Computation reduction of H.264/AVC motion estimation by search range adjustment and partial cost evaluation
Jin-Su Jung, Dong-Uk Moon, Hyuk‐Jae Lee · 2008
Motion estimation accounts for more than eighty percent of the total computation of H.264/AVC standard video compression. Full search based motion estimation is widely used for hardware implementation of an H.264/AVC encoder because of its simplicity and regularity. However, it requires a large amount of computation because it searches for all pixel points in the search range. This paper proposes a new hardware implementation of motion estimation which is a full search based motion estimation, but it reduces the search range around the seed motion vector predicted from neighboring macroblocks. The search range is determined by the variance of neighboring motion vectors. Simulation results show that the search range is reduced to less than ten percent of the original search range while the increase of bit rate is marginal. The result of integer motion estimation (IME) is used for the reduction of the computation of fractional motion estimation (FME). When the block size from IME is 16×16, only eight 4×4 blocks are evaluated for the derivation of Sum of Absolute Difference (SAD) between the current block and the reference block in the search range. Simulations results show that the degradation of the rate distortion performance is negligible by the proposed partial evaluation while the computation reduction ranges from 27.8% to 47.1%.