A context-adaptive fast intra coding algorithm of high-efficiency video coding (HEVC)

This paper proposes a context-adaptive fast intra coding algorithm of high efficiency video coding (HEVC). Intra coding of HEVC improves the coding efficiency of intra coded picture with an exhaustive computation and evaluation. In this paper, the proposed algorithm consists of an adaptive rough mode selection to decrease the prediction modes for rough mode decision (RMD), based on the upper coding unit (CU) and the neighboring prediction units (PU), by minimizing BD-rate increment and encoding complexity. For further complexity reduction, the early termination approaches for RDO and RQT stages are also introduced by the adaptive thresholding based on the average value of rate distortion (RD) costs. In terms of complexity evaluation, experimental results show that the proposed algorithms reduce encoding time at about 40% with 1.3% BD-rate loss on average, compared to the reference software of HEVC.