The Semantics of MPEG-21 Digital Items Revisited Christian Timmerer Maria Teresa Andrade and Pedro Carvalho Klagenfurt University, Austria INESC Porto, Porto, Portugal Universitätsstrasse 65-67 Rua Dr. Roberto Frias 378 A-9020 Klagenfurt P-4200-465 Porto +43 (0)463 2700 3621 +35 (0)122 2094000
[email protected] {maria.andrade,pedro.carvalho}@inescporto.pt Davide Rogai Giovanni Cordara Comm.it Telecom Italia Lab Via M. Deʼ Bernardi, 65 Via Reiss Romoli, 274 50145, Firenze. Italy 10148, Torino. Italy +39 (0)55 3434277 +39 (0)11 2286389
[email protected] [email protected] ABSTRACT A Digital Item (DI) is a structured digital object with a standard The MPEG-21 standard forms a comprehensive multimedia representation and metadata, i.e., it is the fundamental unit of framework covering the entire multimedia distribution chain. In transaction and distribution within the MPEG-21 multimedia particular, it provides a flexible approach to represent, process, framework. In other words, it enables the aggregation of and transact complex multimedia objects which are referred to as multimedia resources together with metadata, licenses, identifiers, Digital Items (DIs). DIs can be quite generic, independent of the intellectual property management and protection (IPMP) application domain, and can encompass a diversity of media information, and methods within a standardized structure. With resources and metadata. This flexibility has an impact on the level this definition in mind one can create Digital Items that are very of interoperability between systems and applications, since not all generic and independent of the application domain. Furthermore, the functionality needs to be implemented.