SC-03-07 meeting, Amsterdam, 2008-05

Report of the meeting of SC-03-07 Working Group on Audio Metadata of the SC-03 Subcommittee on the Preservation and Restoration of Audio Recording, held in Amsterdam, 2008-05-19

The meeting was convened by chair C. Chambers

The agenda was agreed as written. It was noted that the contribution on the EBU P/MAG group will come into the agenda item on projects AES-X098 and AES-X134. The report of the previous meeting was accepted as written.

Open projects

AES R9-2008, AES standards project report - Considerations for standardising AES metadata sets
This report has now been published and provides advice for those considering providing AES metadata sets. This report is recommended as important reading for anyone developing metadata structures within the AES.

Development projects

AES-X071: Liaison with SMPTE Registration Authority
Project scope: to formalize a working relationship with the SMPTE Registration Authority

The secretariat reported that the AES has now acquired a class 13 entry in the SMPTE metadata dictionary (see RP210) and this means that the AES can now publish metadata objects specific to our industry in an open way. The AES is now in a position to formally publish dictionary entries as required. However, some procedure will need to be put in place within the AES to process metadata objects produced within standards, to assess if current metadata dictionary entries adequately describe particular objects and the way they are intended to be used, or if an additional class 13 entry will need to be generated to cover a particular requirement.

AES-X098A: Descriptive metadata for audio objects
Project scope: 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.

This project and AES-X134 was discussed together here.

A task group was held earlier in this convention where AES-X098A and a draft copy of EBU Tech Doc 3293 were compared and were seen to be almost identical. This is not surprising as they are both trying to describe the same thing but with slight differences in style. This raises the question of whether it would be sensible for the AES to consider publishing descriptive metadata for any particular segment of our industry or if that should be left to that segment to publish for themselves? Should the EBU publish this for the Broadcasting industry, the music industry do this for themselves and so on while the AES concentrates on core administrative, structural and technical elements?

A discussion then ensued and a representative from the EBU work described the development of the Draft Tech Doc 3293 and their proposals for AES-X134. This is based on Dublin Core elements (as was AES-X098A) and the EBU believe that this is core to all metadata structure as they see it. This is produced as an XML implementation and one benefit of this is the core of this XML structure can be extended for particular circumstances if needed without destroying the compatibility of the core. However, one of the ideas behind AES-X134 was to also produce a common set of core XML tag names to aid compatibility as these tags will be required to be accessed by different products and processes while retaining a common meaning to the objects they refer to.

It was suggested that it could be possible that the AES and the EBU could produce a common information document and refer to the EBU Tech Doc 3293 as appropriate. The AES standards secretary will review the EBU draft document and cross check with AES-X098A to assess if a common recommendation was feasible. Further discussions took place on issues such as how to represent time code or samples as this demonstrates one of the areas where elements are not common across our industry and certainly have different requirements to video. However T. Vaervagen of NRK (Norwegian Broadcasting) suggested that methods of accommodating these differences were possible within the EBU Tech Doc 3293. It was proposed that an item of joint work is carried out to produce a common information document to assist our industry in implementing descriptive metadata. NRK will work with the AES to produce a proposal.

AES-X114: Metadata review
Project scope: 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 only item to report on this occasion is the AES Class 13 registration in the SMPTE metadata dictionary.

AES-X134: Core audio metadata set and XML tag definitions
Project scope: "Develop a core audio metadata set and to study and produce a standardised set of XML tags, along with their definitions, that describes the core set of metadata to accompany professional audio when being transferred by file or streamed formats and define these within the SMPTE metadata dictionary."

This area links with the discussion already have had in the AES-X098A section on this meeting. It was agreed that the wording in the scope of this project needs to be adjusted to read "core metadata for audio exchange" rather than "core audio metadata set" and that the work being carried out with the EBU will compare the work described in AES-X098 and this project. The outcome of this comparison will be discussed on October at our next meeting but it was hoped that a common recommendation could be produced between the AES and the EBU work.


There is informal liaison with the EBU P/MAG group as at least one member of this group is also a member of that EBU group.

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 125th Convention in San Francisco in October 2008.

AES - Audio Engineering Society