| Summary: | 碩士 === 國立成功大學 === 電腦與通信工程研究所 === 93 === Two error concealment schemes Weighted Pixel Value Averaging (WPVA) and Boundary Matching Based Motion Vector Recovery (BMBMVR), which are adopt by H.264/AVC, are used to conceal erroneous MacroBlocks (MBs) in intra pictures and inter pictures, respectively. However, WPVA would blur edges so as to cause bad visional effects, and BMBMVR just recovers a motion vector for an entire MB, causing that the recovered motion vector is usually unsuitable for each sub-MBs of the erroneous MB due to the region-based motion compensation mechanism in H.264. To deal with the problem of WPVA, we propose Single Edge Reserving (SER), which detects whether MBs are on Single Edge by using image-analysis methods, and reserves them by using Directional Interpolation. Besides, to deal with the problem of BMBMVR, we propose Sub-MacroBlock-Wise Motion Vector Recovery (SMBWMVR), which recovers lost motion vectors for each sub-MB of the erroneous MB. Further, in order to enhance H.264 error resilience, we modify the Minima Mean Square Error Double-vector Motion Compensation (MMSE DMC) algorithm to adapt it into H.264. MMSE DMC provides good performance in the reduction of error propagation for moving regions, but not for static regions. To improve its performance for static regions, we modify its mode-weighting equation.
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