HEVC quantization parameter selection algorithm based on inter-frame dependency

Massive inter predictive modes are adopted in latest High Efficiency Video Coding (HEVC) standard to eliminate temporal redundancies, which results in stronger inter-frame dependency among neighboring frames than previous standards like H.264. The inter-frame dependency makes currently independent rate-distortion optimization (RDO) non-optimal any more. Quantization parameter (QP) selection algorithm taking inter-frame dependency into consideration is supposed to optimize RDO based rate control greatly. According to our research, the inter-frame dependency is reflected by the linear relationship between QP change (Delta QP) and the resulting change of distortion (Delta D). An adaptive QP selection algorithm for global RDO is proposed based on the modeling function between Delta D and Delta QP in this paper. Firstly, based on intensive statistic analysis, three parameters (initial QP (QP over bar \documentclass[12pt]{minimal} the length of pictures of group (GOP), and the average of SATD of one frame) are used to formulate the relationship between Delta D and Delta QP. Secondly, the resulting rate change Delta R relative to Delta QP is also formulated similarly. Thirdly, optimized Lagrangian multiplier (lambda) is calculated with these two mathematic models. Finally, we refine QP values based on the optimized lambda in terms of dependent RDO. The experimental results show that the proposed frame-level QP selection algorithm can decrease Bj circle divide tegaard Delta BitRate (BD-BR) by about 1.62% at the random-access (RA) configuration and 1.13% at the low-delay (LD) configuration, respectively. At the same time, it doesn't increase complexity significantly.