Can you mute via the Apple TV remote?
it’s always baffled me that you can control the volume on your 4th gen Apple remote but you can’t mute it, which is one of the things you most often do, besides change the volume. At least I didn’t know any way to do it and online research didn’t help.
iMac, OS X Yosemite (10.10.1), 16 Gb RAM, Fusion Drive