A GENERAL-PURPOSE MULTIMEDIA SYNCHRONIZATION MECHANISM-BASED ON CAUSAL RELATIONS

Designing distributed multimedia applications raises temporal and spat ial synchronization issues related to processing, transport, storage, retrieval and presentation of data, sound, still images and video, Wit hin this framework, the paper aims to define a general-purpose multime dia synchronization mechanism, known as the conditional delivery mecha nism, capable of addressing both intra- and inter-stream synchronizati on issues, The proposed mechanism, based on the identification of caus al relations among information units of one or several streams, is des igned to ensure that these Causal relations, expressed at the user's l evel, are satisfied when delivering the streams, The conditional deliv ery mechanism is analyzed in depth and both informal and formal specif ications of the mechanism are provided, The formal specification refer s to an extension of the standard formal description technique LOTOS ( RT-LOTOS for Real-Time LOTOS), Validation results of the conditional d elivery mechanism are finally presented for a distance and interactive training application.