When playing movies via Airplay to AppleTV I used to be able to switch outputs via Sound preference pane (either AppleTV or Digital optical). This is not longer possible, when playing via AppleTV the sound preference pane indicates digital optical output (which is my system preference) but no sound is output to that port. Switching it to AppleTV and back to Digital forces the video output back to the main computer screen, that is airplay is terminated . How to recover the previous flexibility, i.e. how to get video via Airplay on Apple TV and sound on Digital optical at the same time. (get better audio from my stereo when playing from the digital optical mac output than via AppleTV to the tv and from the TV to the receiver via digital coax)
iMac, OS X El Capitan (10.11.1), 27" mid 2011
