An Unsymmetrical Diamond Search Algorithm for H.264/AVC Motion Estimation

The performance of motion estimation is of great importance for H.264 advanced video coding. It is estimated that motion estimation consumes about 70% of the encoding time. Lots of motion estimation algorithms are proposed to improve the encoding speed. Unlike the assumption of most motion estimation algorithms, the horizontal motion vectors are much larger than the vertical in most cases. With the unsymmetrical characteristic, this paper presents a new diamond search based motion estimation algorithm to improve the efficiency. The unsymmetrical diamond search shorten the vertical step to lower down the computation complexity. The search points of the big template and the small template are reduced to 5 and 3 respectively. The simulation results show that, the unsymmetrical diamond search can achieve much more significant speedup ratio than other motion estimation algorithms with relatively high probability.