Predictable Processing of Multimedia Content, Using MPEG-21 Digital Item Processing

Within an MPEG-21 architecture, the two key concepts are the Digital Item, representing multimedia content, and Users, interacting with this content. MPEG-21 introduced Digital Item Processing to allow content authors to describe suggested processing of their Digital Items. It standardizes ways to insert functionality into a Digital Item, as such, creating a dynamic and interactive multimedia format. Moreover, if a terminal wants to support Digital Item Processing, it needs to provide an execution environment offering basic functionality. The semantics of this functionality have been standardized, however there is significant room for interpretation. Consequently, a Digital Item author may not be aware of the actual processing when using this functionality. In this paper, a system is proposed, compliant with the Digital Item Processing specification, to give content creators full control on the processing. This allows creating advanced predictable multimedia systems in an MPEG21 environment.