It would be helpful to have a larger version of this video to help analyze it. Something definitely crosses the room, and it doesn't look like a mere shadow cast by something off camera. Some hoaxers have been able to create an effect such as this by videotaping an empty room, then taping the same shot with a live person crossing, and then combining the two videos. The opacity of the version with the person in it can be lessened to give it a transparent, ghostly appearance. It's possible that's what we're seeing here, but I don't know for sure. If it's not a hoax, it might be a ghost. What's your opinion?