How Can I use to watch my DirectTV cable box on my iMac 21.5 2012 version? Basically I would like to use my iMac as a TV monitor for my cable box with the HDMI cable connection point. I want to double the iMac In my kitchen as A TV screen to watch live TV from my cablebox as well as a desktop computer. i know can just buy a TV but if this is possible for cheap why do that? I've come across the elgato game capture but unsure if it's too much for my needs. Maybe there's a simple solution.