The better approach here would be to use secure links. This way, a person could not hot link the video directly. I have two mods (the Secure Streaming Mod for vShare and the Lighttpd Mod for vShare [legacy product]) that do just this. With the secure streaming mod, the actual paths to the videos cannot be linked because the link is unique to each visitor and is locked to the visitor itself. So, if that user found the link and then posted it somewhere, it would never work for anyone else. Further, the link is time limited to the requesting user so it expires after a set time anyway. With this approach, there would really never need to be a function to change all of the file names as a person could not hot link them to begin with.

To use this, you would need a VPS or your own dedicated server.