Joint Source-Channel Rate-Distortion Optimization for Wireless Video Transmission

This paper proposes a joint source-channel rate-distortion (RD) optimization for real-time video transmission. The video compression and forward error correction (FEC) options are optimized by looking for the best trade-off between the estimated end-to-end distortion of a video packet and the sum of the number of source bits and FEC bits used to encode that packet. Video coding options include coding mode and quantization parameter, which are selected for each macroblock. Channel coding options consist of different FEC code rates that provide different levels of protection against the lossy channel. The proposed RD technique adjusts the bit rate to meet a target using a Lagrange multiplier approach. The encoder also uses the instantaneous channel state information to improve performance for a varying channel. Conventional RD optimization approaches optimize over the video coding modes, and our approach which considers the channel and FEC bits as well has better performance over both AWGN and Rayleigh fading channels. We also consider an approach to reduce the computational complexity of the proposed RD scheme.