annotate dsp/onsets/DetectionFunction.h @ 298:255e431ae3d4

* Key detector: when returning key strengths, use the peak value of the
  three underlying chromagram correlations (from 36-bin chromagram)
  corresponding to each key, instead of the mean.
  Rationale: This is the same method as used when returning the key value,
  and it's nice to have the same results in both returned value and plot.
  The peak performed better than the sum with a simple test set of triads,
  so it seems reasonable to change the plot to match the key output rather
  than the other way around.

* FFT: kiss_fftr returns only the non-conjugate bins, synthesise the rest
  rather than leaving them (perhaps dangerously) undefined.  Fixes an
  uninitialised data error in chromagram that could cause garbage results
  from key detector.

* Constant Q: remove precalculated values again, I reckon they're not
  proving such a good tradeoff.

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    QM DSP Library

    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2005-2006 Christian Landone.
    All rights reserved.
*/

#ifndef DETECTIONFUNCTION_H
#define DETECTIONFUNCTION_H

#include "maths/MathUtilities.h"
#include "maths/MathAliases.h"
#include "dsp/phasevocoder/PhaseVocoder.h"
#include "base/Window.h"

#define DF_HFC (1)
#define DF_SPECDIFF (2)
#define DF_PHASEDEV (3)
#define DF_COMPLEXSD (4)
#define DF_BROADBAND (5)

struct DFConfig{
    unsigned int stepSize; // DF step in samples
    unsigned int frameLength; // DF analysis window - usually 2*step
    int DFType; // type of detection function ( see defines )
    double dbRise; // only used for broadband df (and required for it)
    bool adaptiveWhitening; // perform adaptive whitening
    double whiteningRelaxCoeff; // if < 0, a sensible default will be used
    double whiteningFloor; // if < 0, a sensible default will be used
};

class DetectionFunction  
{
public:
    double* getSpectrumMagnitude();
    DetectionFunction( DFConfig Config );
    virtual ~DetectionFunction();
    double process( const double* TDomain );
    double process( const double* magnitudes, const double* phases );

private:
    void whiten();
    double runDF();

    double HFC( unsigned int length, double* src);
    double specDiff( unsigned int length, double* src);
    double phaseDev(unsigned int length, double *srcPhase);
    double complexSD(unsigned int length, double *srcMagnitude, double *srcPhase);
    double broadband(unsigned int length, double *srcMagnitude);
	
private:
    void initialise( DFConfig Config );
    void deInitialise();

    int m_DFType;
    unsigned int m_dataLength;
    unsigned int m_halfLength;
    unsigned int m_stepSize;
    double m_dbRise;
    bool m_whiten;
    double m_whitenRelaxCoeff;
    double m_whitenFloor;

    double* m_magHistory;
    double* m_phaseHistory;
    double* m_phaseHistoryOld;
    double* m_magPeaks;

    double* m_DFWindowedFrame; // Array for windowed analysis frame
    double* m_magnitude; // Magnitude of analysis frame ( frequency domain )
    double* m_thetaAngle;// Phase of analysis frame ( frequency domain )

    Window<double> *m_window;
    PhaseVocoder* m_phaseVoc;	// Phase Vocoder
};

#endif