Objective Quality Assessment of Full-Scene Resampling-based Coding for VVC Standard

The Versatile Video Coding (VVC) standard integrates advanced tools to improve coding efficiency, including Reference Picture Resampling (RPR). The latter enables dynamic spatial resolution adjustments without requiring the insertion of additional intra-coded frames. However, implementing per-frame adaptive resampling in hardware-based VVC encoders poses challenges, leading to potential visual artifacts, especially with frequent resolution changes within a single scene. Nevertheless, maintaining a constant resolution throughout an entire sequence may not always be optimal, as varying frame content could benefit from different coding resolutions. This paper explores Full-Scene Resampling-based Coding (FsRC), a hardware-friendly resampling coding method that dynamically adjusts spatial video resolution at scene transitions. We analyze scaling ratios of 1.5 and 2, resulting in sample count reductions of 56% and 75%, respectively, and measure the energy savings and the potential coding efficiency gains. Coding efficiency is evaluated through bitrate savings at equivalent objective metric, the assessed objective metrics including MS-SSIM, VMAF, and PSNR. An exhaustive search establishes the coding efficiency upper bound for FsRC by systematically testing all scaling ratios and selecting the optimal for each encoding, simulating ideal decision-making.