An adaptive spatio-temporal perception aware quantization algorithm for AVS2

Abstract

Adaptive quantization proves to be an effective tool to improve coding performance. In this paper, we propose an adaptive spatiotemporal perception aware quantization algorithm to increase subjective coding performance. To measure the spatiotemporally perceptual redundancy, the perceptual complexity models are firstly established with spatial and temporal characteristics respectively. With the help of the models, the adaptive spatial and temporal quantization parameter (QP) offsets are then calculated for each coding tree unit (CTU), respectively. Finally, the perceptually optimal Lagrange multiplier of each CTU is determined with the spatial–temporal QP offset. Experimental results show that the proposed algorithm reduces 8.6% and 8.4% Bjontegaard-Delta Rate (BD-Rate) with Structural Similarity Index Metric (SSIM) in average over the second generation of Audio Video Coding Standard (AVS2) reference software RD17.0 in Low-Delay-P (LDP) and Random-Access (RA) configurations, respectively. The subjective assessment proves that the proposed algorithm can reduce the bitrates with the same subjective quality significantly.