Fast motion estimation and Inter-mode decision for H.264/MPEG-4 AVC encoding

Abstract

In H.264/MPEG-4 AVC encoding, computational complexity is the main concern for implementation and application. Motion estimation (ME) and Inter-mode decision (MD) consume a large portion of encoder computation power. ME is referred to the process to find the motion vector (MV) for a block, and MD is referred to the process to determine the best block-size for Inter-frame prediction. This paper proposes a new concept of introducing diversity into the MV search strategy. Based on the diversity concept, we introduce a new fast ME search strategy: adaptive diversity search strategy (ADSS), by combining the strength of different search strategies. We also investigate three fast ME strategies by MV merging and splitting for variable-size block motion estimation (VSBME), which explores the correlation of MVs of overlapping blocks. In addition, an Inter-mode decision is proposed by fast mode exclusion (FME). The experiment results show that the proposed fast ME can reduce the search points to about 4% of that by full search, and that the proposed FME can reduce the computation further, with negligible degradation in the rate-distortion (R-D) performance.