X118 Liaison with ITU-R study group 6C
A. Mason made some comments:
ITU-R BS.1770 has been revised to -2 revision, and now includes a gating method. There are plans for BS.1771 to be updated with new time constants, and some further work is happening. Mason can provide more information if requested.
True Peak meter discussions are also ongoing, related to a specific oversampling regime.
AES-X187A Revision of AES17 AES standard method for digital audio equipment - Measurement of digital audio equipment
T. Kite posted the latest draft document to the SC-02-01 document site yesterday, 2011-10-21. Unfortunately, Kite was not able to join the meeting to discuss the document. Harris requested that working-group members read through the document and send feedback comments to the reflector.
AES-X187B Companion ID to AES-X187A, AES standard method for digital audio equipment - Measurement of digital audio equipment
Kite has published a rough outline and is planning to continue to progress this document.
Liaisons
No new liasons
New Projects
No new projects
New Business
Discussion from C. Lacinak, Audio Visual Preservation Solutions. Federal Agencies Digitisation Guidelines, (FADGI) is working on audio archiving nad some techical issues have arisen:
Topic 1: A/D converter performance testing project.
Lacinak would like to propose a project to develop an AES standard for A/D converter specifications for archival purposes. We discussed how a test device might check that an A/D converter met the performance requirements.
I. Dennis and R. Cabot have made some inputs to A/D converter testing specification document. Also Cabot has been making some tests on specific converters.
Planning to publish some results soon on digitisationguidelines.gov web site.
Topic 2: Test that identifies interstitial errors
Interstitial errors happen when samples from an input stream are not recorded to disk. This is caused when the resources of the operating system are temporarily overloaded by other tasks. Deferred procedure calls can cause breaks in the audio.
Some proposed test and measurement solutions include comparison against a device which does not use an operating system.
The meeting discussed whether this was a real problem, and to what extent is this a common issue. A survey has been made and the results are expected to be published soon.
There was a discussion about using the local sample address field in AES3 Channel Status to ensure signal integrity.
Lacinak is researching methods of checking for real time hard disk write errors.
The next meeting will be held at the AES 132nd convention in Budapest in April 2012.
