How do you read/write/update m4u and mp3 file meta data using cocoa/objective c?

Are there some particular library files avail开发者_运维问答able on OS/X that are relevant, I am just not sure where to start.

You'd probably want to use the QuickTime for that. There is some sample code that does this. However, it's not the nicest way to access metadata. The newer QTKit Framework somehow still requires you to fall back to the C-based APIs. There is another example from Apple embedding meta data writing into a Objective-C method. This might be the best starting point for you.