A video communication system based on combined source-channelcoding is proposed. The proposed system uses a hybrid subband videocoder structure in combination with power-constrained channel-optimizedvector quantization (PCCOVQ) to achieve efficient and robusttransmission of the video signal over a channel with multidimensionalPAM signaling. The error-sensitive side information parameters areprotected by using traditional channel coding and a sufficiently largeminimum distance of the PAM signal constellation. This ensures errorfree transmission for the channel-optimized case, and gracefuldegradation for channel mismatch situations. For the main information,PCCOVQ with a direct mapping from the source parameter space to thechannel (modulation) space is used. A traditional video communicationsystem based on the H.263 video coder is used as a reference. Theproposed system compares favorably to the reference system for high rateapplications, and offers graceful degradation for channel mismatchsituations
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