An inter block mode decision method based on gradient and RDO

This paper proposes a novel method of Inter-block mode decision based on gradient and RDO (Rate Distortion Optimizing) in H.264. The new method eliminates some rarely-possible modes according to the gradient distribution, which helps to reduce the number of candidate modes during the following RDO procedure. The experiments proves that this method saves about 80% time and the Y-PSNR drop is less than 2dB, compared with the traditional methods that goes through all modes.