A fast intra coding algorithm for HEVC

Abstract

High Efficiency Video Coding (HEVC) is the emerging video coding standard, which provides equivalent subjective quality with about 50% bit rate reduction compared to H.264/AVC High Profile. However, the improvement of coding efficiency is obtained at the expense of increased computational complexity. In this paper, a fast algorithm for HEVC intra coding is proposed. Firstly, a depth range prediction method by exploiting the correlation between the neighboring Coding Tree Units (CTUs) is proposed. Secondly, the rate distortion costs and Sum of Absolute Difference with Hadamard transform (HSAD) of recently encoded CUs are used to decide whether current CU will be further divided or not. Finally, only the intra prediction modes (IPMs) with lower precision are employed in the rough mode decision (RMD) and IPMs for rate distortion optimization (RDO) are reduced based on the correlation between neighboring CUs. Experimental results show that our proposed algorithm can achieve average 54% (up to 57%) encoding time saving while causing negligible RD performance loss (1.0% BD-rate increase on average) in All Intra High Efficiency test condition compared with HM 10.0.