  We present a method to edit a target portrait footage by taking a sequence of
audio as input to synthesize a photo-realistic video. This method is unique
because it is highly dynamic. It does not assume a person-specific rendering
network yet capable of translating arbitrary source audio into arbitrary video
output. Instead of learning a highly heterogeneous and nonlinear mapping from
audio to the video directly, we first factorize each target video frame into
orthogonal parameter spaces, i.e., expression, geometry, and pose, via
monocular 3D face reconstruction. Next, a recurrent network is introduced to
translate source audio into expression parameters that are primarily related to
the audio content. The audio-translated expression parameters are then used to
synthesize a photo-realistic human subject in each video frame, with the
movement of the mouth regions precisely mapped to the source audio. The
geometry and pose parameters of the target human portrait are retained,
therefore preserving the context of the original video footage. Finally, we
introduce a novel video rendering network and a dynamic programming method to
construct a temporally coherent and photo-realistic video. Extensive
experiments demonstrate the superiority of our method over existing approaches.
Our method is end-to-end learnable and robust to voice variations in the source
audio.
