Playout Management in Multimedia Database Systems

Abstract

The presence of multiple multimedia data streams, e.g., an audio data stream in conjunction with several video data streams within a complex advertisement show, which presentation must proceed in a mutually synchronized manner, is one of the unique features that distinguishes digital multimedia data from traditional, conventional, alphanumeric data. Sample applications in which this property of digital multimedia is especially important are electronic publishing, digital libraries, computer-based training or teaching (edutainment), advertisement, entertainment, and infotainment. Here, to form modularly structured presentations, multimedia information is “glued” together by designers (i.e., presentation authors) in a preorchestration phase. While some standards relevant for this phase such as SGML/HyTime [18] or MHEG [30] are more oriented towards multimedia/hypermedia documents, others such as PREMO [17] and ScriptX [47] emphasize more time-based multimedia presentations. The result of this phase is a predefined/preorchestrated multimedia presentation for which it is assumed that its realization is requested many times by many different (possibly simultaneous) users. Many multimedia application domains such as those mentioned before need to support a pool of such preorchestrated multimedia presentations. Support of user interactions is an important property to be provided within this context (“interactive multimedia”). It provides for users flexibility in presentation control by offering the possibility to adapt the presentation realization phase to the individual needs.