Still no fix for this in Mavericks as metioned above^
sudo killall coreaudiod command in teminal worked for me. Recently tried diabling and re-enabling my WiFi as mentioned by:
followtheeater
Re: No Audio in AirPlay mirroring from my mac (OS-ML) to Apple TV
Re: No Audio in AirPlay mirroring from my mac (OS-ML) to Apple TVDec 31, 2012 11:26 AM (in response to ronenishai)
I ran into this issue after I unplugged my apple tv while doing some furniture rearrangement. Instead of restarting my computer. I simply turned off my wifi on my mac and then turned it back on. Worked liked a charm again.
This worked perfectly and is much less of a hassle entering code into the terminal, or restarting. My hypotheses about the issue is not a problem with the ATV or OS X 10.8/10.9 but more along the lines of a Network setting problem that is causing them not to completely pair sucessfully. Will be purchasing a better router in a few months will update my findings.