分布式多媒体交互协作系统中实时协调机制的研究

Study on Real Time Coordination Mechanism for Distributed Interactive and Cooperative Multimedia System

针对多媒体交互协作系统中的组同步问题,提出了基于多播的实时协调机制.结合多播服务,采用生成具有延迟限制的最小延迟抖动多播树的方法来选择虚拟协调服务器,利用该服务器转发用户操作信息,在保证系统实时性的前提下使延迟抖动降到最小,以实现组同步功能,并能在系统或网络发生变化时自动地调整虚拟服务器的位置.仿真结果与实际应用都表明,实时协调机制有效降低了延迟抖动,使系统交互质量得到明显改善.

In order to solve the problem of group synchronization in interactive and cooperative multimedia systems, a real-time coordination mechanism is presented. Combining multicast services, a multicast tree (method) with bounded delay and minimum delay jitter is built to select a virtual coordination server that is used to multicast the operation messages to users. To achieve the group synchronization, the delay jitter is reduced to the least under the condition that the system can be run in real-time. The virtual sever can be adjusted dynamically when the system or the network is changing. Simulation results and practice application show that the delay jitter of the system is reduced efficiently and the interaction quality of the system is improved.