Matching Pursuits Multiple Description Coding for Wireless Video.pdf

Matching Pursuits Multiple Description Coding for Wireless Video Xiaoyi Tang and Avideh Zakhor Abstract Multiple description coding (MDC) is an error resilient source coding scheme that creates multiple bitstreams of approximately equal importance. The reconstructed signal based on any single bitstream has an acceptable quality. However, a higher quality reconstruction can be achieved with larger number of bitstreams. We develop a multiple (2) description video coding scheme based on the 3 loop structure originally proposed in [1]. We modify the discrete cosine transform structure to the matching pursuits frame- work and evaluate performance gain using maximum likeli- hood (ML) enhancement when both descriptions are avail- able. We find that ML enhancement works best for low mo- tion sequences and results in gains of up to 1.3 dB in terms of average PSNR. Rate distortion performance is character- ized. Performance comparison is made between our MDC scheme and single description coding (SDC) schemes over lossy channels, including two state Markov channels and Rayleigh fading channels. We find that MDC outperforms SDC in bursty slowly varying environments. In the case of Rayleigh fading channels, interleaving helps SDC close the gap and even outperform MDC depending on the amount of interleaving performed, at the expense of additional de- lay. I. Introduction Multiple description coding (MDC) generates multiple encoded bitstreams of a source and sends them through several independent channels. The source can be recon- structed at a lower yet acceptable quality from any single bitstream, and at a higher quality from more bitstreams. Unlike layered coding which requires correct reception of the base layer for enhancement layers to be useful, MDC can reconstruct the source from any subset of bitstreams. MDC provides a robust source coding scheme for commu- nication over unreliable channels without quality-of-service (QoS) guarantee. Early work on MDC was focused on theor