  Video blogs and selfies are popular social media formats, which are often
captured by wide-angle cameras to show human subjects and expanded background.
Unfortunately, due to perspective projection, faces near corners and edges
exhibit apparent distortions that stretch and squish the facial features,
resulting in poor video quality. In this work, we present a video warping
algorithm to correct these distortions. Our key idea is to apply stereographic
projection locally on the facial regions. We formulate a mesh warp problem
using spatial-temporal energy minimization and minimize background deformation
using a line-preservation term to maintain the straight edges in the
background. To address temporal coherency, we constrain the temporal smoothness
on the warping meshes and facial trajectories through the latent variables. For
performance evaluation, we develop a wide-angle video dataset with a wide range
of focal lengths. The user study shows that 83.9% of users prefer our algorithm
over other alternatives based on perspective projection.
