Iphone read audio from built in apps

I'm trying to implement audio analysis to my app (ie for a visualizer or something). Using the Audio Queue framework, can 开发者_StackOverflowI read the output of itunes playing in the background of the device into a AudioQueueLevelMeterState variable? Once I have that variable, I can do everything I need to do, I just can't seem to figure out how to get that information. All the samples I've looked at read from either audio internal to your app, or from mic input. To keep my app as simple as possible, I'd prefer to let the user setup whatever music they want in itunes and just have it playing in the background when they load my app...

Forgive me if this question has already been answered many times, but I simply need a good lead on where to begin researching this solution. Thank You...

An iPhone app doesn't have access to audio from any other app on stock devices. You need to read the iTune's audio file data into your own app and play it yourself.