Coding of motion compensation residuals using edge information

In most current video coders, a block is first predicted from its best matching block in a previous frame, and the prediction error is then coded using discrete transform coding (DCT). Because of the inadequacy of the block-wise translational motion model, edges in the predicted block are often shifted from their true positions, leading to errors that are clustered around edges in the predicted block. DCT is inefficient for coding such errors. Independent searching of block motion vectors also lead to discontinuities of edges across block boundaries. Existing coders ignore such correlation between error location and edge discontinuity. We describe a coder that corrects edge-misalignment before applying DCT coding. The correlation between edge-discontinuity and edge-misalignment is exploited in the coding of the misalignment parameters