Pooled zero vector coding for enhanced compression of motion vectors

In this paper, we propose a pooled zero vector coding scheme for improving coding efficiency of moving pictures. Since motion vector takes considerable portion of compressed bitstream, its higher compression is very essential for improving the coding efficiency of moving pictures beyond that given by the state-of-the-art coder of H.264/AVC. Since there is considerable correlation among motion vectors of adjacent blocks, lots of macroblocks end up with all their blocks having zero residual motion vector after differential motion vector coding using their individual predicted motion vectors. Motivated by this observation, we develop a new macroblock coding mode of ldquopooled zero vector codingrdquo to efficiently represent such cases. Compared to the H.264/AVC standard with several well-known video test sequences, total bitrate saving of average 2.07% is reported.