A fast full search algorithm for variable mock-based motion estimation of H.264

Abstract

In this paper, we propose a novel fast motion estimation algorithm based on successive elimination algorithm (SEA) which can dramatically reduce complexity of the variable block size motion estimation in H.264 encoder. The proposed method applies the conventional SEA in the hierarchical manner to the seven block modes. That is, the proposed algorithm can remove the unnecessary computation of SAD by means of the process that the previous minimum SAD is compared to a current bound value which is obtained by accumulating current sum norms and reused SAD of 4x4 blocks for the bigger block sizes than 4x4. As a result, we have tighter bound in the inequality between SAD and sum norm than the bound in the ordinary SEA. If the basic size of the block is smaller than 4x4, the bound will become tighter but it also causes to increase computational complexity, especially addition operations for sum norm. Compared with fast full search algorithm of JM of H.264, our algorithm saves 60 to 70% of computation on average for several image sequences.