The electronic version of this International Standard can be downloaded from the ISO/IEC Information Technology Task Force (ITTF) web site.
ISO/IEC 21000-2:2005 specifies:

• Model: The Digital Item Declaration Model describes a set of abstract terms and concepts to form a useful model for defining Digital Items.
• Representation: The Digital Item Declaration Language (DIDL) is based upon the terms and concepts defined in the above model. It contains the normative description of the syntax and semantics of each of the DIDL elements, as represented in XML.
• Schema: Informative XML schemas illustrating complete grammars for representation of the DID in XML conforming to the normative representation.
• Detailed Examples: Illustrative (non-normative) examples of DIDL documents are provided to aid in understanding the use of the specification and its potential applications.

The ISO/IEC 21000 (MPEG-21) series of International Standards defines an open framework for multimedia delivery and consumption, with both the content creator and content consumer as focal points. The vision for MPEG-21 is to define a multimedia framework to enable transparent and augmented use of multimedia resources across a wide range of networks and devices used by different communities.
This second part of MPEG-21 (ISO/IEC 21000-2:2005) specifies a uniform and flexible abstraction and interoperable representation for declaring the structure and makeup of Digital Items. A Digital Item Declaration (DID) involves specifying the resources, metadata, and their interrelationships for a Digital Item. A DID is done using the Digital Item Declaration Language (DIDL).