Saliency-based coding tree unit-level rate control for high-efficiency video coding

Visual saliency is used to guide the coding tree unit (CTU)-level bit allocation process in high-efficiency video coding (HEVC) to improve the visual quality. At first, a saliency detection algorithm is proposed. With the detected saliency map, the distortion of each CTU is weighted by the corresponding saliency, so that the distortion of the salient areas (SAs) is more critical. Then, the optimal bit allocation problem constrained by the picture-level target bits and minimum weighted distortion is built. Numerical method is used to solve the bit allocation problem. Finally, bits reallocation and the rate distortion optimization parameters clipping methods are presented to tackle the bits error accumulation problem. Experiment results show that quality gaining in SAs is up to 0.8658 dB and the gaining of saliency weighted peak signal-to-noise ratio is up to 1.0318 dB.