Streaming Codes for Channels with Burst and Isolated Erasures

We study low-delay error correction codes for streaming recovery over a class of packet-erasure channels that introduce both burst-erasures and isolated erasures. We propose a simple, yet effective class of codes whose parameters can be tuned to obtain a tradeoff between the capability to correct burst and isolated erasures. Our construction generalizes previously proposed low-delay codes which are effective only against burst erasures. We establish an information theoretic upper bound on the capability of any code to simultaneously correct burst and isolated erasures and show that our proposed constructions meet the upper bound in some special cases. We discuss the operational significance of column-distance and column-span metrics and establish that the rate 1/2 codes discovered by Martinian and Sundberg [IT Trans.\, 2004] through a computer search indeed attain the optimal column-distance and column-span tradeoff. Numerical simulations over a Gilbert-Elliott channel model and a Fritchman model show significant performance gains over previously proposed low-delay codes and random linear codes for certain range of channel parameters

Live video streaming over packet networks and wireless channels

The transmission of live video over noisy channels requires very low end-to-end delay. Although automatic repeat request ensures lossless transmission, its usefulness to live video streaming is restricted to short connections because of the unbounded retransmission latency. An alternative is to use forward error correction (FEC). Since finding an optimal error protection strategy can be time expensive, FEC systems are commonly designed for the worst case condition of the channel, which limits the end-to-end performance. We study the suitability of two scalable FEC-based systems to the transmission of live video over packet networks. The first one uses Reed-Solomon codes and is appropriate for the Internet. The second one uses a product channel code and is appropriate for wireless channels. We show how fast and robust transmission can be achieved by exploiting a parametric model for the distortion-rate curve of the source coder and by using fast joint source-channel allocation algorithms. Experimental results for the 3D set partitioning in hierarchical tree video coder show that the systems have good reconstruction quality even in severe channel conditions. Finally, we compare the performance of the systems to the state-of-the-art for video transmission over the Internet. 1