In this paper we propose an error control scheme for video communications over lossy channels. The proposed algorithm uses stochastic frame buffers(SFB) to determine the expected decoder error by using channel simulated frames during motion vector(MV) and reference frame search, macroblock(MB) mode decisions and residual selection. Unlike previous methods, our algorithm also focuses on optimizing the MV and prediction frame selection and residual selection over error prone channels. The algorithm minimizes a Lagrangian to achieve the optimal result for mode and MVs. If there is channel feedback, the system can utilize it to update the SFB. We perform experiments that compare our system with intra refreshes, an improved NEWPRED and optimal mode switching algorithms such as ROPE under various conditions such as existence of a feedback channel or not. We show that the proposed system outperforms others.
Oztan Harmanci, A. Murat Tekalp