Specifying and executing interactive multimedia presentations using the formal approach

Providing interactive functions is becoming an essential issue for many multimedia applications. Since user interactions, e.g., reverse, skip, freeze-restart, and scale, can be issued randomly and unpredictably, it is not easy to design interactive multimedia presentation software. In this paper, we propose a Dynamic Extended Finite State Machine (DEFSM) to achieve software modeling of interactive multimedia presentations. Using the DEFSM-based approach, each medium's behavior, i.e., intra-medium synchronization, is represented by an Actor DEFSM; the inter-media's relationship, i.e., inter-media synchronization, is represented by a Synchronizer DEFSM. To re-synchronize media display when presentations are resumed, some control schemes should be adopted during the processing of each user interaction. These interaction-based synchronization issues, i.e., dynamic properties of user interactions and re-synchronization control schemes, can be formally represented and resolved using DEFSMs. Based on the proposed DEFSM approach, a specification and execution system for interactive multimedia presentations has been developed on SUN SPARC workstations.