annotate dsp/chromagram/ConstantQ.h @ 73:dcb555b90924

* 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 CONSTANTQ_H
#define CONSTANTQ_H

#include <vector>
#include "maths/MathAliases.h"
#include "maths/MathUtilities.h"

struct CQConfig{
    unsigned int FS;   // samplerate
    double min;        // minimum frequency
    double max;        // maximum frequency
    unsigned int BPO;  // bins per octave
    double CQThresh;   // threshold
};

class ConstantQ {
	
//public functions incl. sparsekernel so can keep out of loop in main
public:
    void process( const double* FFTRe, const double* FFTIm,
                  double* CQRe, double* CQIm );

    ConstantQ( CQConfig Config );
    ~ConstantQ();

    double* process( const double* FFTData );

    void sparsekernel();

    double hamming(int len, int n) {
	double out = 0.54 - 0.46*cos(2*PI*n/len);
	return(out);
    }
	
    int getnumwin() { return m_numWin;}
    double getQ() { return m_dQ;}
    int getK() {return m_uK ;}
    int getfftlength() { return m_FFTLength;}
    int gethop() { return m_hop;}

private:
    void initialise( CQConfig Config );
    void deInitialise();
	
    double* m_CQdata;
    unsigned int m_FS;
    double m_FMin;
    double m_FMax;
    double m_dQ;
    double m_CQThresh;
    unsigned int m_numWin;
    unsigned int m_hop;
    unsigned int m_BPO;
    unsigned int m_FFTLength;
    unsigned int m_uK;

    struct SparseKernel {
        std::vector<unsigned> is;
        std::vector<unsigned> js;
        std::vector<double> imag;
        std::vector<double> real;
    };

    SparseKernel *m_sparseKernel;
};


#endif//CONSTANTQ_H