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