It should work basically the same as Autotalent except:

It is an LV2 plugin instead of an LADSPA plugin
It provides MIDI output of the pitch
It accepts MIDI input
It separates the pull to semitone and snap to scale functionality
It uses FFTW for the DFT routines, greatly improving performance.
Minor performance tweaks (substituting memcpy for loops, etc)
It is greatly refactored (broken into methods and structures, variables renamed)
Does not include smooth pitch jumping or LFO functionality in the first release (will add later)
The formant corrector causes artifacts not present in the original (I'm not sure how to fix, as it's the only part of the original I don't understand)

I think especially significant is the midi input and output. This would allow you to do the following:

Record an audio track in your favorite DAW while running it through the plugin, and outputting the MIDI to another track
Correct the midi however you want (keep it monophonic)
Feed the corrected MIDI track back into the plugin with the recorded audio, and listen as it corrects the pitch to match the MIDI you gave!

There are also other options, such as controlling an MIDI synth with your voice, or getting a vocoder-like effect by controlling your voice with a MIDI keyboard.

You can check out the project page for more information here or if you want a direct source download, see here.

Any feedback on the source code or plugin would be welcome.

Jeremy Salwen