annotate dsp/tempotracking/TempoTrack.cpp @ 490:103156707542

Add cmath

/* -*- 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.

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#include "TempoTrack.h"

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

#include <iostream>

#include <cassert>
#include <cmath>

//#define DEBUG_TEMPO_TRACK 1

//////////////////////////////////////////////////////////////////////
// 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 ];

    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, int winLength, int /* TSig */, double beatLag)
{
    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(TWO_PI) * m_sigma);
        }
    }
}

double TempoTrack::tempoMM(double* ACF, double* weight, int tsig)
{
    double period = 0;
    double maxValRCF = 0.0;
    int maxIndexRCF = 0;

    double* pdPeaks;

    int maxIndexTemp;
    double maxValTemp;
    int count; 
        
    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, 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( 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, int /* winLength */, double period, int fsp, 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;
        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(TWO_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

        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, 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(int FSP0, double alignment, double period, 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
//    int DFCLength = m_dataLength + m_winLength;
        
    for( int j = 0; j < m_winLength; j++ ) {
        causalDF.push_back( 0 );
    }
        
        
    double* RW = new double[ m_lagLength ];
    for (int clear = 0; clear < m_lagLength; clear++){ RW[ clear ] = 0.0;}

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

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

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

    int TTFrames = m_DFFramer.getMaxNoFrames();

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

    m_beats.clear();

    createCombFilter( RW, m_lagLength, 0, 0 );

    int TTLoopIndex = 0;

    for( 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;
}