Patent ID: 7787542

Claim:
An encoder for encoding an image with selectively filtering a boundary between two adjacent blocks in a reconstructed image, comprising: motion compensation predictor for conducting motion compensation prediction for each of blocks to be encoded by using the reconstructed image, and transformer for transforming data of the block to be encoded, wherein filtering is not conducted for the boundary when (1) both the two adjacent blocks are predicted from a reference frame; (2) both the two adjacent blocks do not include any non-zero transform coefficients; and (3) motion vectors of the two adjacent blocks satisfy a specified condition, said specified condition including: |V(j,x)−V(k,x)|<1 pixel and |V(j,y)−V(k,y)|<1 pixel, where j and k are block numbers of adjacent blocks, V(j,x) and V(j,y) are components of the motion vector for block j, V(k,x), and V(k,y) are components of the motion vector for block k, x indicates horizontal direction of the motion vectors and y indicates vertical direction of the motion vectors.