11 March 2009
The British Library publishes audio metadata profile
Chris Clark is Head of Selection and Documentation in the British Library Sound Archive. Chris reports:
As the ASR Board member responsible for overseeing the project’s metadata component I am delighted to report that the British L has now published the Metadata Encoding and Transmission Standard (METS) profile that was developed during the project and subsequently refined by Markus Enders. Markus is a METS Board member, so his involvement lends this profile a high degree of conformance and authority.
It would be fair to say that METS has presented the steepest learning curve for everyone in this project connected with documentation and resource discovery. Some were convinced it was the perfect solution to the requirement to have all the intelligence about an item held together in a single instance, while others regarded it as unnecessarily complex. But it was a requirement of the JISC to use common, interoperable standards and although one could rightly question the standard’s life expectancy and applicability in 2004 when the project began, five years later METS has been widely implemented in libraries and archives and has proved adaptable to a wide range of digital objects.
In devising a METS schema for sound the intention was not to establish a ‘discographic’ metadata standard: domain-specific solutions are an unworkable constraint where systems need to address many kinds of information. One of the key requirements for any metadata infrastructure is versatility: that there are a number of core components shared with other domains, each of which may allow local variations (e.g. in the form of extension schema) that are applicable to the object and its life-cycle. Another requirement, of particular relevance to multi-media objects like sound recordings, can be described as ‘relational’. This involves the correct expression of hierarchy, sequence and provenance. METS was found to be very good at expressing parent-child relationships (carriers and sides, sides and tracks, etc), pre-determined orderings (the scenes of a dramatic performance) and intelligence about the original source materials.
The essential thing that METS does is to faithfully represent physical, atomic reality in logical, virtual terms and in so doing reinforces the authenticity of any archived object.
Lorca Dempsey has defined metadata as ‘intelligence in support of more efficient operations’. METS is often described as a ‘wrapper’, a container of different kinds of information, each of which has its own prescribed place in the METS structure. This structure can be unwrapped, so it will be possible to filter out data from the descriptive metadata section and expose it to harvesting applications or re-use it in other display contexts, such as an exhibition or on-line publication. When you are looking for something within the ASR site you find neat arrangements of essential information concerning titles, performers and dates. All of this has been derived from the METS record that remains in the background unless deliberately brought to the browser.
All current BL metadata profiles are available under http://www.bl.uk/profiles/. The sound archive profile is available under http://www.bl.uk/profiles/sound/. It is not the end of the story. The xml version of the profile is awaited and born-digital acquisitions and acquisitions held and preserved as collections are expected to require small adjustments as variant profiles.