Visual information fidelity based frame level rate control for H.265/HEVC

Abstract

Rate control in video coding seeks for various trade-off between bitrate and reconstruction quality, which is closely tied to image quality assessment. The widely used measurement of mean squared error (MSE) is inadequate in describing human visual characteristics, therefore, rate control algorithms based on MSE often fail to deliver optimal visual quality. To address this issue, we propose a frame level rate control algorithm based on a simplified version of visual information fidelity (VIF) as the quality assessment criterion to improve coding efficiency. Firstly, we simplify the VIF and establish its relationship with MSE, which reduce the computational complexity to make it possible for VIF to be used in video coding framework. Then we establish the relationship between VIF-based $\lambda$ and MSE-based $\lambda$ for $\lambda$-domain rate control including bit allocation and parameter adjustment. Moreover, using VIF-based $\lambda$ directly integrates VIF-based distortion into the MSE-based rate–distortion optimized coding framework. Experimental results demonstrate that the coding efficiency of the proposed method outperforms the default frame-level rate control algorithms under distortion metrics of PSNR, SSIM, and VMAF by 3.4$\text{\%}$, 4.0$\text{\%}$ and 3.3$\text{\%}$ in average. Furthermore, the proposed method reduces the quality fluctuation of the reconstructed video at high bitrate range and improves the bitrate accuracy under hierarchical configuration .