Multimedia document models: Sealed fate or setting out for new shores ?

Existing multimedia document models like HTML, MHEG, SMIL, and HyTime lack appropriate modeling primitives to fit the needs of next generation multime dia applications which bring up requirements like reusability of multimedia content in different presentations and contexts, and adaptation to user pr eferences. In this paper, we motivate and present new requirements stemming from advanced multimedia applications and the resulting consequences for m ultimedia document models. Along these requirements, we discuss the documen t model standards HTML, HyTime, MHEG, SMIL, and Z(Y)X, a new model that has been developed with special focus on reusability and adaptation. The analy sis and comparison of the models show the limitations of existing models, p oint the way to the need for new flexible multimedia document models, and t hrow light on the many implications on authoring systems, multimedia conten t management, and presentation.