Video Frame Interpolation and Enhancement via Pyramid Recurrent Framework.

Video frame interpolation aims to improve users' watching experiences by generating high-frame-rate videos from low-frame-rate ones. Existing approaches typically focus on synthesizing intermediate frames using high-quality reference images. However, the captured reference frames may suffer from inevitable spatial degradations such as motion blur, sensor noise, etc. Few studies have approached the joint video enhancement problem, namely synthesizing high-frame-rate and high-quality results from low-frame-rate degraded inputs. In this paper, we propose a unified optimization framework for video frame interpolation with spatial degradations. Specifically, we develop a frame interpolation module with a pyramid structure to cyclically synthesize high-quality intermediate frames. The pyramid module features adjustable spatial receptive field and temporal scope, thus contributing to controllable computational complexity and restoration ability. Besides, we propose an inter-pyramid recurrent module to connect sequential models to exploit the temporal relationship. The pyramid module integrates the recurrent module, thus can iteratively synthesize temporally smooth results. And the pyramid modules share weights across iterations, thus it does not expand the model's parameter size. Our model can be generalized to several applications such as up-converting the frame rate of videos with motion blur, reducing compression artifacts, and jointly super-resolving low-resolution videos. Extensive experimental results demonstrate that our method performs favorably against state-of-the-art methods on various video frame interpolation and enhancement tasks.