I have to do a presentation about Auto-Tune and its relation to the Fourier transform. What is a good explanation on how does Auto-Tune work?
when I read the original autotune patent few steps made me understand that everything was done in time domain (in the past, I don't know today), they didn't mention anything about overlap and add, it made me wonder if the pitch detector is so good that they didn't have to overlap and add, could they always skip or add periods in the exact position? (just out of curiosity I ended up implementing the pitch detector described in this patent, and honestly that's not all I imagined lol)
Take a look in the red marked piece of the patent paper:
Of course, the patent description also says nothing about keeping the formants, but to me it is clear that the above description is just a time domain method to apply time scale and change the pitch using resample.
youtube demo from my code here:
Although perhaps not state-of-the-art, FFT based phase vocoder algorithms have been used for time-pitch modification (with formant shift artifacts). And time-pitch modification can be used to auto-tune.