Context-adaptive fast motion estimation of HEVC

High Efficient Video Coding (HEVC) is the latest coding standard with superior compression efficiency while its encoding complexity is much higher compared with H.264/AVC. Motion estimation is one of the most time-consuming parts in video coding. In the reference software of HEVC, TZ (Test Zone) search method is adopted as the fast motion estimation method. However, its complexity is still high. There are many other fast motion estimation methods, for example, the hexagon search method, but their performance loss is larger than TZ search. In order to balance coding speed and performance, a new context-adaptive fast motion estimation algorithm is proposed in this paper. In this the proposed, motion intensity is defined in block-level, motion vectors and motion vector differences of neighbor blocks are utilized to measure the motion intensity. When motion intensity is large, TZ search method is used; otherwise, hexagon search method is used. Experimental results show that the proposed method can save 39% ~ 60% of motion estimation time with average 0.5% of BD-rate loss.