A Framework for Composition, Verification and Real-Time Performance of Multimedia Interactive Scenarios

Abstract

Interactive Scores (IS) is a formalism for composing and performing interactive multimedia scenarios. In IS, the composer defines temporal relations (TRs) between temporal objects (TOs) in order to specify the temporal organization of the scenario. During execution, the performer may trigger interaction points to modify the star/stop times of TOs, while the system guarantees that all the TRs are satisfied. IS is implemented in the tool I-SCORE and its semantics is formally defined as a Hierarchical Time Stream Petri Net (HTSPN). However, this model is not able to represent branching behaviors that are necessary to properly deal with applications such as video games and museum installations. Moreover, HTSPN does not provide tools for the automatic verification of critical properties of scenarios. In this work we define a semantics for IS based on Timed Automata (TA) and we show that such model yields to a complete framework to compose, verify and execute interactive scenarios. More precisely, we show that: 1) our model is able to deal with conditional statements in IS; 2) efficient verification techniques can be now used to reason about the written scenarios; and 3) our model allows for a directly implementation on a reconfigurable device, thus guaranteeing a real-time performance.