  Recent years have seen considerable research activities devoted to video
enhancement that simultaneously increases temporal frame rate and spatial
resolution. However, the existing methods either fail to explore the intrinsic
relationship between temporal and spatial information or lack flexibility in
the choice of final temporal/spatial resolution. In this work, we propose an
unconstrained space-time video super-resolution network, which can effectively
exploit space-time correlation to boost performance. Moreover, it has complete
freedom in adjusting the temporal frame rate and spatial resolution through the
use of the optical flow technique and a generalized pixelshuffle operation. Our
extensive experiments demonstrate that the proposed method not only outperforms
the state-of-the-art, but also requires far fewer parameters and less running
time.
