Multiple Video Frame Interpolation via Enhanced Deformable Separable Convolution

Generating non-existing frames from a consecutive video sequence has been an interesting and challenging problem in the video processing field. Recent kernel-based interpolation methods predict pixels with a single convolution process that convolves source frames with spatially adaptive local kernels. However, when scene motion is larger than the pre-defined kernel size, these methods are prone to yield less plausible results and they cannot directly generate a frame at an arbitrary temporal position because the learned kernels are tied to the midpoint in time between the input frames. In this paper, we try to solve these problems and propose a novel approach that we refer to as enhanced deformable separable convolution (EDSC) to estimate not only adaptive kernels, but also offsets, masks and biases to make the network obtain information from non-local neighborhood. During the learning process, different intermediate time step can be involved as a control variable by means of the coord-conv trick, allowing the estimated components to vary with different input temporal information. This makes our method capable to produce multiple in-between frames. Furthermore, we investigate the relationships between our method and other typical kernel- and flow-based methods. Experimental results show that our method performs favorably against the state-of-the-art methods across a broad range of datasets. Code will be publicly available on URL: \url{https://github.com/Xianhang/EDSC-pytorch}.