If you're going to leave it open (as suggested above), download app Caffeine - it will keep it awake as long as you don't close the lid.I guess you don't have a bluetooth mouse or keyboard? Or a USB memory stick or anything? Once you hook up the TV, close the lid and then hit a button the mouse/keyboard, or plug in a memory stick or something. But you still need to be able to hit "play" so you'll need a mouse or iPhone virtual mouse "remote pad" or something.
Otherwise, just leave it open and turn down the brightness all the way.
Have you tried in System Preferences > Energy Saver> Computer Sleep>Never and/or Display Sleep>Never.I do have a mouse and I already have caffeine. I never thought about the mouse before so I will give that a try. And as for looking in system preferences I have done that and have found nothing.
Caffeine will temporarily override Energy Saver settings and keep your Mac awake with the lid open.I am looking for an app that will keep my MBP awake when I close the lid. I hook up the MBP to the TV alot and watch movies. I hate having the lid open. Can someone help please?