An Optimized Algorithm at CTU-level for Rate Control
Zeng Li, Ruidong Fang, Zheng-Teng Zhang, Yuhan Cai, Yapeng Du, Jucai Lin, Jun Yin · 2021
CTU-level bit allocation in the High Efficiency Video Coding (HEVC) standard does not fully consider the texture characteristics of related CTUs. In order to solve this problem, this paper proposed a CTU-level algorithm for rate control. Firstly, the partition of current CTU is determined by the depth of the spatially co-located CTU in the latest frame. Secondly, the weight of target bitrate for each CTU will be improved according to the ratio of complex and flat blocks in the subCUs, which is obtained by the partition. In addition, considering the texture characteristics of different blocks in current CTU, this paper also adjusts the QP value of each coding unit (CU) according to the bit per pixel (bpp) and SATD per pixel (spp). The experimental results show that compared with the CTU-level rate control algorithm in the test model HM16.20, the error rate of the proposed algorithm in the LDP, LDB, and RA configuration is reduced by 0.72%, 0.74%, and 2.33%, respectively. And the subjective quality of the videos are improved while the volatility of rate is basically unchanged.