Free Music Instrument Tunerhttp://gillesdegottex.github.io/fmit
FMIT is a graphical utility for tuning your musical instruments, with error
and volume history and advanced features like microtonal tuning, statistics,
and various views like waveform shape, harmonics ratios and real-time Discrete
Fourier Transform (DFT).
* Estimate the fundamental frequency (f0) of an audio signal, in real-time.
(the f0, not the perceived pitch)
* Keep any view optional so that the interface can be as simple as possible.
(make it easy to see on a distant screen)
* Support as many sound systems as possible.