For an entropy-coded video bitstream, a transmission error in a codeword will not only affect the underlying codeword but may also affect subsequent codewords, resulting in a great degradation of received video frames. In this study, a new hybrid error concealment scheme for H.264 video transmission is proposed. Here, pixel interpolation and the fast best neighborhood matching (BNM) algorithm are employed to conceal intra-coded I frames. For inter-coded P frames, the predicted motion vector (PMV) for a corrupted block is first determined by the spatial MVs around the corrupted block and the corresponding temporally motionprojected overlapping MVs in the previous frame. Then based on the PMV, the optimal candidate concealed block for a corrupted block is searched over all the motion-compensated blocks in the previous frame with their MVs being determined by all the available spatial and temporal information. After all the corrupted blocks in a P frame are initially concealed, error concealment refinement is performed on all the initial concealed blocks to improve the error concealment results. Based on the simulation results obtained in this study, the performance of the proposed scheme is better than that of the corresponding comparison schemes. Categories and Subject DescriptorsSee the ACM template, ACM classification scheme and add the appropriate descriptors here.

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At first, the paper introduces the basic principles of OFDM system. And then analyzes the structural characteristics of the chip DM642. Taking the design requirements of the system into account, the implementation method in which the main design of underwater image transmission system based on DM642 is accomplished, and the detail designs are given. At the same time, the paper mainly analyzes the address generation process of the frame memory. And then some of the key technologies of PCB designing are introduced. In the software section, the implementations of ODFM technology and algorithm of video compression on the DM642 are highlighted for a specific introduction. Keywords-OFDM; video transmission; H.264; DSP