1. Introduction
The goal of super-resolution (SR) is to generate a high-resolution (HR) image or video from its corresponding low-resolution (LR) image or video. SR is widely used in many fields ranging from medical imaging [7] to satellite imaging [2] and surveillance [38]. With the advances in the display technology, the video super-resolution (VSR) for LR videos are becoming more important as the ultra high definition televisions target 4K (3840×2160) and 8K resolution (7680×4320), but the contents that match such high resolution are still scarce.