视频流传输中的网络编码综述

网络视频应用增长迅猛，利用网络编码（NC）来提高网络吞吐量和传输可靠性进而改善视频流传输质量成为研究热点。针对如何优化网络编码进行视频流传输这一问题，必须要结合视频流自身特性作出改进并综合考虑所处的网络环境，才能充分发挥网络编码的优势。首先回顾了网络编码的基本概念和方法；然后对网络编码应用于视频流传输时需要考虑的视频业务特性，包括进行不等差错保护以优先保障重要等级视频数据包、降低数据包传输延迟以满足视频流实时性需求、增强网络差错恢复策略以提升传输可靠性等作了分析和归纳；接着阐述了基于网络编码的视频流传输策略在包括P2P、多源协作及内容中心网络等典型场景中的应用；最后对网络编码应用于视频流传输的研究趋势进行展望。

Overview of network coding for video streaming

With the explosive growth of video streaming applications, the use of Network Coding (NC) to improve the network performance and then to provide a better quality of video streaming is becoming a hot topic. In order to efficiently exploit the benefits of NC for video delivery, the proposed transmission strategies should be adapted for the characteristics of video traffic and the network environment should also be considered. Firstly, the basic concepts and methods of NC were presented. Then, a variety of NC based techniques that have been specifically designed for video streaming were analyzed and summarized into three main categories, including unequal error protection to give priority to important video packets, reducing packet transmission delay to meet realtime video streaming requirements, enhancing network error recovery strategy to improve transmission reliability. Thirdly, the applications of video streaming with NC in the P2P networks, multi-source cooperative and content-centric network scenarios were introduced respectively. Finally, based on this study, open issues and further research topics were elaborated.