Studying Of Error Concealment Techniques For MPEG-4 Digital Video

With the developing of video compression and encoding technology, a series ofinternational video compression standards come on one after the other, and the videomultimedia data are widely used in many fields. Especially after the issue of MPEG-4standard that makes features of efficiency, scalability, interaction and robustness, digitalvideo has been extended application areas from image storage and digital TV to networksand wireless channels. Congestion, packet lose and transmission error are the inherentproblems involved in the internet and wireless mobile video communication system. Thetechniques of error control and concealment is necessary to this video encoding anddecoding applications. Post-processing techniques can be applied in any circumstances,and don't depend on extra encoding information, so the error concealment bypost-processing is difficult and important to any applications.As beginning of the dissertation studying error concealment of MPEG-4 video, therecent national and international achievements of error processing about MPEG-4 digitalvideo are summarized. Next,Based on the analysis of MPEG-4 image errors, somemodified methods for error detection, which can find most of the errors, are broughtforward. Thirdly, the recent algorithms of spatial and temporal error concealment ontexture data are introduced and summarized, and a new algorithm of temporal errorconcealment concerning Inter4v coding mode is presented, by which the motion vectorsand coding mode can be rebuilt. The algorithm can achieve nice quality of recoveredimage and well suite for real time video decoding applications. In the adaptive errorconcealment method, the neighboring information is used to choose automatically aproper algorithm of spatial or temporal error concealment which will reconstruct lost data,the quality of rebuilt image can be improved greatly. Fourthly, some recent algorithmsfor error concealment of shape information are introduced, and by combining logicallysome of them the shape errors in data stream are successively concealed.