Okay, so i've been having the problem where Plays.TV will not record any of League games. This is the only game I had a problem with so that is what this is addressing.
When I first installed it recorded my first game, but was a black screen, that was it. After that it didn't record at all, even after install and driver update it was still not recording.
It was brought to my attention that being in windowed or borderless mode might be the problem so I turned to full screen and it recorded consistently, but still a black screen.
I disabled my SLI, and unplugged my second monitor and it was recording! With picture this time! I then slowly started to re enable everything, first being my monitor, it was still recording. Then enabled SLI, and it was still recording, but then I tried to record while there was a window open on my second monitor and the black screen happened again. So I attempted to start the game and the recording, and then put a window on my second screen and it worked!
It seems if you have something displaying on a second screen the software bugs out and doesn't record the right screen...? I am not to sure.
Regardless, this is to help people with the same problem as I've been Googling for a few days to no avail. Make sure you are running games in full screen, and if you still have problems disable all the variables and slowly re-enable. Now I can record flawlessly as long as I don't have a window open on my separate screen.
I hope this helped someone with the same or similar problem. It's a great piece of software when you get the kinks worked out.