| Summary: | 碩士 === 國立中正大學 === 資訊工程所 === 93 === In this study, a H.264 video compression video bitstream is transformed into transmission video packets by frame interleaving and FMO function enabling, which are transmitted from the encoder to the decoder. Bursty errors in one/consecutive transmission video packet(s) will be distributed into different video frames (slices or blocks) so that the synchronization problem can be solved easily.
In the proposed scheme, corrupted transmission packets are detected under the decoding procedure. After all the corrupted slices (block) within transmission video packets are detected by the proposed error detection scheme, the proposed error concealment scheme is used to conceal all the corrupted video blocks. In this study, the proposed error concealment scheme for I frames using pixel interpolation and the fast BNM algorithm is used to conceal I frames. In inter-coded P frames, the optimal candidate concealed block for a corrupted block is searched over all the motion-compensated by all available spatial and temporal information. First, the PMV for a corrupted block is determined by the spatial MVs around the corrupted block and the corresponding “temporally neighboring” MVs in the previous reference frame, whose motion-compensated blocks overlap the corrupted block. To speed up the optimal candidate conceal block search process, three kinds of rood search patterns in the previous reference frame, namely, 5-, 8-, and 12-point rood search patterns, for determing the optimal MV are proposed for small-, medium-, and large-motion blocks, respectively. After all the corrupted blocks in a P frame are initially concealed by temporal motion-compensated concealment, error concealment refinement is performed by all the concealed blocks to improve the error concealment results. A new fitness function using the proposed DBME for error concealment is also proposed.
Based on the simulation results obtained in this study, the performance of the proposed scheme is better than that of the corresponding comparison schemes. Additionally, the proposed scheme can be easily employed in several existing network environments and applicable to many other block-based image/video compression standards, such as MPEG-2, H.263 and MPEG-4, with some necessary modifications. This shows the feasibility of the proposed scheme.
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