A Fast Intra 4×4 Mode Decision Algorithm in H.264/AVC

H.264/AVC employs rate-distortion optimization (RDO) technique to select intra and inter prediction modes to achieve better coding efficiency at the cost of high computational complexity. To reduce the computational complexity of intra prediction, a fast intra 4×4 mode decision algorithm is proposed in this paper. We define a cost function FMPS, which uses three features: Previous Co-block Mode (PBM), Most Probable Mode (MPM) and the sum of absolute residual coefficients (SATD). Then several thresholds are given to determine the candidate prediction modes. Experimental results show that the proposed algorithm can reduce about 77% of the total encoding time without significant coding performance loss compared to the full search algorithm in JM 16.1.