Block INTER mode decision for fast encoding of H.264

Abstract

The paper presents a fast block INTER mode decision algorithm to improve significantly the time efficiency of the encoder in H.264. It makes use of the spatial homogeneity of a video object's textures and the temporal stationarity characteristics inherent in video sequences. Specifically, the homogeneity decision of a block is based on edge information, and MB differencing is used to judge whether the MB is time-stationary. Based on the above analysis, only parts of inter prediction modes are chosen for RDO (rate distortion optimization) calculation. Experimental results show that the new scheme is able to achieve a reduction of 30% encoding time on average, with a negligible average PSNR loss of only 0.03 dB and a mere 0.6% bit rate increase compared with the original H.264 reference software.