annotate dsp/tempotracking/TempoTrack.cpp @ 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 and Matthew Davies.
    All rights reserved.
*/

#include "TempoTrack.h"

#include "maths/MathAliases.h"
#include "maths/MathUtilities.h"

#include <iostream>

#include <cassert>

//#define DEBUG_TEMPO_TRACK 1


#define RAY43VAL

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

TempoTrack::TempoTrack( TTParams Params )
{
    m_tempoScratch = NULL;
    m_rawDFFrame = NULL;
    m_smoothDFFrame = NULL;
    m_frameACF = NULL;
	m_smoothRCF = NULL;

    m_dataLength = 0;
    m_winLength = 0;
    m_lagLength = 0;

    m_rayparam = 0;
    m_sigma = 0;
    m_DFWVNnorm = 0;

    initialise( Params );
}

TempoTrack::~TempoTrack()
{
    deInitialise();
}

void TempoTrack::initialise( TTParams Params )
{	
    m_winLength = Params.winLength;
    m_lagLength = Params.lagLength;

    m_rayparam	 = 43.0;
    m_sigma = sqrt(3.9017);
    m_DFWVNnorm = exp( ( log( 2.0 ) / m_rayparam ) * ( m_winLength + 2 ) );

    m_rawDFFrame = new double[ m_winLength ];
    m_smoothDFFrame = new double[ m_winLength ];
    m_frameACF = new double[ m_winLength ];
    m_tempoScratch = new double[ m_lagLength ];
	m_smoothRCF = new double[ m_lagLength ];


    unsigned int winPre = Params.WinT.pre;
    unsigned int winPost = Params.WinT.post;

    m_DFFramer.configure( m_winLength, m_lagLength );
	
    m_DFPParams.length = m_winLength;
    m_DFPParams.AlphaNormParam = Params.alpha;
    m_DFPParams.LPOrd = Params.LPOrd;
    m_DFPParams.LPACoeffs = Params.LPACoeffs;
    m_DFPParams.LPBCoeffs = Params.LPBCoeffs;
    m_DFPParams.winPre = Params.WinT.pre;
    m_DFPParams.winPost = Params.WinT.post;
    m_DFPParams.isMedianPositive = true;
	
    m_DFConditioning = new DFProcess( m_DFPParams );


	// these are parameters for smoothing m_tempoScratch
    m_RCFPParams.length = m_lagLength;
    m_RCFPParams.AlphaNormParam = Params.alpha;
    m_RCFPParams.LPOrd = Params.LPOrd;
    m_RCFPParams.LPACoeffs = Params.LPACoeffs;
    m_RCFPParams.LPBCoeffs = Params.LPBCoeffs;
    m_RCFPParams.winPre = Params.WinT.pre;
    m_RCFPParams.winPost = Params.WinT.post;
    m_RCFPParams.isMedianPositive = true;

    m_RCFConditioning = new DFProcess( m_RCFPParams );

}

void TempoTrack::deInitialise()
{	
    delete [] m_rawDFFrame;
	
    delete [] m_smoothDFFrame;

	delete [] m_smoothRCF;	
	
    delete [] m_frameACF;

    delete [] m_tempoScratch;

    delete m_DFConditioning;
	
	delete m_RCFConditioning;

}

void TempoTrack::createCombFilter(double* Filter, unsigned int winLength, unsigned int TSig, double beatLag)
{
    unsigned int i;

    if( beatLag == 0 )
    {
	for( i = 0; i < winLength; i++ )
	{    
	    Filter[ i ] = ( ( i + 1 ) / pow( m_rayparam, 2.0) ) * exp( ( -pow(( i + 1 ),2.0 ) / ( 2.0 * pow( m_rayparam, 2.0))));
	}
    }
    else
    {	
	m_sigma = beatLag/4;
	for( i = 0; i < winLength; i++ )
	{
	    double dlag = (double)(i+1) - beatLag;
	    Filter[ i ] =  exp(-0.5 * pow(( dlag / m_sigma), 2.0) ) / (sqrt( 2 * PI) * m_sigma);
	}
    }
}

double TempoTrack::tempoMM(double* ACF, double* weight, int tsig)
{

    double period = 0;
    double maxValRCF = 0.0;
    unsigned int maxIndexRCF = 0;

    double* pdPeaks;

    unsigned int maxIndexTemp;
    double	maxValTemp;
    unsigned int count; 
	
    unsigned int numelem,i,j;
    int a, b;

    for( i = 0; i < m_lagLength; i++ )
	m_tempoScratch[ i ] = 0.0;

    if( tsig == 0 ) 
    {
	//if time sig is unknown, use metrically unbiased version of Filterbank
	numelem = 4;
    }
    else
    {
	numelem = tsig;
    }

