Efficient bit allocation and CTU level rate control for High Efficiency Video Coding

In this work, a CTU level rate control algorithm is proposed for High Efficiency Video Coding (HEVC). On top of the CTU level rate control algorithm, an efficient bit allocation method considering the HEVC hierarchical coding structure is specifically designed. Instead of directly applying the rate distortion model at the CTU level, it´s proposed to derive the CTU level quantization parameter (QP) based on the frame level QP with feedback of the coding status of CTUs. To further improve the coding performance of the CTU level rate control, a QP adjustment strategy is proposed and incorporated into the rate control algorithm. Experimental results show that the proposed CTU level rate control algorithm can achieve better coding performance than the state-of-the-art rate control scheme for HEVC (1.9% for RA, 3.2% for LD). Moreover, the coding quality become much smoother with the proposed algorithm.