Shared media space coordination: mixed mode synchrony in collaborative multimedia environments

Multimedia systems are often divided into presentational and conversational domains: those which orchestrate prerecorded scenarios and those which provide audio/video teleconferencing. To be effective across a wide range of activities, however, collaborative multimedia systems must support the integration of presentational, conversational and interactive multimedia within a single shared media space. Such a virtual environment must not only support synthetic and real-time media but also their interactive manipulation as shared objects. Therefore, synchronizing media and the actions upon them in both a timely and causal manner are necessary to maintain a semantically coherent workspace. This paper discusses these issues and introduces a framework based on Virtual Enablers and Virtual Barriers designed to support the diverse range of synchronization requirements within collaborative multimedia systems. Its associated architecture is described and the model's application to the field of telelearning is illustrated.