#ifdef DEBUG_TEMPO_TRACK
    std::cerr << "tempoMM: m_winLength = " << m_winLength << ", m_lagLength = " << m_lagLength << ", numelem = " << numelem << std::endl;
#endif

    for(i=1;i<m_lagLength-1;i++)
    {
	//first and last output values are left intentionally as zero
	for (a=1;a<=numelem;a++)
	{
	    for(b=(1-a);b<a;b++)
	    {
		if( tsig == 0 )
		{					
		    m_tempoScratch[i] += ACF[a*(i+1)+b-1] * (1.0 / (2.0 * (double)a-1)) * weight[i];
		}
		else
		{
		    m_tempoScratch[i] += ACF[a*(i+1)+b-1] * 1 * weight[i];
		}
	    }
	}
    }


	//////////////////////////////////////////////////
	// MODIFIED BEAT PERIOD EXTRACTION //////////////
	/////////////////////////////////////////////////

	// find smoothed version of RCF ( as applied to Detection Function)
	m_RCFConditioning->process( m_tempoScratch, m_smoothRCF);

	if (tsig != 0) // i.e. in context dependent state
	{	
//     NOW FIND MAX INDEX OF ACFOUT
            for( i = 0; i < m_lagLength; i++)
            {
                if( m_tempoScratch[ i ] > maxValRCF)
                {
                    maxValRCF = m_tempoScratch[ i ];
                    maxIndexRCF = i;
                }
            }
	}
	else // using rayleigh weighting
	{
		vector <vector<double> > rcfMat;
	
		double sumRcf = 0.;
	
		double maxVal = 0.;
		// now find the two values which minimise rcfMat
		double minVal = 0.;
		int p_i = 1; // periodicity for row i;
		int p_j = 1; //periodicity for column j;
	
	
		for ( i=0; i<m_lagLength; i++)
		{
			m_tempoScratch[i] =m_smoothRCF[i];
		}	

		// normalise m_tempoScratch so that it sums to zero.
		for ( i=0; i<m_lagLength; i++)
		{
			sumRcf += m_tempoScratch[i];
		}	
	
		for( i=0; i<m_lagLength; i++)
		{
			m_tempoScratch[i] /= sumRcf;
		}	
	
		// create a matrix to store m_tempoScratchValues modified by log2 ratio
		for ( i=0; i<m_lagLength; i++)
		{
			rcfMat.push_back  ( vector<double>() ); // adds a new row...
		}
	
		for (i=0; i<m_lagLength; i++)
		{
			for (j=0; j<m_lagLength; j++)
			{
				rcfMat[i].push_back (0.);
			}
		}
	
		// the 'i' and 'j' indices deliberately start from '1' and not '0'
		for ( i=1; i<m_lagLength; i++)
		{
			for (j=1; j<m_lagLength; j++)
			{
				double log2PeriodRatio = log( static_cast<double>(i)/static_cast<double>(j) ) / log(2.0);
				rcfMat[i][j] = ( abs(1.0-abs(log2PeriodRatio)) );
				rcfMat[i][j] += ( 0.01*( 1./(m_tempoScratch[i]+m_tempoScratch[j]) ) );
			}
		}
		
		// set diagonal equal to maximum value in rcfMat 
		// we don't want to pick one strong middle peak - we need a combination of two peaks.
	
		for ( i=1; i<m_lagLength; i++)
		{
			for (j=1; j<m_lagLength; j++)
			{
				if (rcfMat[i][j] > maxVal)
				{	
					maxVal = rcfMat[i][j];
				}
			}
		}
	
		for ( i=1; i<m_lagLength; i++)
		{
			rcfMat[i][i] = maxVal;
		}
	
		// now find the row and column number which minimise rcfMat
		minVal = maxVal;
		
		for ( i=1; i<m_lagLength; i++)
		{
			for ( j=1; j<m_lagLength; j++)
			{
				if (rcfMat[i][j] < minVal)
				{	
					minVal = rcfMat[i][j];
					p_i = i;
					p_j = j;
				}
			}
		}
	
