Spatial–Temporal Correlation Information-Based Rate Control for Versatile Video Coding

Although lambda-domain-based rate control is widely used in video encoders, developing an efficient rate control scheme for Coding Tree Units (CTUs) under the rate-distortion (R-D) principle remains a significant challenge. In this paper, we propose a spatial-temporal correlation information-based rate control scheme for Versatile Video Coding (VVC), aiming to improve coding performance. We introduce a weight estimation network to establish a CTU-level bit allocation strategy that fully exploits spatial-temporal contextual information. Moreover, the CTU-level coding parameter λ is adaptively optimized based on a dependency factor derived from distortion dependency information in both the spatial and temporal domains. Experimental results demonstrate that, compared to the default VVC rate control, the proposed scheme achieves BD-Rate savings of 6.48%, 17.33% and 13.75% in terms of the Peak Signal-to-Noise Ratio (PSNR), the Multi-Scale Structural Similarity Index (MS-SSIM) and the Video Multimethod Assessment Fusion (VMAF), respectively, under the Low Delay_P (LDP) configuration in the VVC Test Model (VTM) 19.0. Furthermore, the proposed method outperforms other state-of-the-art rate control schemes.