A recursive shape error concealment algorithm

The encoding of shape information is a distinguishing feature of MPEG-4. In error prone communication networks, it is important and efficient to conceal shape errors spatially, so as to avoid propagation of errors in the video frames. The proposed system first defines the missing area's four rectangular neighbors. It then detects in the neighbors the lines that intersect the borders and redefines them in a geometric coordinate system. These lines are paired under some optimization objective so that they connect smoothly in the missing area. Each pair is extrapolated and corrected recursively until a close curve is formed. Test results on various sequences under various error rates are presented and compared with other shape concealment methods.