H.264 inter-frame sub-block mode and intra-frame mode selection algorithm

Since H.264 inter-frame encoding with multi-size sub-block modes and intra-frame encoding with multi-mode involved much calculation, a novel algorithm for H.264 inter-frame sub-block mode selection and intra-frame mode selection based on statistic threshold was proposed. Scale of all the modes was restricted via statistic threshold. Simulation experiment results from video sequences show that the encoding time of I frame decreases by 17% to 23% and PSNR decreases less than 0.4%. The encoding time of P frame was reduced by 20% to 30% contrasted with that of all sub-block modes. This algorithm is effective in enhancing encoding speed with PSNR lower 0.047dB at most.