Copyright applies to any work the instant it is created. "Filing copyright" just means documenting where and when so that you can later help prove you have copyright. So yes, if you scribble a monkey on a napkin, you have copyright over that napkin monkey. Everything else is just proving it.
With this, if Samwell didn't own the rights to the video, then he's not authorized to give permission. Otherwise, it's like you buying my car from me, and then me telling my neighbor, "Sure! You can borrow "my" car!"