Operator Based Composition of Structured Multimedia Presentations

We are interested in a new class of multimedia presentations that include rich dynamic interactive scenarios. Such scenarios integrate dynamic user control over the flow of presentation, advanced processing of media content, and diverse sources of media streams such as live feeds or teleconferencing streams. We propose a new model for structured temporal composition of interactive dynamic multimedia presentations. It extends the notion of basic media segments to include executable code, live feeds, and links. In this way, we can take into account user interactions, content-sensitivity, new interesting sources of multimedia data, and provide support for sharing and reuse. These new media segment types are integrated in a seamless way within our temporal composition model. The model is based on Interval Expressions that involve media segments of unknown duration. We define a set of operators that express causal relations between intervals. Operators take time intervals as arguments and yield another interval as a result. They can be used to form nested interval expressions allowing specification of temporal compositions in a well-structured way. Interval Expressions provide a means of encapsulation and structuring: compound encapsulated intervals can be specified in terms of elementary media objects as building blocks. We address the temporal consistency problem—Interval Expressions guarantees the absence of temporal inconsistencies by construction.