In H.265/HEVC, the random-access prediction structure helps to increase the coding efficiency and provides the temporal scalability. However, the quantization parameter cascading (QPC) strategy being used is not optimized in terms of the rate-distortion performance. This paper analyzes the rate and distortion dependency between temporal layers, and proposes a PSNR metric-based distortion model and a piecewise rate model to optimize the QPC. Experimental results demonstrate that the proposed algorithm achieves an average APSNR gain of 0.12dB with the maximum APSNR gain being 0.37dB. Meanwhile, an up to 8.7% BD-rate reduction with the average BD-rate reduction being 3.3% can be obtained.
['Yuan Yang', 'Shuai Wan', 'Yanchao Gong', 'Kaifang Yang']
Adaptive quantization parameter cascading for random-access prediction in H.265/HEVC based on dependent R-D models