一种基于组播的视频转码系统的设计与实现

视频会议是一种支持人们远距离进行实时信息交流、开展协同工作的应用。基于组播骨干网(MBone)的视频应用已成为研究的热点。目前,在组播视频会议中,视频发送者基本上都是按事先设定的带宽进行数据发送。这种按固定速率发送视频的方式无法同时满足所有接收者对视频质量的要求。该文提出并实现了一个视频转码系统,该转码系统被配置在窄带网络和宽带网络的连接处,一方面接收来自宽带网络的组播视频数据,另一方面能够针对窄带网络的可用带宽对接收到的视频数据进行码率转换,实时降低输出视频的码率并将转码后的视频发送到另一个组播组,使窄带网络上的用户能通过该组播组参与视频会议。

Design and Implementation of a Video Transcoding System

The rapid deployment and development of Internet has directly promote d lots of applications,video conference is a kind of application which can provide remote real-time communication and distributing cooperation.Researches on Multicast-Backbone(MBone)based multipoint video conference have gained more concerns recently.But in most current video conference systems ,such as vic,all video /audio are transmitted at a uniform rate from sources to all receivers.This method fails to satisfy all receivers due to heterogenous network condition.This paper overcome s this problem by designing and implementing a video transcoding system,which connects two heterogenous networks.The transcoding system receives high bit rate stream from high speed network and cast down it to low bit rate stream,which is suitable for low speed network.It achieves this goal through real-time video transcoding and makes users from low speed connection can also join video conference.