Representing Digital Assets for Long-Term Preservation using MPEG-21 DID
  Various efforts aimed at representing digital assets have emerged from several communities over the last years, including the Metadata Encoding and Transmission Standard (METS), the IMS Content Packaging (IMS-CP) XML Binding and the XML Formatted Data Units (XFDU). The MPEG-21 Digital Item Declaration (MPEG-21 DID) is another approach that can be used for the representation of digital assets in XML. This paper will explore the potential of the MPEG-21 DID in a Digital Preservation context, by looking at the core building blocks of the OAIS Information Model and the way in which they map to the MPEG-21 DID abstract model and the MPEG-21 DIDL XML syntax. 
Jeroen Bekaert, Xiaoming Liu, Herbert Van de Sompel