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 London, UK., 2010-05-24
The meeting was convened by chair S. Harris.
The agenda and the report of the previous meeting, held in New York, 2009-10-11, was approved.
For projects assigned to the working group but not listed below, no action was requested or required.
Open Projects
AES 17-R Measurement of digital audio equipment
The current version has been reaffirmed. A new version is being created, see later projects: AES-X187A, and AES-X187B
Development Projects
AES-X102 Liaison with IEC PT61606
Some history. IEC 61606, "Audio and audiovisual equipment - Digital audio parts - Basic measurements methods of audio characteristics" has four parts:
Part 1 - General
Part 2 - Consumer Use
Part 3 - Professional Use. This group (Ian in particular) strongly
influenced this.
Part 4 - Personal Computer
IEC 61606 Part 4 (Personal Computer) is now open for comment. Ian felt that this group should get involved, but that he was not prepared to lead this. Perhaps W. Jones, who was heavily involved in updating AES6-id, might be interested in getting involved in providing feedback on this Part 4.
If anyone is interested in getting involved in influencing Part 4, please send an email to this group. [Or to the AES Standards secretariat].
AES-X118 Liaison with ITU
BS.1770 Loudness measurement
A recent ITU-R meeting, April 2010, was cancelled because of the effect of Icelandic volcanic ash on European travel arrangements. intent is to make some progress by correspondence before October meeting.
This document is being updating to include a gating function so that extended periods of silence do not unduly affect loudness measurements of the active signal. - awaiting discussion of test results of candidate functions.
There was a discussion about target level for TV audio. A new recommendation has been published as ITU-R BS.1864. There was a discussion about measuring the contribution of the LFE channel- awaiting technical input on best solution, for example, changes to 'K' weighting function.
Perceptual quality (PEAQ)
It is proposed to extend the stereo model to multichannel (5.1). There is currently only one subjective test database; it was felt during the meeting that there should be more. Noted that the proposed measurement model is based on a model from 1998; the meeting felt that this source model should be updated before expanding from stereo to multichannel audio.
Voice Quality measurement PESQ
A technique called Objective Listening Quality Assessment (P.OLQA) models speech quality through digital speech signal analysis. More recently, it has been proposed to extend the technique from voice band to wider bandwidth (up to 15kHz, voice HD). P.OLQA may eventually replace the subjective model, Perceptual Evaluation of Speech Quality (PESQ). However, it is not expected that it would be used for music signals, but only for voice.
AES-X187A and AES-X187B, Major rewrite of AES 17
There is an early outline document on our document site. An additional request has been received to clarify the term "dBFS" more precisely.
Harris reported that T. Kite has been unwell, but is getting better now and he understands that Kite is expecting to be able to carry on leading the revision work. Hopefully, Kite will be able to clean up and progress the documents in advance of the next AES convention, and also attend the next meeting in person.
Liaisons
There was some discussion about EBU meetings to discuss:
AV Synchronisation
Possibility of publishing a lip-sync cookbook
Also mentioned was some fingerprinting technology to ensure lip-sync by Miranda, Evertz and Dolby. A demonstration is planned for June 2010 in Montreal. P. Treleaven will provide feedback to this group.
New Projects
No new projects were proposed
New Business
There was no new business
The next meeting will be during the next convention in 4-7 November 2010 in San Francisco, USA.
