【作者】 杨明玮；

【导师】 侯整风；

【作者基本信息】 合肥工业大学 ， 计算机软件与理论， 2004， 硕士

【摘要】 通过因特网对现场或存储的视频进行实时传输是流媒体的主要内容之一。然而，由于当前因特网具有尽力而为的特性，它不为视频流提供任何的服务质量保证。此外，因特网的异构性使得它难于在视频组播中灵活地提供服务，从而满足用户宽范围的服务质量需求。因此，如何在因特网上传输高质量的视频流是当前的一个重要课题。 本文首先介绍了流媒体技术的现状和发展趋势，分析了传统视频编码方法不适用于网络传输的原因，详述了面向传输的FGS视频编码方法及其特性。在此基础上，本文提出了一个基于FGS的拥塞控制机制。该拥塞控制机制通过RTCP提供的QoS反馈信息和丢包模型来确定视频流的发送速率，并根据FGS码流结构进行码率整形，使得视频流的发送速率能够动态地适应网络带宽的波动，从而最大限度地提高视频质量。最后，本文设计并实现了一个基于FGS的视频流系统。实验结果表明该拥塞控制机制能够实现一定的TCP友好性，并且能够保证视频质量随着网络带宽的波动而平稳地变化。更多还原

【Abstract】 Real-time transport of live or stored video is one of the predominant parts of streaming media. However, the current best-effort Internet does not offer any QoS guarantees for streaming video. In addition, the heterogeneity of the Internet makes it difficult to efficiently support video multicast while providing service flexibility to meet a wide range of QoS requirements from users. Thus, how to transport streaming video with high quality is currently an important research issue.At first, the thesis introduces the status and development trend of streaming media, analyzes the reason that the traditional video coding techniques are not suitable for network transmission, and then expatiates the FGS video coding technique and its characteristics. On this basis, the thesis presents a FGS based congestion control mechanism. The mechanism determines the sending rate of video traffic based on packet loss model and feedback information about the network QoS provided by RTCP, and then adjusts the sending rate to the available network bandwidth through the use of rate shaping based on the structure of the FGS bitstream, so the optimal video quality is achieved. At the end of the thesis, a streaming video system is developed. The experimental results show that the mechanism can achieve the TCP-friendly behavior and the smooth variation of video quality while the network bandwidth varies.更多还原