Sent from my SAMSUNG-SM-N900A using XDA Premium 4 mobile app
I have one that works perfect. Works when youtube is minimized too.
Only problem is that its an older version of the youtube app.
I think this is the thread... http://forum.xda-developers.com/show....php?t=1529715
After you have it installed, hit the Menu button > Advanced Settings (scroll all the way down) > Check the Screen Off Playback button
Thats pretty much it....