Low Complexity Inter-Mode Selection for H.264

The coding efficiency of the H.264/AVC standard enables the transmission of high quality video over bandwidth limited networks. Due to the use of multiple macroblock (MB) partitions, the motion estimation module has extremely high complexity that makes it unpractical for most real-time applications on resource-limited platforms such as hand held devices. In this paper we propose a novel algorithm that significantly reduces the encoding complexity while maintaining high rate distortion performance. The proposed method reduces the motion estimation (ME) computational complexity by accurately predicting the optimal MB partitions and restricting the number of candidate modes based on a-priori probabilities computed from spatio-temporal information. The experimental results show that the speed up of UmHexagonS (one of the most efficient ME algorithms) can be doubled while maintaining the coding efficiency of full search.