	
		// initially choose p_j (arbitrary) - saves on an else statement
		int beatPeriod = p_j;
		if (m_tempoScratch[p_i] > m_tempoScratch[p_j])
		{
			beatPeriod = p_i;
		}
		
		// now write the output
		maxIndexRCF = static_cast<int>(beatPeriod);
	}


    double locked = 5168.f / maxIndexRCF;
    if (locked >= 30 && locked <= 180) {
        m_lockedTempo = locked;
    }

#ifdef DEBUG_TEMPO_TRACK
    std::cerr << "tempoMM: locked tempo = " << m_lockedTempo << std::endl;
#endif

    if( tsig == 0 )
	tsig = 4;


#ifdef DEBUG_TEMPO_TRACK
std::cerr << "tempoMM: maxIndexRCF = " << maxIndexRCF << std::endl;
#endif
	
    if( tsig == 4 )
    {
#ifdef DEBUG_TEMPO_TRACK
        std::cerr << "tsig == 4" << std::endl;
#endif

	pdPeaks = new double[ 4 ];
	for( i = 0; i < 4; i++ ){ pdPeaks[ i ] = 0.0;}

	pdPeaks[ 0 ] = ( double )maxIndexRCF + 1;

	maxIndexTemp = 0;
	maxValTemp = 0.0;
	count = 0;

	for( i = (2 * maxIndexRCF + 1) - 1; i < (2 * maxIndexRCF + 1) + 2; i++ )
	{
	    if( ACF[ i ] > maxValTemp )
	    {
		maxValTemp = ACF[ i ];
		maxIndexTemp = count;
	    }
	    count++;
	}
	pdPeaks[ 1 ] = (double)( maxIndexTemp + 1 + ( (2 * maxIndexRCF + 1 ) - 2 ) + 1 )/2;

	maxIndexTemp = 0;
	maxValTemp = 0.0;
	count = 0;

	for( i = (3 * maxIndexRCF + 2 ) - 2; i < (3 * maxIndexRCF + 2 ) + 3; i++ )
	{
	    if( ACF[ i ] > maxValTemp )
	    {
		maxValTemp = ACF[ i ];
		maxIndexTemp = count;
	    }
	    count++;
	}
	pdPeaks[ 2 ] = (double)( maxIndexTemp + 1 + ( (3 * maxIndexRCF + 2) - 4 ) + 1 )/3;

	maxIndexTemp = 0;
	maxValTemp = 0.0;
	count = 0;

	for( i = ( 4 * maxIndexRCF + 3) - 3; i < ( 4 * maxIndexRCF + 3) + 4; i++ )
	{
	    if( ACF[ i ] > maxValTemp )
	    {
		maxValTemp = ACF[ i ];
		maxIndexTemp = count;
	    }
	    count++;
	}
	pdPeaks[ 3 ] = (double)( maxIndexTemp + 1 + ( (4 * maxIndexRCF + 3) - 9 ) + 1 )/4 ;


	period = MathUtilities::mean( pdPeaks, 4 );
    }
    else
    { 
#ifdef DEBUG_TEMPO_TRACK
       std::cerr << "tsig != 4" << std::endl;
#endif

	pdPeaks = new double[ 3 ];
	for( i = 0; i < 3; i++ ){ pdPeaks[ i ] = 0.0;}

	pdPeaks[ 0 ] = ( double )maxIndexRCF + 1;

	maxIndexTemp = 0;
	maxValTemp = 0.0;
	count = 0;

	for( i = (2 * maxIndexRCF + 1) - 1; i < (2 * maxIndexRCF + 1) + 2; i++ )
	{
	    if( ACF[ i ] > maxValTemp )
	    {
		maxValTemp = ACF[ i ];
		maxIndexTemp = count;
	    }
	    count++;
	}
	pdPeaks[ 1 ] = (double)( maxIndexTemp + 1 + ( (2 * maxIndexRCF + 1 ) - 2 ) + 1 )/2;

	maxIndexTemp = 0;
	maxValTemp = 0.0;
	count = 0;

	for( i = (3 * maxIndexRCF + 2 ) - 2; i < (3 * maxIndexRCF + 2 ) + 3; i++ )
	{
	    if( ACF[ i ] > maxValTemp )
	    {
		maxValTemp = ACF[ i ];
		maxIndexTemp = count;
	    }
	    count++;
	}
	pdPeaks[ 2 ] = (double)( maxIndexTemp + 1 + ( (3 * maxIndexRCF + 2) - 4 ) + 1 )/3;


