is there: App to READ CHORDS from an audio file ?

Yes. It is called Transcribe! Get it at www.seventhstring.com If you know what you are asking, you know that for an app to extract chords from audio is be very difficult. Transcribe! does a pretty good job.

dano10

yes, a very difficult technical challenge. the new version of Melodyne promises to extract individual voices from polyphonic material. i haven't tried it. for what it's worth, i do my own transcription using 'amazing slowdowner'. i just play the darn track a few times and chip away... character building.