Adaptive search range motion estimation algorithm for H.264/AVC

In this paper, a novel variable search range algorithm is proposed for the H.264/AVC. First we evaluate the influence on the bitrate and PSNR when the search range is set from a small range to a increasing wide range. The simulation shows interesting results that sometimes when the search range is set to a smaller search range it can achieve better result at both the bitrate and the PSNR comparing with the reference software with the fixed search range of 16x16. Furthermore, we find that how much the search range could be reduced to achieve an optimum search range have strong relation with the average of the frame motion vectors. Based on these simulation results a adaptive search range algorithm which estimate the most efficient search range from the previous frames with a adaptively search range adjustment method is proposed. Simulation results show that proposed algorithm could achieve the motion estimation by average 45% computation complexity compare with the reference software with equivalent PSNR and the bitrate results.