MPEG-Pro, an authoring system for MPEG-4 with temporal constraints and template guided editing

From multimedia history, we can see that however powerful the technologies underlying multimedia systems, only relevant authoring applications will bring success to these systems. From this assumption, MPEG-Pro, an MPEG-4 authoring system prototype, has been designed to integrate all main authoring capabilities, from audio/visual encoding to the final delivery of a complete MPEG-4 application. Even if commercial tools are very popular in the authoring world, they all provide a specific proprietary solution. In this sense, the essential benefit of MPEG-Pro is to allow the production of standard contents. The MPEG-Pro architecture follows very closely the MPEG-4 structure. Therefore it inherits the benefits and the drawbacks of this format. Among these limitations, the MPEG-4 temporal model is based on time-stamped events and gives no means to express temporal dependencies between audio/visual objects. We introduce a solution to this limitation by adding a new layer to the authoring system to manage temporal constraints. In this paper, we present first the current authoring prototype. We describe its graphical interface and its modular architecture which allow a large scope of extensibility to be able to integrate new high-level authoring features. Then we present our introduction of temporal constraints to the editing system and our template system which aims at hiding much of the scene description complexity of MPEG-4