The following information is from the V-1HD⁺ Reference Manual.
If you would like more information on this topic, please contact support via Roland Backstage.
Note that you can also use the Picture in Picture as an additional Luma or Chroma Key, the advantage to this is you can resize the window all the way up to full screen.
More information is in this article: V-1HD⁺: How to Set Up and Use Picture in Picture Overlays
