TITLE:: FluidPitch
SUMMARY:: A Selection of Pitch Descriptors in Real-Time
CATEGORIES:: Libraries>FluidDecomposition
RELATED:: Guides/FluCoMa, Guides/FluidDecomposition, Classes/Pitch

DESCRIPTION::
This class implements three popular pitch descriptors, computed as frequency and the confidence in its value. It is part of the Fluid Decomposition Toolkit of the FluCoMa project.FOOTNOTE:: This was made possible thanks to the FluCoMa project ( http://www.flucoma.org/ ) funded by the European Research Council ( https://erc.europa.eu/ ) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 725899).::

	The process will return a multichannel control steam with [pitch, confidence] values, which will be repeated if no change happens within the algorithm, i.e. when the hopSize is larger than the server's kr period.

CLASSMETHODS::

METHOD:: kr
	The audio rate in, control rate out version of the object.

ARGUMENT:: in
	The audio to be processed.

ARGUMENT:: algorithm
	The algorithm to estimate the pitch. The options  are:
	TABLE::
	## 0 || Cepstrum: TODO.
	## 1 || Harmonic Product Spectrum: TODO.
	## 2 || YinFFT: TODO.
	::


ARGUMENT:: winSize
	The window size. As sinusoidal estimation relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. http://www.subsurfwiki.org/wiki/Gabor_uncertainty

ARGUMENT:: hopSize
	The window hope size. As sinusoidal estimation relies on spectral frames, we need to move the window forward. It can be any size but low overlap will create audible artefacts. The -1 default value will default to half of winSize (overlap of 2).

ARGUMENT:: fftSize
	The inner FFT/IFFT size. It should be at least 4 samples long, at least the size of the window, and a power of 2. Making it larger allows an oversampling of the spectral precision. The -1 default value will default to windowSize.

ARGUMENT:: maxFFTSize
	How large can the FFT be, by allocating memory at instantiation time. This cannot be modulated.

RETURNS::
	A 2-channel KR signal with the [pitch, confidence] descriptors. The latency is winSize.


EXAMPLES::


code::
//create a monitoring bus for the descriptors
b = Bus.new(\control,0,4);

//create a monitoring window for the values
(
w = Window("Frequency Monitor", Rect(10, 10, 220, 115)).front;

c = Array.fill(4, {arg i; StaticText(w, Rect(10, i * 25 + 10, 135, 20)).background_(Color.grey(0.7)).align_(\right)});
c[0].string = ("FluidPitch: ");
c[1].string = ("confidence: ");
c[2].string = ("SC Pitch: ");
c[3].string = ("Confidence: ");

a = Array.fill(4, {arg i;
	StaticText(w, Rect(150, i * 25 + 10, 60, 20)).background_(Color.grey(0.7)).align_(\center);
});
)

//routine to update the parameters
(
r = Routine {
	{

		b.get({ arg val;
			{
				if(w.isClosed.not) {
					val.do({arg item,index;
						a[index].string = item.round(0.01)})
				}
			}.defer
		});

		0.1.wait;
	}.loop

}.play
)

//test signals, all in one synth
(
x = {
	arg freq=220, type = 0, noise = 0;
			var source = PinkNoise.ar(noise) + Select.ar(type,[SinOsc.ar(freq,mul:0.1), VarSaw.ar(freq,mul:0.1), Saw.ar(freq,0.1), Pulse.ar(freq,mul:0.1), Mix.new(Array.fill(8, {arg i; SinOsc.ar(LFNoise1.kr(0.1.rand,10,220*(i+1)),mul:(i+1).reciprocal * 0.1)}))]);
	Out.kr(b, FluidPitch.kr(source) ++ Pitch.kr(source));
	source.dup;
}.play;
)

// the built-in is slightly worse on pure sinewaves
x.set(\freq, 220)
x.set(\freq, 440)

// adding harmonics, by changing to triangle (1), saw (2) or square (3) shows that spectral algo are more resilient when signal are richer
x.set(\type, 1)
x.set(\type, 2)
x.set(\type, 3)

// adding noise shows the comparative sturdiness of the spectral pitch tracker
x.set(\noise, 0.05)
::

STRONG::a more musical example::
CODE::
// play a noisy synth file
b = Buffer.read(s,File.realpath(FluidPitch.class.filenameSymbol).dirname.withTrailingSlash ++ "../AudioFiles/Tremblay-ASWINE-ScratchySynth-M.wav");
b.play(true);

//insert a selective reverb - sending only the material with very high pitch confidence
(
f = {var source, rev;
	source = In.ar(0,2);
	rev = FreeVerb.ar(DelayN.ar(source,delaytime:1024/s.sampleRate) * Lag.kr((FluidPitch.kr(source.sum)[1] > 0.98),0.01), 1);
	ReplaceOut.ar(0, rev+ source);
}.play(addAction:\addToTail);
)

// free the effect
f.free

// insert a stereo delay instead (as well) using the same
(
f = {
	var source, todelay, delay1, delay2, delay3, feedback, mod1, mod2, mod3, mod4;
	//read the source
	source = In.ar(0,2);

	// generate modulators that are coprime in frequency
	mod1 = SinOsc.ar(1, 0, 0.001);
	mod2 = SinOsc.ar(((617 * 181) / (461 * 991)), 0, 0.001);
	mod3 = SinOsc.ar(((607 * 193) / (491 * 701)), 0, 0.001);
	mod4 = SinOsc.ar(((613 * 191) / (463 * 601)), 0, 0.001);

	// gate the signal to send to the delays
	todelay = DelayN.ar(source,delaytime:1024/s.sampleRate) * Lag.kr((FluidPitch.kr(source.sum)[1] > 0.98),0.01);

	// delay network
	feedback = LocalIn.ar(3);// take the feedback in for the delays
	delay1 = DelayC.ar(BPF.ar(todelay+feedback[1]+(feedback[2] * 0.3), 987, 6.7,0.35),0.123,0.122+(mod1*mod2));
	delay2 = DelayC.ar(BPF.ar(todelay+feedback[0]+(feedback[2] * 0.3), 1987, 6.7,0.35),0.345,0.344+(mod3*mod4));
	delay3 = DelayC.ar(BPF.ar(todelay+feedback[1], 1456, 6.7,0.35),0.567,0.566+(mod1*mod3),0.6);
	LocalOut.ar([delay1,delay2, delay3]); // write the feedback for the delays

			ReplaceOut.ar(0, source + [delay1+delay3,delay2+delay3]);
}.play(addAction:\addToTail);
)

::