Joint Source/FEC Rate Selection for Optimal MPEG-2 Video Delivery

This paper deals with the optimal allocation of MPEG-2 encoding and media-independent FEC rates under a total given bandwidth. The optimality is defined in terms of minimum perceptual end-to-end distortion given a set of video and network parameters. We first derive the set of equations leading to the residual loss process parameters. That is, the packet loss ratio and the average burst length after FEC decoding. We then show that the perceptual source distortion decreases exponentially with the MPEG-2 source rate. We also demonstrate that the perceptual distortion due to data lossis directly proportional to the number of lost macroblocks, and therefore decreases with the amount of channel protection. Finally, we derive the global set of equations that lead to the optimal dynamic rate allocation. The optimal distribution is shown to outperform classical FEC schemes, thanks to its adaptivity to the scene complexity, to the available bandwidth and to the network conditions.