CTU-Level Rate Control with λ Optimization Based on Visual Gaze Mechanism for 360-Degree Versatile Video Coding

Understanding the human visual gaze mechanism is crucial for enhancing 360° video coding technology. This paper presents a Coding Tree Unit (CTU)-level rate control scheme with λ optimization strategy for 360° Versatile Video Coding (VVC), with the aim of enhancing rate-distortion performance and bitrate accuracy. Specifically, the Lagrange parameter λ is optimized with consideration of distortion dependency and the identification of key CTUs guided by visual gaze, which are derived from a 360° video path generation network, thoroughly integrating the characteristics of the human visual gaze. Experimental results show that the proposed scheme achieves BD-rate savings in terms of Weighted to Spherically uniform-Peak Signal-to-Noise Ratio (WS-PSNR) and Sphere-Peak Signal-to-Noise Ratio (S-PSNR) across various coding configurations.