If it helps, I am using Xcode 4.3.1 and objective-c to program simple apps on an iPhone 4s running iOS 5.1.
I would like to find the documentation for a class with methods to capture the digital music signal that iTunes sends to an output device (speaker, headphones). I assume it must be accessible since it exists in the phone prior to reaching the speakers. I am not attempting a pirating move, but rather would like to route this music signal to the phone's outgoing wireless signal so that it can be heard clearly by someone on the other end of a call (ex. a method to play a favorite song, with decent sound quality, for a friend out of town). Can anyone point me in a general direction (if that direction exists) so that I can begin learning more?
Thanks, Seth
One, I'm pretty sure there's no way to get the raw audio samples from a song in the library. You can get a list of the tracks and tell the system to play one, but that all happens outside your app. Two, apps can't access the cell phone—there's no way to send audio from your app to a phone call. Three, even if the first two did work, calls are heavily compressed and tuned to voice data. Call a friend and have them play a song through the phone, see how it sounds. Not very good, I'll bet.