Fast intra mode decision for HEVC intra coding

This paper proposes an adaptive intra mode selection algorithm with rough mode decision (RMD) stage and an early termination for rate-distortion optimization (RDO) stage for fast intra coding of High Efficiency Video Coding (HEVC). The proposed adaptive mode selection for fast intra coding employs the prediction modes from the upper layer of coding unit (CU) and neighboring prediction units (PUs) to minimize BD-rate increment with the reduced candidate modes. In addition, the proposed early termination approach for RDO stage skips some candidate modes based on the average value of rate-distortion (RD) costs that are calculated from the RMD stage. Experimental results show that the proposed approaches reduce 28% of total encoding time with 1.7% BD-rate increment, compared to the reference software of HEVC.