Implementation and Testing of ALM Based HDTV Live Prototype System
基于应用层组播的高清流媒体直播原型系统的实现和测试

In this paper,we applied ALM(application layer multicast) into HDTV live system,design and implement a multimedia live prototype system with large concurrency,high efficiency and low delay.We also created a distributed time-shifting algorithm,which was integrated in the system in order to allow users to watch both live and delayed TV programs.This prototype system was put into large-scale testing for more than one month in Fudan Campus during World Cup 2006.The result shows that it is a good solution to output bandwidth bottleneck at server side and long delay of normal P2P technology at the client.The maximum amount of online users was over 460.It also provides a good solution to HDTV live system,which is the focus of National Science and Technology Department.