Middle-tier for multimedia synchronization

The gap between the synchronization specification and the synchronization model limits user interactions for a multimedia presentation. The middle-tier for multimedia synchronization handles the synchronization rules that are directly extracted from the specification. In addition to these rules, the middle-tier also manages implicit synchronization rules which are not specified but can be extracted from other rules. The synchronization rules generated by the middle-tier assists the synchronization model to provide user interactions while keeping the synchronization specification minimal. We give examples of how these rules are generated from SMIL expressions.