BeatDetector/lib/BeatDetection.h

#ifndef ANALYZER_H
#define ANALYZER_H

//#define PLOT_ME

#ifdef PLOT_ME
    #include <KLib/misc/gnuplot/Gnuplot.h>
    #include <KLib/misc/gnuplot/GnuplotPlot.h>
    #include <KLib/misc/gnuplot/GnuplotPlotElementLines.h>
    #include <KLib/misc/gnuplot/GnuplotSplot.h>
#endif

#include "BiquadFilterGate.h"
#include "MovingAVG.h"
#include "EndlessAVG.h"

#include <iostream>


template <typename Scalar> struct BeatBand {

	BiquadFilterGate<1> filter;
	MovingAVG<Scalar> avgShort;
	MovingAVG<Scalar> avgLong;
	EndlessAVG<Scalar> avgAll;

	BeatBand() : avgShort(800), avgLong(40000) {
		avgAll.add(1);
	}

	float getMul() const {
		return avgAll.get();
	}

	float add(Scalar s) {

		const Scalar filtered = filter.filter(0, s) / getMul();
		const Scalar filtered2 = filtered*filtered;
		avgShort.add(filtered2);	// short-term average (1/40 sec)
		avgLong.add(filtered2);		// long-term average (1sec)
		avgAll.add(filtered2);		// whole average (everything)

		if (avgLong.get() < 0.0001) {return 0;}

		const float delta = std::abs(avgShort.get()) / std::abs(avgLong.get());
		//return (delta);
		return avgShort.get();

	}

};

template <typename Scalar> class BeatDetection {

    #ifdef PLOT_ME
        K::Gnuplot gp;
        K::GnuplotPlot plot;
        K::GnuplotPlotElementLines lines0;
    #endif

	BeatBand<float> band0;
	BeatBand<float> band1;
	BeatBand<float> band2;
	BeatBand<float> band3;

	MovingAVG<float> avg1;
	MovingAVG<float> avg2;



public:

	/** setup */
	BeatDetection() : avg1(600), avg2(10000) {
		setSampleRate(44100);
        #ifdef PLOT_ME
            plot.add(&lines0);
        #endif
	}

	void setSampleRate(int srate) {

		std::cout << "setting sample-rate to " << srate << std::endl;
		//band0.filter.setBandPass(70, 1, srate);			// base
		band0.filter.setLowPass(100, 1, srate);
		//band0.mul = 1;
		band1.filter.setBandPass(3500, 1.0, srate);	// claps
		//band1.mul = 3.5;
		band2.filter.setBandPass(10000, 0.4, srate);	// snare???
		//band2.mul = 5.5;

	}

	float area = 0;
	int block = 0;

	/** add single value */
	bool add(Scalar s) {

		// debug view
		static int xxx = 0; ++xxx;

		bool beat = false;
		const float val = s / 32768.0f;		// not needed
		static int x = 0; x += 1;
		float y0 = band0.add(val);
		float y1 = 0;//band1.add(val);
		float y2 = 0;//band2.add(val);
		float y = std::abs(y0)+std::abs(y1*0.5)+std::abs(y2*0.7);

		if (block > 0) {--block;}

		if (y == y) {
		//yy = yy * 0.99 + y * 0.01;
			avg1.add(y);
			avg2.add(y);
			float yy = avg1.get() - avg2.get();

			if (yy > 0.5 && !block) {
				beat = true;
				block = 9000;
			}

			// worked somewhat
//			float limit = 0.10;
//			if (yy > limit && block == 0) {
//				area += (yy-limit);
//				if (area > 1000) {
//					beat = true;
//					area = 0;
//					block = 9000;
//				}
//			} else {
//				area = 0;
//			}

            #ifdef PLOT_ME
                if (xxx % 8 == 0) {
                    lines0.add(K::GnuplotPoint2(x, yy));
                }
            #endif

		}

		// debug view?
        #ifdef PLOT_ME
		if (xxx % 5000 == 0) {show();}
        #endif

		if (beat) {
			std::cout << band0.getMul() << " " << band1.getMul() << " " << band2.getMul() << std::endl;
		}

		return beat;

	}

	/** add multiple values */
	bool add(Scalar* s, int num) {
		bool beat = false;
		for (int i = 0; i < num; ++i) {
			if (add(s[i])) {beat = true;}
		}
		return beat;
	}

    #ifdef PLOT_ME
	void show() {

		int limit = 8000;
		int d0 = lines0.size() - limit;
		if (d0 > 0) {
			lines0.remove(0, d0);
		}

		int x0 = lines0[0].x;
		int x1 = lines0[lines0.size()-1].x;
		plot.getAxisX().setRange(x0, x1);
		plot.getAxisY().setRange(-1, +5);
		//plot.getAxisY().setRange(-32768, +32768);
		gp.draw(plot);
		gp.flush();

	}
    #endif

};

#endif // ANALYZER_H