A horizontal data reuse approach for fractional motion estimation in H.264/AVC encoder

Fractional Motion Estimation (FME) with quarter-pixel accuracy improves the video encoding efficiency significantly. The 6-tap 2-D FIR of half-pixel interpolation requires redundant access to search window SRAMs. Since the size of search window SRAMs is relatively large, the redundant access causes much extra power consumption. In previous works, the vertical data reuse was fully achieved, while the horizontal data reuse was not. In this brief, a horizontal data buffering approach is proposed to improve the horizontal data reuse. Through this approach, the reduction of access to the reference pixel SRAMs for FME of a macro-block is 45% for inter-modes with sub block size of 16×16 and 16×8, and 30% for inter-modes with sub block size of 8×16, 8×8 and 8×4. The reduction of dynamic power consumption caused by memory access is proportional to the reduction in memory access. The hardware overhead of this proposed approach is 5.62k gates, only 2.6% of the overall hardware cost.