Processing iOS mic input and calculate frequency? (Swift)

Question

I'm looking for a function that can help me process the mic input on an iOS device and later help me calculate the frequency to build a music tuner. I already looked into AudioKit and would prefer to do this simple task with the core library instead of an external framework. Maybe AVFoundation and AudioToolbox offer something that I can't seem to find.

Answer 1

Accelerate has an FFT function that will give you the frequencies in a section of audio. It looks like another Stack Overflow answer already mentioned it! Probably explained better than I could.

Using the Apple FFT and Accelerate Framework