	period = MathUtilities::mean( pdPeaks, 3 );
    }

    delete [] pdPeaks;

    return period;
}

void TempoTrack::stepDetect( double* periodP, double* periodG, int currentIdx, int* flag )
{
    double stepthresh = 1 * 3.9017;

    if( *flag )
    {
	if(abs(periodG[ currentIdx ] - periodP[ currentIdx ]) > stepthresh)
	{
	    // do nuffin'
	}
    }
    else
    {
	if(fabs(periodG[ currentIdx ]-periodP[ currentIdx ]) > stepthresh)
	{
	    *flag = 3;
	}
    }
}

void TempoTrack::constDetect( double* periodP, int currentIdx, int* flag )
{
    double constthresh = 2 * 3.9017;

    if( fabs( 2 * periodP[ currentIdx ] - periodP[ currentIdx - 1] - periodP[ currentIdx - 2] ) < constthresh)
    {
	*flag = 1;
    }
    else
    {
	*flag = 0;
    }
}

int TempoTrack::findMeter(double *ACF, unsigned int len, double period)
{
    int i;
    int p = (int)MathUtilities::round( period );
    int tsig;

    double Energy_3 = 0.0;
    double Energy_4 = 0.0;

    double temp3A = 0.0;
    double temp3B = 0.0;
    double temp4A = 0.0;
    double temp4B = 0.0;

    double* dbf = new double[ len ]; int t = 0;
    for( unsigned int u = 0; u < len; u++ ){ dbf[ u ] = 0.0; }

    if( (double)len < 6 * p + 2 )
    {
	for( i = ( 3 * p - 2 ); i < ( 3 * p + 2 ) + 1; i++ )
	{
	    temp3A += ACF[ i ];
	    dbf[ t++ ] = ACF[ i ];
	}
	
	for( i = ( 4 * p - 2 ); i < ( 4 * p + 2 ) + 1; i++ )
	{
	    temp4A += ACF[ i ];
	}

	Energy_3 = temp3A;
	Energy_4 = temp4A;
    }
    else
    {
	for( i = ( 3 * p - 2 ); i < ( 3 * p + 2 ) + 1; i++ )
	{
	    temp3A += ACF[ i ];
	}
	
	for( i = ( 4 * p - 2 ); i < ( 4 * p + 2 ) + 1; i++ )
	{
	    temp4A += ACF[ i ];
	}

	for( i = ( 6 * p - 2 ); i < ( 6 * p + 2 ) + 1; i++ )
	{
	    temp3B += ACF[ i ];
	}
	
	for( i = ( 2 * p - 2 ); i < ( 2 * p + 2 ) + 1; i++ )
	{
	    temp4B += ACF[ i ];
	}

	Energy_3 = temp3A + temp3B;
	Energy_4 = temp4A + temp4B;
    }

    if (Energy_3 > Energy_4)
    {
	tsig = 3;
    }
    else
    {
	tsig = 4;
    }


    return tsig;
}

void TempoTrack::createPhaseExtractor(double *Filter, unsigned int winLength, double period, unsigned int fsp, unsigned int lastBeat)
{	
    int p = (int)MathUtilities::round( period );
    int predictedOffset = 0;

#ifdef DEBUG_TEMPO_TRACK
    std::cerr << "TempoTrack::createPhaseExtractor: period = " << period << ", p = " << p << std::endl;
#endif

    if (p > 10000) {
        std::cerr << "TempoTrack::createPhaseExtractor: WARNING! Highly implausible period value " << p << "!" << std::endl;
        period = 5168 / 120;
    }

    double* phaseScratch = new double[ p*2 + 2 ];
    for (int i = 0; i < p*2 + 2; ++i) phaseScratch[i] = 0.0;

	
    if( lastBeat != 0 )
    {
	lastBeat = (int)MathUtilities::round((double)lastBeat );///(double)winLength);

        predictedOffset = lastBeat + p - fsp;

        if (predictedOffset < 0) 
        {
            lastBeat = 0;
        }
    }

    if( lastBeat != 0 )
    {
	int mu = p;
	double sigma = (double)p/8;
	double PhaseMin = 0.0;
	double PhaseMax = 0.0;
	unsigned int scratchLength = p*2;
	double temp = 0.0;

	for(  int i = 0; i < scratchLength; i++ )
	{
	    phaseScratch[ i ] = exp( -0.5 * pow( ( i - mu ) / sigma, 2 ) ) / ( sqrt( 2*PI ) *sigma );
	}

