Developing for iphone/ipad/mac I have an idea for a music training app, but need to know of supporting libraries for recognizing a musical note's fundamental frequency in close to real time (100 ms delay) Accuracy should be within a few cents (hundredths of a semi tone) A search for "music" resolved the core-midi library -- fine if I want to take input from midi, but I want to be open to audio input too. And I found MusicKit, which seems to be a programmer's API for digging into Meta questions: Should I be using different search terms: Where are libraries listed? Who are the names in 3rd party libraries.