Rate-Distortion-Optimization-Based Quantization Parameter Cascading Technique for Random-Access Configuration in H.265/HEVC

The random-access configuration is employed in H.265/HEVC video coding to make inter-frame prediction more efficient. The coding efficiency under the random-access configuration is closely related to the quantization parameter cascading (QPC) technique which determines the QP for encoding pictures in different temporal layers. The present QPC technique for the random-access configuration in H.265/HEVC is not optimized. In this paper, first, a rate-distortion-optimization-based technique for QPC, referred to as RDO-QPC, is proposed for the random-access configuration in H.265/HEVC. Based on the results from RDO-QPC, a simplified QPC technique, referred to as SRDO-QPC, is proposed. The experimental results verify the efficiency of the proposed two QPC techniques. Compared with the original configuration of QPC in H.265/HEVC, RDO-QPC achieves an average gain of 0.19 dB in APSNR and an average reduction of 4.87% in ABR, while SRDO-QPC achieves an average gain of 0.17 dB in APSNR and an average reduction of 4.32% in ABR. These two QPC techniques can both be used in practical situations, meeting different requirements of computational complexity.