Fast motion estimation algorithm using unequal search effort for H.264|MPEG-4 AVC encoder

H.264IMPEG-4 AVC allows multiple reference frames and multiple partition types to improve the coding performance at the expense of much higher computation complexity. This paper proposes a fast motion estimation (ME) algorithm to reduce search complexity for this demanding configuration. Our experimental results show that the partition type which gives the lowest matching cost for the reference frame closest to the current picture in temporal domain is likely to be the best partition type for all reference frames. Based on this finding, the proposed method performs a less complicated search effort for the other partition types on the remaining reference frames to obtain significant savings in search complexity. This approach can be easily modified to support any existing fast search algorithms. Simulation results show the proposed algorithm significantly reduces the overall motion search complexity and at the same time, maintains minimum coding performance degradation.