Report of meeting of the SC-02-14 Working Group on Internet Audio Delivery Systems of the SC-02 Subcommittee on Network and File Transfer of Audio held in conjunction with the AES 118th convention in Barcelona, Spain, 2005-05-29
The meeting was convened by K. Brandenburg.
The agenda and the report of the previous meeting held in San Francisco, 2004-10-29 were approved with amendments.
Development Projects
AES-X074: Recommended Practices for Internet Audio Quality Description (IAQUAD)
The draft is still missing the reference sentence about the quality of the AES-X074 scale which M. Yonge agreed to add at the last meeting.
Otherwise the draft text is completely approved at the last meeting.
For the conclusion of the project a list of audio test items required to conduct a test according to the drafted procedures was still missing.
Because all previous attempts to gather appropriate test material from external sources failed, a new list of test items was assembled. This list contains test material from the EBU SQAM CD, as well as tracks from commercial CDs and other specific test items. The test items combine a broad range of audio material and, at the same time, critical items for audio codecs.
EBU have already given oral permission to use the SQAM test material for the AES purposes. A written agreement should be set up between EBU and AES for finalizing the usage and publication matters (CD or website). The AESSC secretariat will arrange for that. The SQAM CD can be also bought from the ITU.
The original source for the test item "Carmen" is still sought for. New information on the source will be added to the list by Mark Yonge when available and before publication.
For the item, "pitch pipe" a clearance letter from Dolby was already received. The Institute fuer Rundfunktechnik sent a clearance letter regarding the item "ice hockey".
In the following the other test items were explained in more detail.
All test items are a resample 48 kHz (sampling rate) version. Therefore the commercial versions of audio items from CDs need to be modified. In the draft of SC-02-14 it has to be defined how to resample the tracks.
The list of audio test items and the audio material itself will be published on the website or on a special AES CD. The AESSC will decide which way the publication process will be handled. Paul Jessup will arrange for the clearance of the commercial tracks. If publication on CD is chosen, the price for the CD will only cover the expenses. No additional fee will be charged.
Everything was agreed on, the editorial changes need to be added and then the draft with all additional material can be send out for Call for Comment.
Liaison
ITU-R Study Group 6Q
T. Sporer reported. ITU-R WP6Q, the group in charge of quality assessment, is revisiting ITU-R Rec. BS.1387-1 (PEAQ). This recommendation currently is validated to simulate listening tests according to ITU-R Rec. BS.1116-1. Like BS.1116 PEAQ is focused on high quality audio. In its current version PEAQ is only specified for mono and stereo signals.
Since the finalisation of PEAQ, newer audio coding schemes - which are now more wave-form preserving - and the new listening procedure ITU-R Rec. BS.1534 (MUSHRA) have been developed. MUSHRA is targeting intermediate audio quality levels.
ITU-R TG 6/9 asked for advice from ITU-R WP6Q concerning objective measurement of spatial audio quality especially for "large screen digital image" LSDI applications. ITU-R WP6Q therefore started investigations on objective perceptual quality assessment in two directions:
- Assessment of audio quality at intermediate audio quality levels (below the target range of BS.1116, and in accordance to BS-1534)
- Assessment of spatial audio quality (extending PEAQ for multi-channel and spatial audio)
ITU-R WP6Q has set up a raporteur (Sporer) who has the mandate to collect all information about listening tests, e.g. MUSHRA, work on spatial topics, perceptual measurements, extensions of PEAQ, information concerning intermediate audio coding etc. The goal is to evaluate measurements with PEAQ to see how it performs, where it fails etc. It should also serve as a start for a database for future scientific work in ITU-R WP6Q. This call for input has been sent also to ISO/MPEG, SMPTE and EBU. The material will be collected by Sporer via email and will be incorporated in report due to next meeting of the ITU-R WP6Q in the fall of 2005.
Sporer pointed out that currently the Secretariat of ITU-R has some problems to address liaison letters correctly to AES. He proposes to set up a liaison project at the AES to have an address for ITU-R to send material to concerning this work item. Yonge pointed out that the process of getting formal relations between AES and ITU was going on in the period before he became standards manager of AES. There might have been some interrupt in the negotiations due to the change of contact persons on both sides. Mark Yonge will now contact the responsible Counsellor of Study Group 6, Gerardo Messias. Sporer promised to send additional material regarding this issue to the AESSC secretariat to support a liaison project.
New Projects
No new projects were proposed or requested
New Business
If comments come in regarding this project it is appropriate for the group to exist further. In the long term the mantenance of the project will be moved to SC-02-01 together with the just initiated liaison. It is expected that SC-02-14 will be retired without further meetings.
The next meeting will be held in conjunction with the AES in New York in fall 2005 provided only that there is a need to handle issues related to AES-X074.
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