MPEG-21 BSDL is a part of the DIA specification of MPEG-21. DIA (the seventh part of MPEG-21) specifies tools for the adaptation of Digital Items. The adaptation of a Digital Item results in adapted resources, adapted descriptions, or adapted Digital Items. BSDs are used to steer the adaptation of coded resources in the XML domain of the MPEG-21Multimedia Framework. Two technologies are specified in the DIA standard in order to generate these XML descriptions or BSDs, in particular, MPEG-21 BSDL and gBS Schema.
The MPEG-21 DIA standard has been finished in 2003 and can be obtained from the International Standardization Organization (ISO) as specification ISO/IEC 21000-7:2004.
A first amendment on this DIA specification has been finished in 2005. This amendment, called conversions and permissions, provides new tools that declare adaptation operations such as summarizing a video into a sequence of images. This amendment is an extension of the DIA standard and has not modified the BSDL specification. The amendment can be obtained from the ISO as specification ISO/IEC 21000-7:2004/Amd 1:2006.
A second amendment on the DIA specification has been finished in 2007. This amendment describes Dynamic and Distributed Adaptation. Besides the extensions to DIA in order to obtain a distributed adaptation framework capable to be used in a streaming environment, the second amendment also contains extensions and modifications related to the BSDL specification. In particular, the first version of the BSDL specification is characterized by an increasing memory consumption and decreasing execution speed during the generation of the BDS. In other words, the BintoBSD Parser contains a number of performance issues, certainly in the context of scalable video bitstreams. Furthermore, exponential Golomb coded syntax elements could not be parsed and there were no precautions to interpret emulation prevention bytes. All these issues are solved in this second amendment by defining context-related attributes, XPath variables, new built-in data types, and a mechanism to interpret emulation prevention bytes when necessary. The second amendment can be obtained from the ISO as specification ISO/IEC 21000-7:2004/FDAmd 2.