	MathUtilities::getFrameMinMax( phaseScratch, scratchLength, &PhaseMin, &PhaseMax );
			
	for(int i = 0; i < scratchLength; i ++)
	{
	    temp = phaseScratch[ i ];
	    phaseScratch[ i ] = (temp - PhaseMin)/PhaseMax;
	}

#ifdef DEBUG_TEMPO_TRACK
        std::cerr << "predictedOffset = " << predictedOffset << std::endl;
#endif

	unsigned int index = 0;
	for (int i = p - ( predictedOffset - 1); i < p + ( p - predictedOffset) + 1; i++)
	{
#ifdef DEBUG_TEMPO_TRACK
            std::cerr << "assigning to filter index " << index << " (size = " << p*2 << ")" << " value " << phaseScratch[i] << " from scratch index " << i << std::endl;
#endif
	    Filter[ index++ ] = phaseScratch[ i ];
	}
    }
    else
    {
	for( int i = 0; i < p; i ++)
	{
	    Filter[ i ] = 1;
	}
    }
	
    delete [] phaseScratch;
}

int TempoTrack::phaseMM(double *DF, double *weighting, unsigned int winLength, double period)
{
    int alignment = 0;
    int p = (int)MathUtilities::round( period );

    double temp = 0.0;

    double* y = new double[ winLength ];
    double* align = new double[ p ];

    for( int i = 0; i < winLength; i++ )
    {	
	y[ i ] = (double)( -i + winLength  )/(double)winLength;
	y[ i ] = pow(y [i ],2.0); // raise to power 2.
    }

    for( int o = 0; o < p; o++ )
    { 
	temp = 0.0;
	for(int i = 1 + (o - 1); i< winLength; i += (p + 1))
	{
	    temp = temp + DF[ i ] * y[ i ]; 
	}
	align[ o ] = temp * weighting[ o ];       
    }


    double valTemp = 0.0;
    for(int i = 0; i < p; i++)
    {
	if( align[ i ] > valTemp )
	{
	    valTemp = align[ i ];
	    alignment = i;
	}
    }

    delete [] y;
    delete [] align;

    return alignment;
}

int TempoTrack::beatPredict(unsigned int FSP0, double alignment, double period, unsigned int step )
{
    int beat = 0;

    int p = (int)MathUtilities::round( period );
    int align = (int)MathUtilities::round( alignment );
    int FSP = (int)MathUtilities::round( FSP0 );

    int FEP = FSP + ( step );

    beat = FSP + align;

    m_beats.push_back( beat );

    while( beat + p < FEP )
    {
	beat += p;
		
	m_beats.push_back( beat );
    }

    return beat;
}



vector<int> TempoTrack::process( vector <double> DF,
                                 vector <double> *tempoReturn )
{
    m_dataLength = DF.size();
	
    m_lockedTempo = 0.0;

    double	period = 0.0;
    int stepFlag = 0;
    int constFlag = 0;
    int FSP = 0;
    int tsig = 0;
    int lastBeat = 0;

    vector <double> causalDF;

    causalDF = DF;

    //Prepare Causal Extension DFData
    unsigned int DFCLength = m_dataLength + m_winLength;
	
    for( unsigned int j = 0; j < m_winLength; j++ )
    {
	causalDF.push_back( 0 );
    }
	
	
    double* RW = new double[ m_lagLength ];
    for( unsigned int clear = 0; clear < m_lagLength; clear++){ RW[ clear ] = 0.0;}

    double* GW = new double[ m_lagLength ];
    for(unsigned int clear = 0; clear < m_lagLength; clear++){ GW[ clear ] = 0.0;}

    double* PW = new double[ m_lagLength ];
    for(unsigned clear = 0; clear < m_lagLength; clear++){ PW[ clear ] = 0.0;}

    m_DFFramer.setSource( &causalDF[0], m_dataLength );

    unsigned int TTFrames = m_DFFramer.getMaxNoFrames();

