Rate Distortion Optimized Mode Selection

Multiple description (MD) video coding can be used to reduce the detrimental effects caused by transmission over lossy packet networks. Each approach to MD coding consists of a tradeoff between compression efficiency and error resilience. How effectively each method achieves this tradeoff depends on the network conditions as well as on the characteristics of the video itself. This paper proposes an adaptive MD coding approach which adjusts to these conditions through the use of adaptive MD mode selection. The encoder in this system is able to accurately estimate the expected end-to-end distortion, accounting for both coding and packet-loss-induced distortions, as well as for the bursty nature of channel losses and the effective use of multiple transmission paths. With this model of end-to-end expected distortion, the encoder selects between MD coding modes in a rate-distortion optimized manner to most effectively trade-off compression efficiency for error resilience. We show how this approach adapts to the local characteristics of the video as well as to current network conditions and demonstrate the resulting gains in performance.