Hello, I have a late 2013 13" rMBP and every time I try to mirror the display onto my television via Apple TV, the sound won't come out of the television, it is still coming out of the computer. I tried changing the Sound Output to Apple TV, most of the time it will not work when I try to select it, and when it finally does select, the sound still does not come out of the television. One last thing, if I am in iTunes and select Airplay, that works fine. Sound and Video come through the television. The only time I am experiencing this issue is when I mirror from my desktop. Please help!