中文摘要：

IP网络带宽的动态特性是流视频要面临的关键问题.可伸缩编码的视频具有带宽适应性,但由于其每一层编码通常是变比特率的,那么在视频传输中,为迎合动态传输带宽,如何裁减这种分层的变比特率视频,并极大化一定的目标性能,需要传输优化.针对上述问题,提出了一个预取或缓冲优化的流视频带宽适应性传输框架,将裁减策略放到一个窗口来考虑,解决了窗口内的最小裁减量问题,其带宽适应性粒度在理论上可以细化到“比特位”，并为其他裁减算法提供综合优化的计算平台.

英文摘要：

In recent years, the streaming video applications have led to a huge market. But dynamic behavior of the IP network＇s transmitting bandwidth makes it difficult to provide perceptually good quality of streaming video. The recent technologies of FGS and SVC video coding are proposed to deal with these problems by distributing the data in enhancement layers over a wide range of bit rates. However, data rate of the FGS video coding exhibits significant variability. This variability is meanwhile faced with the problem of the available network bandwidth variability. Therefore, the streaming is faced with the problem of trying to accommodate the mismatch caused by both the available bandwidth variability and the encoded video variability. By using the technologies of prefetching and buffing, this paper focuses on how many encoded video bits of the FGS video should be truncated, and how to truncate them when network available bandwidth isn＇t enough firstly. Then a scheme of the bandwidth adaptation video transmitting is developed through minimizing to truncate the encoded video bits, and the amount of truncated video bits are analyzed, which can achieve the minimum result theoretically. The scheme can provide a platform of how to compute truncating bit amount for other analogous algorithms. Finally, experimental results show the scheme is efficient and feasible.