Install Link Shell Extension. http://schinagl.priv.at/nt/hardlinkshellext/hardlinkshellext.html
Move the video directory to another hard drive.
Right-click on the directory and select "Pick Link Source"
Go back to the parent directory of the original video directory location.
Right-click on white space in the directory and select Drop As > Junction (or Symbolic Link)
Folder structure should still be the same on the Windows drive but everything is being written to the second HD.
This works for moving games on and off SSDs without reinstalling too. Although for Steam games, it's more convenient to use Steam Mover to manage it.