A Unified Pyramid Recurrent Network for Video Frame Interpolation

Flow-guided synthesis provides a common framework for frame interpolation, where optical flow is estimated to guide the synthesis of intermediate frames between consecutive inputs. In this paper, we present UPR-Net, a novel Unified Pyramid Recurrent Network for frame interpolation. Cast in a flexible pyramid framework, UPR-Net exploits lightweight recurrent modules for both bi-directional flow estimation and intermediate frame synthesis. At each pyramid level, it leverages estimated bi-directional flow to generate forward-warped representations for frame synthesis; across pyramid levels, it enables iterative refinement for both optical flow and intermediate frame. In particular, we show that our iterative synthesis strategy can significantly improve the robustness of frame interpolation on large motion cases. Despite being extremely lightweight (1.7M parameters), our base version of UPR-Net achieves excellent performance on a large range of benchmarks. Code and trained models of our UPR-Net series are available at: https://github.com/srcn-ivl/UPR-Net.

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Task Dataset Model Metric Name Metric Value Global Rank Result Benchmark
Video Frame Interpolation MSU Video Frame Interpolation UPR-Net LARGE PSNR 29.73 # 2
SSIM 0.951 # 2
VMAF 71.34 # 3
LPIPS 0.025 # 4
MS-SSIM 0.962 # 2
Video Frame Interpolation SNU-FILM (easy) UPR-Net LARGE PSNR 40.44 # 3
SSIM 0.9911 # 1
Video Frame Interpolation SNU-FILM (extreme) UPR-Net LARGE PSNR 25.63 # 4
SSIM 0.8641 # 4
Video Frame Interpolation SNU-FILM (hard) UPR-Net LARGE PSNR 30.86 # 5
SSIM 0.9377 # 4
Video Frame Interpolation SNU-FILM (medium) UPR-Net LARGE PSNR 36.29 # 3
SSIM 0.9801 # 2
Video Frame Interpolation UCF101 UPR-Net LARGE PSNR 35.47 # 2
SSIM 0.9700 # 4
Video Frame Interpolation Vimeo90K UPR-Net LARGE PSNR 36.42 # 4
SSIM 0.9815 # 3
Video Frame Interpolation X4K1000FPS UPR-Net large PSNR 30.68 # 6
SSIM 0.9086 # 5

Methods