I think the description of the video says it best:

"Stanford artificial intelligence researchers have developed software that makes it easy to reach inside an existing video and place a photo on the wall so realistically that it looks like it was there from the beginning. The photo is not pasted on top of the existing video, but embedded in it It works for videos as well - you can play a video on a wall inside your video. The technology can cheaply do some of the tricks normally performed by expensive commercial editing systems."

Thank you Stanford.