Multiple description coding of motion fields for robust video transmission
In many video-coding standards, the motion vector field is one of the most important data in the compressed bitstream, and its loss can lead to severe degradation in the decoded picture quality. We propose the multiple description motion coding (MDMC) algorithm to enhance the robustness of the motion vector field against transmission errors. In MDMC, the motion vector field is encoded into two descriptions, which are transmitted over distinct channels to the decoder. The decoder is designed to provide an acceptable quality prediction image, even if one of the descriptions is lost during the transmission. Moreover, the decoder can reconstruct a higher quality prediction image, when both the descriptions are received without error. A complete multiple description video coder, based on the MDMC, is implemented by modifying the syntax of the H.263 standard, and tested intensively in a realistic error-prone environment. It is shown that the proposed algorithm provides much better objective and subjective performances than the H.263 coder in the error-prone environment.