Dual block simultaneous search for fast hierarchical motion estimation

The paper presents a fast algorithm for 2-layer hierarchical motion estimation suitable to software video encoders. Reduction of computational complexity has been achieved by estimating motion in the lower resolution layer for two-macroblock sets, as opposed to estimating it separately for each individual macroblock. This results in faster motion estimation with only negligible degradation in video quality. Degradation in PSNR was only 0.1 dB at 4 Mbps for MPEG-2, and computational complexity was reduced by 40% as compared with conventional 2-layer estimation. It also makes it possible to improve PSNR by 0.9 dB with only 30% greater computational complexity, as compared with a conventional three step search algorithm.