Distortion-optimal receiver grouping for MD-FEC coded video streaming

Multiple Description with Forward Error Correction (MD-FEC) coding provides the flexibility, easy adaptivity and distortion-rate optimality that are desirable for delivering streaming video in a network environment with time-varying bandwidth fluctuations and random packet losses. In this paper, we consider the issue of how diverse receivers of a video stream should be grouped - where each group receives a MD-FEC coded bitstream optimized for that group - so that the average video distortion is minimized across all receivers. We show that a sequential grouping solution is optimal for linear distortion-rate functions. For non-linear distortion-rate functions, while the optimal grouping structure may not be sequential in general, we observe that the approximation factor attained by the best sequential solution can be characterized in terms of the “degree of convexity” of the distortion-rate function. Numerical experiments with realistic distortion-rate functions reveal that the difference between the globally optimal grouping solution and the best sequential solution, is typically small. We provide a dynamic programming based polynomial-time algorithm to compute the best sequential solution.