Change split view settings? Horizontal View?

can split view be made horizontal? I enjoy watching movies or tv with my friends or loved ones while face timing/messenger video chatting with them. they split view is very helpful for seeing both the movie screen and their camera screen at the same time but id like to make the split horizontal instead of vertical to fill in all the black space, since camera feed from a computer is a landscape orientation, and so are movies. If this isnt already a thing, apple needs to release this in the next update. it would be incredibly helpful.