#ifdef DEBUG_TEMPO_TRACK
    std::cerr << "TTFrames = " << TTFrames << std::endl;
#endif
	
    double* periodP = new double[ TTFrames ];
    for(unsigned clear = 0; clear < TTFrames; clear++){ periodP[ clear ] = 0.0;}
	
    double* periodG = new double[ TTFrames ];
    for(unsigned clear = 0; clear < TTFrames; clear++){ periodG[ clear ] = 0.0;}
	
    double* alignment = new double[ TTFrames ];
    for(unsigned clear = 0; clear < TTFrames; clear++){ alignment[ clear ] = 0.0;}

    m_beats.clear();

    createCombFilter( RW, m_lagLength, 0, 0 );

    int TTLoopIndex = 0;

    for( unsigned int i = 0; i < TTFrames; i++ )
    {
	m_DFFramer.getFrame( m_rawDFFrame );

	m_DFConditioning->process( m_rawDFFrame, m_smoothDFFrame );

	m_correlator.doAutoUnBiased( m_smoothDFFrame, m_frameACF, m_winLength );
		
	periodP[ TTLoopIndex ] = tempoMM( m_frameACF, RW, 0 );

	if( GW[ 0 ] != 0 )
	{
	    periodG[ TTLoopIndex ] = tempoMM( m_frameACF, GW, tsig );
	}
	else
	{
	    periodG[ TTLoopIndex ] = 0.0;
	}

	stepDetect( periodP, periodG, TTLoopIndex, &stepFlag );

	if( stepFlag == 1)
	{
	    constDetect( periodP, TTLoopIndex, &constFlag );
	    stepFlag = 0;
	}
	else
	{
	    stepFlag -= 1;
	}

	if( stepFlag < 0 )
	{
	    stepFlag = 0;
	}

	if( constFlag != 0)
	{
	    tsig = findMeter( m_frameACF, m_winLength, periodP[ TTLoopIndex ] );
	
	    createCombFilter( GW, m_lagLength, tsig, periodP[ TTLoopIndex ] );
			
	    periodG[ TTLoopIndex ] = tempoMM( m_frameACF, GW, tsig ); 

	    period = periodG[ TTLoopIndex ];

#ifdef DEBUG_TEMPO_TRACK
            std::cerr << "TempoTrack::process: constFlag == " << constFlag << ", TTLoopIndex = " << TTLoopIndex << ", period from periodG = " << period << std::endl;
#endif

	    createPhaseExtractor( PW, m_winLength, period, FSP, 0 ); 

	    constFlag = 0;

	}
	else
	{
	    if( GW[ 0 ] != 0 )
	    {
		period = periodG[ TTLoopIndex ];

#ifdef DEBUG_TEMPO_TRACK
                std::cerr << "TempoTrack::process: GW[0] == " << GW[0] << ", TTLoopIndex = " << TTLoopIndex << ", period from periodG = " << period << std::endl;
#endif

                if (period > 10000) {
                    std::cerr << "TempoTrack::process: WARNING!  Highly implausible period value " << period << "!" << std::endl;
                    std::cerr << "periodG contains (of " << TTFrames << " frames): " << std::endl;
                    for (int i = 0; i < TTLoopIndex + 3 && i < TTFrames; ++i) {
                        std::cerr << i << " -> " << periodG[i] << std::endl;
                    }
                    std::cerr << "periodP contains (of " << TTFrames << " frames): " << std::endl;
                    for (int i = 0; i < TTLoopIndex + 3 && i < TTFrames; ++i) {
                        std::cerr << i << " -> " << periodP[i] << std::endl;
                    }
                    period = 5168 / 120;
                }

		createPhaseExtractor( PW, m_winLength, period, FSP, lastBeat ); 

	    }
	    else
	    {
		period = periodP[ TTLoopIndex ];

#ifdef DEBUG_TEMPO_TRACK
                std::cerr << "TempoTrack::process: GW[0] == " << GW[0] << ", TTLoopIndex = " << TTLoopIndex << ", period from periodP = " << period << std::endl;
#endif

		createPhaseExtractor( PW, m_winLength, period, FSP, 0 ); 
	    }
	}

	alignment[ TTLoopIndex ] = phaseMM( m_rawDFFrame, PW, m_winLength, period ); 

	lastBeat = beatPredict(FSP, alignment[ TTLoopIndex ], period, m_lagLength );

	FSP += (m_lagLength);

        if (tempoReturn) tempoReturn->push_back(m_lockedTempo);

	TTLoopIndex++;
    }


    delete [] periodP;
    delete [] periodG;
    delete [] alignment;

    delete [] RW;
    delete [] GW;
    delete [] PW;

    return m_beats;
}