Is there a way for iTunes video player to play/pause when it is in/out of focus? I'm following a video tutorial, it's tedious to command+tab,spacebar when I want to pause/play a video. Is there a way for iTunes to start the video when the focused application is iTunes and pause the video when (going back to Unity game editor) iTunes is out of focus. 

It would be much better if I mouse hover the video iTunes plays the video, and pause the video when the mouse leaves iTunes.
That would depend on your keyboard type, which you did not disclose.

On my MacBook Air, I use the F8 to play/pause even if iTunes is in Background.