An improved algorithm of fast motion estimation based on H.264

Motion Estimation (ME) is the most important and time consuming part of H.264 video encoding, it takes about 60%~80% of encoding time. To improve the encoding speed of the UMHexagonS algorithm in x264, an optimized algorithm is proposed in this paper on three aspects via the modified scheme of the threshold selection, early termination of condition and big hexagon search mode. The simulation experimentation shows that the proposed algorithms can save about 30% of search points with small video quality decline as that of UMHexagonS algorithm. And besides, as for calculation of SAD value, modified method of the COST_MV() function, reduce the numbers of unnecessary SAD calculations and save about 20% to 40% of the estimated time.