A Fast Sub-Pixel Motion Estimation Algorithm for H.264/AVC Video Coding

摘要

Motion Estimation (ME) is one of the most time-consuming parts in videocoding. The use of multiple partition sizes in H.264/AVC makes it even morecomplicated when compared to ME in conventional video coding standards. It isimportant to develop fast and effective sub-pixel ME algorithms since (a) Thecomputation overhead by sub-pixel ME has become relatively significant whilethe complexity of integer-pixel search has been greatly reduced by fastalgorithms, and (b) Reducing sub-pixel search points can greatly save thecomputation for sub-pixel interpolation. In this paper, a novel fast sub-pixelME algorithm is proposed which performs a 'rough' sub-pixel search before thepartition selection, and performs a 'precise' sub-pixel search for the bestpartition. By reducing the searching load for the large number of non-bestpartitions, the computation complexity for sub-pixel search can be greatlydecreased. Experimental results show that our method can reduce the sub-pixelsearch points by more than 50% compared to existing fast sub-pixel ME methodswith negligible quality degradation.