iOS, Airplay to AppleTV without audio/sound, CoreAudio bug

Sometimes when sharing a display to the appleTV via Airplay, audio will not play over Airplay.
This is an annoying bug...

To fix in 15 sec. :
stop airplay
open the terminal and type: (you will be restarting core-audio)
sudo killall coreaudiod
start airplay, et voila, the audio is there!