Network Coding of Rateless Video in Streaming Overlays
Network Coding of Rateless Video in Streaming Overlays
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DOI：
10.1109/tcsvt.2010.2087830
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发表时间：
2010-12
影响因子：
8.4
通讯作者：
N. Thomos;P. Frossard
中科院分区：
文献类型：
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作者：
N. Thomos;P. Frossard
我们提出了一种在有线覆盖网络中协作视频流的系统。我们提出了一种基于无速率编码和网络编码的方案，以提高系统吞吐量和客户端的视频质量。我们的混合编码算法允许有效地利用可用的源和路径多样性，而不需要昂贵的路由或调度算法。我们特别考虑了一种架构，其中多个流服务器同时向一组客户端传送视频信息。服务器对视频数据包应用 Raptor 编码以实现容错，并且覆盖节点有选择地组合 Raptor 编码的视频数据包，以增加系统中的数据包多样性。我们分析了选择性网络编码的性能并描述了其在实际视频流系统中的应用。我们进一步计算协作流系统中的有效源和通道速率分配。我们估计客户在编码选择方面的预期符号多样性。然后我们提出一个最小最大质量优化问题，该问题通过基于低成本二分法的方法来解决。实验评估表明，我们的系统通常优于不使用网络编码的 Raptor 视频流系统以及在网络节点中执行解码和编码的系统。最后，我们的解决方案复杂度低，并且只需要网络编码节点中的小缓冲区，这无疑是在实际流媒体系统中部署的两个重要优势。
We present a system for collaborative video streaming in wired overlay networks. We propose a scheme that builds on both rateless codes and network coding in order to improve the system throughput and the video quality at clients. Our hybrid coding algorithm permits to efficiently exploit the available source and path diversity without the need for expensive routing nor scheduling algorithms. We consider specifically an architecture where multiple streaming servers simultaneously deliver video information to a set of clients. The servers apply Raptor coding on the video packets for error resiliency, and the overlay nodes selectively combine the Raptor coded video packets in order to increase the packet diversity in the system. We analyze the performance of selective network coding and describe its application to practical video streaming systems. We further compute an effective source and channel rate allocation in our collaborative streaming system. We estimate the expected symbol diversity at clients with respect to the coding choices. Then we cast a minmax quality optimization problem that is solved by a low-cost bisection based method. The experimental evaluation demonstrates that our system typically outperforms Raptor video streaming systems that do not use network coding as well as systems that perform decoding and encoding in the network nodes. Finally, our solution has a low complexity and only requires small buffers in the network coding nodes, which are certainly two important advantages toward deployment in practical streaming systems.