[Phil^]

That'd be watermarking every file on the binary level then you`re on about.
Video editing software doesnt have this in, especially not open source editing software and there is little reason for them to add it.
The only other way to watermark it in the manner you`re saying is for the computer to watermark every file that goes out of it, or for the network card/isp to watermark files as the packets pass through them.

As for the player, since they dont copy the files, only play them they cant watermark them.

Also, i would bet such a system is reverse engineered so released video files suddenly have the watermark of major companies such as those in mpaa.
It would hardly be popular if they disabled their own signatures for everyone forcing them to buy a copy of their existing movies with a new watermark. It`d be corporate suicide