| With the rapid growth of multimedia services, increasing demands on video transmission have driven numerate researchers to develop error resilient techniques. The perceptual video quality is influenced by not only compression artifacts, but also the channel errors. Hence, a desired video codec has to accommodate the contradictory requirements, which are coding efficiency, robustness to data loss as well as other limitations, such as memory, bandwidth and complexity.; In this work, we first presented unequal error protection schemes in multi-user and end-to-end systems. Fast searching algorithms have been proposed to significantly speed up the system optimization. Additionally, we have developed a simple rate-distortion model in terms of quantization parameter, so that the rate and the distortion can be estimated without an extensive encoding procedure. Secondly, two novel error concealment methods have been proposed for I-frames and frames, respectively. The I-frame error concealment method employs edge detection and directional interpolation. It can efficiently recover both smooth and edge areas, while demanding a low computational complexity. The P-frame error concealment method uses error tracking and dynamic mode weighting. It is able to not only better compensate the corrupted macroblocks, but also suppress the propagation errors. Thirdly, we have investigated the error propagation effect in the multi-hypothesis motion compensated prediction (MHMCP) coder and analyzed the rate-distortion performance in terms of the hypothesis number and hypothesis coefficients. Adaptive MHMCP codecs have been designed to further enhance the rate distortion performance. Additionally, we have compared the performance of MHMCP with other error resilient tools, and shown that MHN4CP suppresses the short-term effect of error propagation more effectively than the intra-refreshing scheme. Finally, several design principles for the MHMCP coder are derived based on the analytical and experimental results. |
