THE MPEG-21 MULTIMEDIA FRAMEWORK: CONVERSIONS AND PERMISSIONS

In the area of multimedia computing and communication, one of the major objectives currently being pursued is Universal Multimedia Access (UMA), i.e., enabling users to transparently access any kind of content from anywhere, anytime, with any device. In the course of the MPEG-21 (Multimedia Framework) activities, the ISO/IEC MPEG standardization group has created essential building blocks toward this goal, mainly metadata standards. Two of them are worth noting here: (1) the Digital Item Adaptation (DIA) specification, including normative vocabulary and formats to describe the multime-dia consumption context (device, network, natural environment characteristics, user preferences) and to steer media adaptation operations required for UMA; (2) the Rights Expression Language (REL) and Rights Data Dictionary (RDD) specifications, providing terms and a language to express permis-sions on the usage of the media (who, how, what, under which conditions). In this paper, we describe a recent MPEG-21 DIA Amendment in this area, specifying description formats for: (1) multimedia conversion capabilities, which tool or service providers may use to norma-tively specify the media adaptation (conversion) capabilities of their tools or services, respectively; (2) permissions and conditions for multimedia conversions, which can be utilized by content providers t