Multiframe video coding for improved performance over wireless channels

In this paper, we propose and evaluate a multiframe extension to block moti on compensation (BMC) coding of,videoconferencing-type video signals for wi reless channels. The multiframe BMC (SF-BMC) coder makes use of the redunda ncy that exists across multiple frames in typical videoconferencing sequenc es to achieve additional compression over that obtained by using the single frame BMC (SF-BMC) approach, such as in the base-level H.263 codec, The MF -BMC approach also has an inherent ability of overcoming some transmission errors and is thus more robust when compared to the SF-BMC approach. We mod el the error propagation process in MF-BMC coding as a multiple Markov chai n and use Markov chain analysis to infer that the use of multiple frames in motion compensation increases robustness, The Markov chain analysis is als o used to devise a simple scheme which randomizes the selection of the fram e (amongst the multiple previous frames) used in BMC to achieve additional robustness. The MF-BMC coders proposed in this paper are a multiframe extension of the base level H.263 coder and are found to be more robust than the base level H.263 coder when subjected to simulated errors commonly encountered on wire less channels.