Block Motion Estimation Using Directional Adaptive Search Window with Early Termination

Motion estimation (ME) is an important part of H.264 and other video compression standards, which eliminates temporal redundancies at the expense of higher computational complexity. Many adaptive methods have been proposed to reduce the amount of computation involved in ME. In this paper, two improvements are added to the technique using Directional Adaptive Search Window (DASW) method: Directional search process and Early termination. DASW alone can achieve a savings in number of search point computations of between 42% to 60%. By introducing Early Termination(ET) into motion estimation using DASW, the number of computations could be reduced even further since the search process is terminated immediately if the block is considered as a stationary block. However, DASW-ET incurs a slight degradation of less than 1dB, in PSNR performance.