SC-07-01 meeting, Warsaw, 2015-05

Report of the meeting of the SC-07-01 Working group on Audio Metadata held in Warsaw, Poland, 2015-05-09.

The meeting was convened by chair C. Chambers.

The agenda were approved as written. The report of the previous meeting, held in Los Angeles, US, 2013-10-11, was unavailable.

The formal notice on patent policy was read.

Projects assigned to this group but not mentioned here had no action requested or required - see for details.

Open Projects:

AES57-R, Review of AES57-2011, AES standard for audio metadata - audio object structures for preservation and restoration
No action was requested or required.

AES60-R, Review of AES60-2011, AES standard for audio metadata - Core audio metadata
The intent was to amend AES60 to harmonize with the revised EBU T3293 v1.5.

The meeting discussed the document posted on the work group site. One of the issues is the comparison of the schemas between the EBU and AES name spaces. Tormod offered his help in applying the AES namespace to the schema in order to correctly apply the amendment to harmonize with EBU T3293 v1.5. This will be synchronised with the publication of the audio model by the ITU.

It was problems with the updates to the AES schema that had prevented this project from progressing to date so it was hoped that this can now be progressed this summer that should now harmonize with EBU core v1.6.

Development Projects:

AES-X071, Liaison with SMPTE Registration Authority
The meeting felt that this project should now concentrate on merging a common audio core based on AES60 and its extensions. This project should be now closed.

AES-X098C, Administrative metadata for audio objects - Process history schema
The intent of this project is to collect information on all metadata issues pertaining to digital audio objects and all aspects of the digital documentation of digital audio objects. This scope includes field structures to describe and provide access to the audio content contained in digital files. It includes transfer, preservation and restoration information.
D. Ackerman to advise whether this project should be continued.

AES-X114, Metadata review
This project is to study and report on the methods and techniques for attaching and implementing metadata through all aspects of interfacing real-time and file-transfer audio, including, where related to audio, other metadata related to other media. The scope includes metadata for professional recording, sound reinforcement, production, broadcasting, and transmission as well as the exchange of metadata and associated audio among different organizations. It also includes the development of techniques, such as UML, to aid the description of the relationships and flow of metadata requirements in an open and recognised way.

The meeting discussed the possible needs for loudness compliance signalling brought to the meeting by Australian Broadcasting. This would in summary require the inclusion of metadata in audio file formats and audio stream interfaces to show if the audio being handled has already had its loudness normalised. This is to prevent loudness process being cascaded to the detriment of the audio quality. Work has started in the ITU Q138/6 and this meeting was asked informally if a request for liaison would be acceptable to cover this work.

The current proposal would most likely be in the form of a single flag to show that the audio has been normalised, a further compliance type to show which loudness standard has been applied, a flag to show if the whole content had been normalised or just parts (speech for instance) and a verification value (currently proposed to be the RMS value derived from 400 mS blocks of audio) that can be recalculated to ascertain if the audio had been altered since the normalisation had taken place. The verification value needs to be able to deal with lossey codec which is why this method has been proposed.

This proposal is just a starting point to await further discussions as this work progresses but it is hoped that this could be included in AES standards that deal with live and file based audio content. It would appear that AES41 part 5 may be the place for this work to be started. The meeting agreed that there are two parts to this work, the definition of the metadata probable to be dealt with in this group, and the method for carrying which should be dealt with in SC-02-02. We await ITU formal request for liaison.

AES-X155, AES standard for audio metadata - Production recording metadata set (iXML)
Deferred to await harmonization with the revised AES60.

AES-X214, XML implementation of AES31-3
This project will create an XML schema that fully represents AES31-3 ADL documents. An XSLT style sheet will be included for reformatting the XML document as EDML. The meeting agreed that this document looks to be complete and asked the working group to post any final comments in the next two weeks following the posting of these meeting notes. Following this two week period if no further comments have been received, this document will be moved on to the next stage.

AES-X224, Best Practices for the Management of Embedded Metadata in Audio Files
No information has been received from the working group in time for this meeting. This project is on hold


No further liaisons matters

New Projects

No new projects

New Business

No new business
The next meeting will be held in conjunction with the AES 139th Convention in New York, October 2015.

AES - Audio Engineering Society