annotate dsp/chromagram/ChromaProcess.cpp @ 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.
*/


#include "ChromaProcess.h"
#include "maths/Histogram.h"
#include <math.h>
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

ChromaProcess::ChromaProcess()
{

}

ChromaProcess::~ChromaProcess()
{

}

int ChromaProcess::findChromaBias( vector<double> chromaVector, unsigned int BPO, unsigned int frames )
{
    vector<double> newChroma;
    vector<int> peakIndex;
    vector<int> modPeakIndex;

    unsigned int chromaLength = chromaVector.size(); 

    unsigned int newLength = chromaLength + (2*BPO);

    newChroma.resize( newLength );
    newChroma.clear();

    modPeakIndex.resize( newLength );
    modPeakIndex.clear();

    //adds last row at the top and first row at the bottom to create 
    //circularity - effectively adds 2 to the bpo-length of the vectors:

    for( unsigned int i = 0; i < BPO; i++ )
    {
	newChroma.push_back( chromaVector[ chromaLength - BPO + i ] );
    }

    for( unsigned i = 0; i < chromaLength; i++ )
    {
	newChroma.push_back( chromaVector[ i ] );
    }

    for( unsigned i = 0; i < BPO; i++ )
    {
	newChroma.push_back( chromaVector[ i ] );
    }

    // pick peaks in the chroma
    peakIndex = getPeaks( newChroma, BPO );

    // modularises to res = bpo/12 bins:
    // corrects the mod value for bin 3
    modPeakIndex = mod( peakIndex, 3 );

    // finds the highest concentration of peaks on the bpo/12 bin resolution
    THistogram<int> m_hist(3);

    double ave, adev, sdev, var, skew, ccurt;

    m_hist.compute(modPeakIndex);

    m_hist.getMoments( modPeakIndex, ave, adev, sdev, var, skew, ccurt );

    vector <double> histogram = m_hist.geTHistogramD();
    //////////////////////////////////////////////////////////////////////////////

    ///////////////////////////////////////////////////////////////////////////
	// Find actual bias from histogram
	int minIdx, maxIdx;
	double min, max;

	findHistMaxMin( histogram, &max, &maxIdx, &min, &minIdx );

/*
  FILE* foutchroma = fopen("../testdata/newchroma.bin","wb");
  FILE* foutpeaks = fopen("../testdata/peaks.bin","wb");


  fwrite( &chromaVector[0], sizeof(double), chromaVector.size(), foutchroma );
  fwrite( &histogram[0], sizeof(double), histogram.size(), foutpeaks );

  fclose( foutchroma );
  fclose( foutpeaks );
*/
	return maxIdx - 1;
}


vector <int> ChromaProcess::getPeaks(vector <double> chroma, unsigned int BPO)
{
    vector <int> peaks;
	
    double pre = 0;
    double post = 0;
    double current = 0;

    unsigned int BPOCounter = 0;
    unsigned int mult = 0;
    unsigned int idx = 0;

    for( unsigned int i = 0; i < chroma.size() - 0; i++ )
    {
	BPOCounter++;

	pre = chroma[ i ];
	current = chroma[ i + 1 ];
	post = chroma[ i + 2 ];
		
	if( (current > 0) && (current > pre) && (current > post) )
	{
	    peaks.push_back( BPOCounter + 1);
	}

		
	if( BPOCounter == (BPO - 2 ) )
	{
	    BPOCounter = 0;
	    i+=2;
	}
		
    }

    /*
      for( unsigned int i = 1; i < chroma.size() - 1; i++ )
      {
      BPOCounter++ ;

      pre = chroma[ i - 1 ];
      current = chroma[ i ];
      post = chroma[ i + 1 ];
		
      if( (current > 0) && (current > pre) && (current > post) )
      {
      peaks.push_back( BPOCounter + 1 );
      }

      if( BPOCounter == (PO - 1) )
      {
      BPOCounter = 1;
      i+=2;
      }
      }
    */
    return peaks;
}

vector <int> ChromaProcess::mod(vector <int> input, int res)
{
    vector <int> result;

    for( unsigned int i = 0; i < input.size(); i++ )
    {
	int val = input[ i ];
	int res = val - res * floor( (double)val / (double)res );

	if( val != 0 )
	{
	    if( res == 0 )
		res = 3;

	    result.push_back( res );
	}
	else
	{
	    result.push_back( val );
	}
    }
    return result;
}

void ChromaProcess::findHistMaxMin( vector<double> hist, double* max, int* maxIdx, double* min, int* minIdx )
{
    double temp = 0.0;
    unsigned int vecLength = hist.size();

    *minIdx = 0;
    *maxIdx = 0;

    *min = hist[0];
    *max = *min;

    for( unsigned int u = 0; u < vecLength; u++ )
    {
	temp = hist[ u ];

	if( temp < *min )
	{
	    *min =  temp ;
	    *minIdx = u;
	}
	if( temp > *max )
	{
	    *max =  temp ;
	    *maxIdx = u;
	}

    }
}