一种新型的VBR视频传输方法

保证变比特率(VBR)视频流在IP网络上的平滑传输一直是多媒体通信领域研究的热点.传统的PCR协助的恒定速率传输方法利用了嵌入到视频码流中的程序参考时钟(PCR)来定期校正发送速率,是以较高的传输速率为代价减少了播放低码率视频流时的缓存需求.为了同时适应高码率视频流的鲁棒传输,本文提出了一种改进的方法,通过对发送速率进行更细粒度的调整和服务器端的自适应缓冲机制,进一步平滑了传输速率,而且没有增加终端缓存的需求.仿真实验的测试结果表明,改进的方法能更好地服务于各种码率的流媒体传输与回放,适用范围更加广泛.

A Novel VBR Video Transmission Method

How to guarantee the smooth transmission of video streams over IP network has been a hotspot at the area of multimedia communications.The traditional PCR-assist CBR schemes employ the timing information provided by the Program Clock Reference(PCR) embedded in the video streams to regulate their transmission,which reduce the buffer requirement at the cost of higher transmission rate when playing low-rate video streams.For the robust transmission of video streams with high rates,a novel transmission method is presented in this paper.It uses more detailed time scale and self-adapting buffer mechanism at the server side to smooth the rate variation further.Simulation results show that this method serves best for the transmission and playback by slowing down the transmission rate without higher buffer requirement.