SC-07-01 meeting, New York, 2015-10

Report of the meeting of the SC-07-01 Working group on Audio Metadata held in New York, NY., US, 2015-10-31.

The meeting was convened by chair C. Chambers.

The agenda and the report of the previous meeting, held in Warsaw, Poland, 2015-05-09, were approved as written.

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
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.

AES60-R Review of AES60-2011, AES standard for audio metadata - Core audio metadata
status: Revise to harmonise with EBU T3293 V1.6

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 had sent an update to the mapping of the AES namespace to the schema in order to correctly apply the amendment to harmonize with EBU T3293 v1.6.

The meeting discussed issues with the annotations to the new proposed schema so that these definitions of the schema attributes. It was understood that the important issue for programmers was the schema while the important this from the AES standards point of view was the clear definition of the element descriptions. It was agreed that the Standards manager will extract the definitions and work on any that needs clarity with Tormod help as needed. There was a discussion around the EBU move towards RDF while maintaining the XML schema and the object models.

Development Projects:

AES-X098C Administrative metadata for audio objects - Process history schema
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. status: D. Ackerman to advise if this project should be closed.

This should be close if there is no progress and the requirements have moved on with the developments in AES60-R and RDF. A secretarial draft was carried out on this project in 2008. The chairman will discuss with David Ackerman.

AES-X114 Metadata review
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.

Following on from the last meeting report, the meeting discussed the progress with the loudness compliance signalling brought to the last meeting by Australian Broadcasting. To reiterate, 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 had 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 AES has sent information around AES41 but as yet we await ITU formal request for liaison and information as how we can support this work.

AES-X155 AES standard for audio metadata - Production recording metadata set (iXML)
scope: This document specifies a format for communicating file- and project-based production metadata between various stages of production and post production workflow. It may also have utility in other areas. The format, iXML, uses the XML standard for communication of tagged metadata. The XML-formatted metadata may be written to a data chunk inside a Broadcast Wave file, such as AES31-2, or some other suitable file type. iXML standardises the interchange of production information, and provides an extensible framework to add new private or public data as needs develop, while permitting the specification to be expanded in a consistent and compatible manner.

Deferred to 2016 to await harmonization with updated AES60.

AES-X214 XML implementation of AES31-3
scope: Create an XML schema that fully represents AES-31-3 ADL documents. Supply XSLT style sheet 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 this meeting. Following this two week period if no further comments have been received, this document will be moved on to the next stage.

Since the meeting no further comments to the draft have been received and this is therefore complete and should move forward to publication.

AES-X224 Best Practices for the Management of Embedded Metadata in Audio Files
scope: To create a guide for manufacturers of audio hardware, software and computer platforms describing best practices for the management of metadata embedded in audio files.

The meeting discussed this project and it was proposed that the project provides a set of simple statements that either sets out rules around embedded metadata in wave and broadcast wave file or provide an overarching set of rules starting with broadcast wave file and adding to this as time goes on.

This can get more complex when looking at metadata in the XML chunk. It was suggested that this could be set out as a high level framework. It was agreed that a set of high level statements will be shared with this group to progress this project. These could be published as the start of a "Best practice" framework.

The problem as discussed in this meeting is when audio applications update audio files, what metadata should be updated and what should be done with existing information contained in files. Too frequently, applications just ignore existing metadata or unique references and simply write new data in isolation. This project aims to provide guidance as to how to deal with metadata flow as audio files progress through various work processes.

The meeting agreed that this was an important area of work and a draft should be produce and sent to this group for the next meeting.


No further liaisons to discuss

There was a general question on how would we carry ISRC data in audio systems and it was suggested that this could be carried in AES60.

New Projects

No new projects

New Business

No new business

The next meeting will be scheduled in conjunction with the AES 140th Convention in Paris, June 2016

AES - Audio Engineering Society