  The recent advances in deep learning have made it possible to generate
photo-realistic images by using neural networks and even to extrapolate video
frames from an input video clip. In this paper, for the sake of both furthering
this exploration and our own interest in a realistic application, we study
image-to-video translation and particularly focus on the videos of facial
expressions. This problem challenges the deep neural networks by another
temporal dimension comparing to the image-to-image translation. Moreover, its
single input image fails most existing video generation methods that rely on
recurrent models. We propose a user-controllable approach so as to generate
video clips of various lengths from a single face image. The lengths and types
of the expressions are controlled by users. To this end, we design a novel
neural network architecture that can incorporate the user input into its skip
connections and propose several improvements to the adversarial training method
for the neural network. Experiments and user studies verify the effectiveness
of our approach. Especially, we would like to highlight that even for the face
images in the wild (downloaded from the Web and the authors' own photos), our
model can generate high-quality facial expression videos of which about 50\%
are labeled as real by Amazon Mechanical Turk workers.
