分布式多媒体系统模型与传输控制算法的研究

作为分布式多媒体系统通信与表现控制研究的基础,提出分布式多媒体系统整体模型DMISIM(Distributed Multimedia Information System Integrated Model),将分布式多媒体系统抽象为3元组--多媒体同步时间单元SIU(Synchronization Interval Unit)、通信信道以及信道与SIU序列之间的一一映射关系．模型描述多媒体信息和通信网络的静态属性,反映系统通信传输的动态过程．基于DMISIM,对分布式多媒体通信传输控制机制进行研究,提出最小偏差调度算法MDSA(Minimum Deviation Scheduling Algorithm)作为古典列表调度算法CLSH(Classic List Scheduling Heuristic)的改进．理论分析和逻辑推导证明,在不增加算法时间复杂度,不降低多媒体同步表现质量的同时,算法提高了系统目的端缓冲区利用率,降低了缓冲区需求及多媒体数据溢出的可能性．算法与底层通信传输机制无关,可以广泛应用于分布式多媒体系统的通信传输过程中．

Research on integrated model and transmission controlling algorithm for distributed multimedia information system

To resolve the synchronization for multimedia communication and multimedia presentation of distributed multimedia system, a distributed multimedia information system integrated model(DMISIM) was put forward. In this model, distributed multimedia information system was formulated as synchronization interval units(SIU), communication channels and a mapping from the channels to the SIUs sequence. DMISIM describes not only the static attributes of multimedia information and communication channel but also the dynamic processes of multimedia communication transmission. Based on DMISIM, distributed multimedia communication transmission mechanism was researched and minimum deviation scheduling algorithm(MDSA) was described as the improvement of classic list scheduling heuristic(CLSH). It is proved by theoretical analysis and logical deduction, that MDSA has better performance than that of CLSH in such fields as channel usage factor, capacity requirement of destination buffers, whereas the algorithm complexity and multimedia synchronization quality are stable. MDSA is independent of communication subnet transport mechanism and can be widely used in multimedia communications.