I have been working hard on AirPlay to try to understand what it takes to get BitPerfect to work smoothly with it under the combination of Yosemite and iTunes 12.0.1.  Unfortunately I don’t have a definitive answer for you, but I am at least starting to get a handle on its behaviour.  I thought you might be interested to read some of this.

The problem is, it either works or it doesn’t, and I can’t figure out why.  There are two main modes of “doesn’t work”.  One is where BitPerfect’s menu bar icon stays black.  This one happens rarely and generally only at the first attempt.  It means that BitPerfect cannot access the AirPlay Device.  The other is where the icon starts green, goes briefly black, and then stays green but with no music audible.  This means that BitPerfect is streaming music to the AirPlay Device, which as far as BitPerfect is concerned is responding in the way it normally would.  I have been wrestling with every combination of the various settings and sequences that might impact AirPlay behaviour but despite some successes, nothing has proven to be the magic bullet.

My first potential “Aha!” moment was when I got to the point where iTunes would throw up a message to the effect that “I can’t find the Airport Express” and offers me two options, “Cancel” or “Continue using the Computer Speaker”.  The secret seems to be to select “Continue using the Computer Speaker”.  “Cancel” is the wrong choice.  I spent some time trying to determine what would cause this message to appear, but after a while I just stopped seeing it, and I haven’t actually seen it now since early yesterday.  So that remains a puzzle.

The next interesting observation is a significant deviation from the setup that we have been recommending since Mountain Lion and Mavericks.  iTunes has its own little AirPlay icon (next to its volume control) where you can select between the various AirPlay devices and “Computer”.  It used to be that it was necessary to select the desired AirPlay device, but now I am finding that AirPlay never works unless “Computer” is selected, and not the other way around.

Yesterday, using my Mac Mini, it appeared that the required solution was to select AirPlay as the default system output device using Audio Midi Setup, then launch BitPerfect, and have BitPerfect launch iTunes (whether automatically or manually), then select “Computer” as the output device from the iTunes AirPlay control.  But when I came to confirm my findings this morning, I found that it didn’t seem to matter whether or not I set the default system output device to AirPlay or to something else.  All that matters is that I set the iTunes AirPlay control to “Computer”.  You must select the desired AirPlay device (if you have more than one) in Audio Midi Setup.  I even experimented with connecting the Mac Mini to the network by Ethernet (its normal configuration) or by WiFi.  It didn’t make any difference.

While all this was happening, on my RMBP (which had Yosemite and iTunes 12.0.1 installed) it seemed that AirPlay would always work first time.  I have a second, older MBP and so I installed Yosemite and iTunes 12.0.1 on that machine also.  This morning I have added that to the mix.  It seems that both MBPs have no problems at all getting BitPerfect and AirPlay to work together, provided I set the iTunes AirPlay control to “Computer”.  For the most part the Mac Mini also works too.  However, it took three or four attempts, restarting BitPerfect and iTunes each time in between, before it started working consistently.  With each of these Macs, once AirPlay starts working, it seems to stay working until you stop playback for a while, or quit iTunes/BitPerfect.

So there you have a summary of a couple of days of intensive AirPlay experimentation.  Set the iTunes AirPlay control to “Computer” and it will either work or it won’t.  If it doesn’t, then quit BitPerfect and iTunes and start again.  Rinse and repeat as necessary.  You may be lucky in that you have a Mac which is pre-disposed to want to work well with AirPlay (like my two MBPs) or you may be unlucky that your Mac does not prefer to play ball (like my Mac Mini).  It’s all I have at the moment, I’m afraid.  I have no idea whether or not you will see the same behaviour.  I will continue my experiments, albeit at a less intense level, as I am (a) running short of good ideas, and (b) have other things piling up on my plate.

… As a brief follow-up, here are some thoughts and observations regarding my AppleTV.