Adaptive fast intra prediction for high efficiency video coding

In this paper, a fast intra prediction algorithm for High Efficiency Video Coding (HEVC) is proposed by adopting the mode correlation between adjacent coding units. The proposed approach is realized by two pieces. Firstly, the prediction mode and partition structure for the current coding unit will inherit its optimal prediction coding unit directly if the Structural Similarity (SSIM) between the adjacent coding units satisfies the threshold condition. Secondly, unless the first case occurs, a two-step rough mode decision with adaptive threshold method including Sum of Absolute Difference (SAD) and Sum of Absolute Hadamard Transformed Difference (SATD) criterions is used to accelerate intra mode decision process based on HEVC test Model (HM) encoder. Besides, the most probable mode (MPM) which refers to the optimal prediction mode of the coded left and upper Prediction Units (PUs) surrounding the current PU is also considered. Experimental results show that the proposed algorithm can save 30.18 % encoding time on average with negligible loss of coding efficiency compared with HM10.0. The complexity and the bitrate are reduced by 11.45 and 0.46 % respectively compared with coding tree pruning method.