视频广播、视频点播和视频会议都是视频应用的方式。 视频广播是基于ＩＰ组播技术的一种单向、一对多的广播服务，它带宽耗费小。对于每个节目，由于只发送一个视频数据流，因而理论上能够支持无限用户对节目的收看，比较适合大量观众的视频应用，是一种经济有效的视频应用。视 Video broadcasting, video on demand and video conferencing are all ways of video applications. Video broadcasting is a one-way, one-to-many broadcasting service based on IP multicast technology, which consumes less bandwidth. For each program, it is a cost-effective video application because only one video data stream is transmitted, so that it can theoretically support unlimited users to watch the program and is suitable for a large audience of video applications. Visual