I spent this afternoon attending an introductory workshop on MPEG-21 DIDL, at the Watershed in Bristol, organised by UKOLN. The presenter was Frances Knudson of the Los Alamos National Laboratory Research Library. For the uninitiated, MPEG21 is a standard which “defines an open framework for describing multimedia applications” - although this can really mean anything!

The programme consisted of a whistle-stop introduction and overview of MPEG 21 DIDL, followed by some more hands-on theory where we were asked to create creating DIDs for various datatypes, based on what we had learned in the earlier session.

MPEG21 has 18 components, and this short workshop only really looked at parts 2 and 3, (Digital Item Declaration and Digital Item Identification respectively). Parts 5, 6 and 7 (Rights Expression Language, Rights Data Dictionary, Digital Item Adaptation) were mentioned in passing, but not explained in any depth.

I can see how this stuff would be useful - the model is deliberately abstract, and so can be implemented in a number of ways (XML, RDF, etc). The logic in the packaging of items, components and resources is fairly easy to grasp, but in the true way of metadata, you can pretty much do what you like, which is fine for individual repositories, but this means that true interoperability is still a way off (although the RAMLET project may assist with some of this).

MPEG21 currently has only one real competitor, which is METS, although most of the current major repositories which support one support plugins for the other, so you really do pay your money and take your choice.

A worthwhile session, which was well attended (and turned out to be part of a two-day workshop on content packaging which I now wish I was attending all of!).

NB. Notes and slides are being made available, and I will post these here when received.