We introduce a method to improve performance of multiple-description coding based on legacy video coders with pre- and postprocessing. The pre- and post-processing setup is general, making the method applicable to most legacy coders. For the case of two coders, a relative displacement of the intra-coding mode between the coders is shown to give improved robustness to packet loss. The optimal displacement of the intra-coding mode is found analytically, using a distortion minimization formulation where two independent Gilbert channels are assumed. The analytical results are con rmed by simulations. Tests with an H.263 coder show signi cant improvement in YPSNR over equivalent systems with no relative displacement of the intra-coding operation.
Ermin Kozica, Dave Zachariah, W. Bastiaan Kleijn