TLSA player: A tool for presenting consistent smil 2.0 documents

Describing synchronization constraints in complex Interactive Multimedia Documents at authoring time can be an error-prone task, especially if the increasing number of media objects participating in these relations is considered. As a consequence, some synchronization constraints specified by the author may not be satisfied, leading the presentation of the document to undesirable deadlocks or to unexpected misbehaviours, characterizing the occurrence of an inconsistency. In particular, the flexibility of high level authoring models (such as SMIL 2.0) for the edition of complex IMDs can lead authors, in certain cases, to specify inconsistent documents. For this reason, it is important to apply multimedia players that can ensure the presentation of consistent documents. This paper presents the main aspects of the development of a multimedia player which ensures the presentation of consistent multimedia documents, the TLSA Player. The TLSA Player is part of a formal methodology for the design of multimedia documents which provides the formal semantics for the dynamic behaviour of the document, consistency checking, and the scheduling of the presentation taking into account the temporal non-determinism of these documents.