Research In Fast Mode Decision Algorithm For Intra Prediction In HEVC Video Coding

High Efficiency Video Coding (HEVC) is the next generation videocoding standard.35intra prediction modes are defined in HEVC toimprove coding efficiency. But so many modes result in the dramaticallyincreased encoding complexity. In this paper, a novel fast intra modedecision algorithm is proposed to speed up the original intra coding inHEVC. Different from previous algorithms, we analyzed the statisticsgenerated by rough mode decision (RMD) process which is adopted inHEVC. First, we found that the modes generated by RMD are usuallyadjacent to each other, thus representing roughly a same direction. Wemerged adjacent modes into same groups. Furthermore, early terminationand pixel-based edge detection methods are employed to make accurateprediction by heuristically reducing the number of candidates for ratedistortion optimization (RDO) process. Experimental results show that ourproposed fast intra mode decision algorithm can obtain almost23.52%time savings in all intra low complexity cases on average with negligibleperformance loss compared to the original HEVC intra coding in HM7.0.Meanwhile, the results are especially favorable when it comes to highresolution test sequences with up to0.4%bit-rate increment and21.81%time savings. Our algorithm could effectively reduce encoding time underresolution from416×240to2500×1600.