Enriching SMIL with assertions for temporal validation.

In this paper we define a formal semantics for the language SMIL which can be used in a number of applications. First of all, we propose a computer aided authoring system which include a Semantic Validator Module for the evaluation of the temporal consistency of the resulting multimedia presentation. If any temporal conflict is found, the system returns to the user a message pointing out the tag which contains the error and its motivation. This helps the user to correct the error. We also introduce a notion of equivalence for SMIL tags which is useful to find a candidate for substitution in the development of complex multimedia structure, for example in the context adaptation process.