  The ability to specify robot commands by a non-expert user is critical for
building generalist agents capable of solving a large variety of tasks. One
convenient way to specify the intended robot goal is by a video of a person
demonstrating the target task. While prior work typically aims to imitate human
demonstrations performed in robot environments, here we focus on a more
realistic and challenging setup with demonstrations recorded in natural and
diverse human environments. We propose Video-conditioned Policy learning (ViP),
a data-driven approach that maps human demonstrations of previously unseen
tasks to robot manipulation skills. To this end, we learn our policy to
generate appropriate actions given current scene observations and a video of
the target task. To encourage generalization to new tasks, we avoid particular
tasks during training and learn our policy from unlabelled robot trajectories
and corresponding robot videos. Both robot and human videos in our framework
are represented by video embeddings pre-trained for human action recognition.
At test time we first translate human videos to robot videos in the common
video embedding space, and then use resulting embeddings to condition our
policies. Notably, our approach enables robot control by human demonstrations
in a zero-shot manner, i.e., without using robot trajectories paired with human
instructions during training. We validate our approach on a set of challenging
multi-task robot manipulation environments and outperform state of the art. Our
method also demonstrates excellent performance in a new challenging zero-shot
setup where no paired data is used during training.
