The Optimization of HEVC Intra Prediction Mode Selection

In order to reduce the computational complexity of the intra prediction module in HEVC, this paper proposes an optimization method for intra prediction mode selection. First, the size of the prediction block PU in HEVC is obtained. For 4×4 size PU block, the prewitt operator is used to extract the texture direction. Then, we judge whether the texture direction is obvious or not. If it is obvious, we use the angle mode corresponding to the texture direction and the modes of MPM to participate rate distortion calculation. If it is not obvious, we use mode 0, mode 1, the mode of minimum SATD and the modes of MPM to participate rate distortion calculation. For others size PU block, we use the most probable prediction mode MPM to filter the pre-selected list calculated by rough selection process. In this way, we can reduce the number of prediction modes participating rate distortion calculation. The experimental results shows that the proposed algorithm can reduce the encoding time by 32.42%, while the coding bit rate only increases by 0.25%, BDPSNR only reduces about 0.06dB. This algorithm meets the requirement of the complexity reduction and effectively reducing the encoding time.