【摘要】 为了克服基于应用层组播的流媒体系统中的不足,提出了一种新的基于多描述编码的组播方案。该方案以节点中缓存数据包的时序来划分系统的分层拓扑,较好地解决了不同描述间的同步,并降低了系统延迟。并通过分布式算法实现描述资源在各层中的均匀分布,加快了组播系统的收敛,实现了节点接受视频质量的无缝切换,从而在节点出度约束条件下较好地平衡了节点的负载,并提高了节点的贡献率。仿真实验表明,该组播方案提高了节点的接受视频质量,并具有良好的可扩展性和健壮性。更多还原

【Abstract】 To overcome the disadvantages of streaming media system based on application layer multicast,a novel scheme based on multiple description coding is proposed in which peers are allocated in hierarchical topology according to timesequence of data package cached in peers,the synchronization of descriptions and low system delay are achieved at the same time.The uniform distribution of descriptions in each layer is also achieved with distributed algorithm.It accelerates the convergence of multicast system,seamless handover of received video quality is achieved,load of peers is balanced under the constraint of outdegree and the contribution rate of peers is improved as well.Experiments demonstrate that this scheme improves video quality and achieves high scalability and robustness.更多还原