Motion estimation algorithm based on adaptive search range adjustment for H.264

To reduce the computational complexity and memory access bandwidth of motion estimation in H.264 video code, an algorithm to decide the search range for motion estimation is proposed. Firstly, the Search Range (SR) is adaptively selected based on the accuracy of Predicted Motion Vector (PMV), which is measured by using the Sum of Absolute Difference (SAD) of neighboring blocks. Then, the motion activity of coding region is also considered for search direction selection in the search area. The extensive experimental results show that the proposed algorithm is able to reduce 91% and 18% of the computation time on average compared to full search and UMHexagon algorithm, respectively, with almost the same bit rate and PSNR.