About HEVC Fast Intra Prediction Mode Selection Algorithm

High Efficiency Video Coding (HEVC) is the next generation video coding standard, jointly developed by ISO/IEC and ITU-T with the aim to improve the efficiency of video compression significantly. Compared to the existing standard H.264/AVC, HEVC can reduce about50%bit-rate for equal perceptual video quality. The nine kinds of intra-prediction direction in H.264are increased to35kinds in HEVC, so its prediction accuracy is higher than before. But so many modes result in the dramatically increased encoding complexity. Therefore, how to reduce video encoding complexity has become a hot research of video coding. This thesis mainly investigate the intra-prediction algorithm in HEVC, the main contents are as follows:1) For a large number of modes in Rough Mode Decision (RMD) and Rate Distortion Optimization (RDO) process, firstly, analyzing the texture characteristics of the reference pixels, and then exploit the correlation of the optimal modes in RMD with the optimal mode of current block, this thesis propose a fast mode decision algorithm; Finally, the algorithm is verified by simulation. The simulation results show that, compared to the test model HM10.0of HEVC, the average encoding time can be reduced by8.71%to36.61%with negligible performance loss.2) For the distribution structure of angle modes in HEVC, firstly, using a ring to represent these modes, this structure is more conducive to clarify the correlation between the angle mode, and then exploit the correlation of Most Probable Modes (MPM) with the optimal modes in RMD, propose a fast mode decision algorithm based on the cost of MPM; Finally, the algorithm is verified by simulation. The simulation results show that, compared to the test model HM10.0of HEVC, the average encoding time can be reduced by29.96%to33.51%with negligible performance loss.