Paul Davis
3deba1921b
git-svn-id: svn://localhost/ardour2/branches/3.0@9029 d708f5d6-7413-0410-9779-e7cbd77b26cf
488 lines
13 KiB
C++
488 lines
13 KiB
C++
/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
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/*
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QM DSP Library
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Centre for Digital Music, Queen Mary, University of London.
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This file copyright 2008-2009 Matthew Davies and QMUL.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version. See the file
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COPYING included with this distribution for more information.
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*/
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#include "TempoTrackV2.h"
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#include <cmath>
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#include <cstdlib>
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#include <iostream>
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#include "maths/MathUtilities.h"
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#define EPS 0.0000008 // just some arbitrary small number
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TempoTrackV2::TempoTrackV2(float rate, size_t increment) :
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m_rate(rate), m_increment(increment) { }
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TempoTrackV2::~TempoTrackV2() { }
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void
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TempoTrackV2::filter_df(d_vec_t &df)
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{
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d_vec_t a(3);
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d_vec_t b(3);
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d_vec_t lp_df(df.size());
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//equivalent in matlab to [b,a] = butter(2,0.4);
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a[0] = 1.0000;
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a[1] = -0.3695;
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a[2] = 0.1958;
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b[0] = 0.2066;
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b[1] = 0.4131;
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b[2] = 0.2066;
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double inp1 = 0.;
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double inp2 = 0.;
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double out1 = 0.;
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double out2 = 0.;
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// forwards filtering
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for (unsigned int i = 0;i < df.size();i++)
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{
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lp_df[i] = b[0]*df[i] + b[1]*inp1 + b[2]*inp2 - a[1]*out1 - a[2]*out2;
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inp2 = inp1;
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inp1 = df[i];
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out2 = out1;
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out1 = lp_df[i];
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}
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// copy forwards filtering to df...
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// but, time-reversed, ready for backwards filtering
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for (unsigned int i = 0;i < df.size();i++)
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{
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df[i] = lp_df[df.size()-i-1];
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}
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for (unsigned int i = 0;i < df.size();i++)
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{
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lp_df[i] = 0.;
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}
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inp1 = 0.; inp2 = 0.;
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out1 = 0.; out2 = 0.;
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// backwards filetering on time-reversed df
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for (unsigned int i = 0;i < df.size();i++)
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{
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lp_df[i] = b[0]*df[i] + b[1]*inp1 + b[2]*inp2 - a[1]*out1 - a[2]*out2;
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inp2 = inp1;
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inp1 = df[i];
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out2 = out1;
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out1 = lp_df[i];
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}
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// write the re-reversed (i.e. forward) version back to df
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for (unsigned int i = 0;i < df.size();i++)
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{
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df[i] = lp_df[df.size()-i-1];
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}
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}
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void
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TempoTrackV2::calculateBeatPeriod(const vector<double> &df,
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vector<double> &beat_period,
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vector<double> &tempi)
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{
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// to follow matlab.. split into 512 sample frames with a 128 hop size
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// calculate the acf,
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// then the rcf.. and then stick the rcfs as columns of a matrix
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// then call viterbi decoding with weight vector and transition matrix
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// and get best path
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unsigned int wv_len = 128;
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double rayparam = 43.;
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// make rayleigh weighting curve
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d_vec_t wv(wv_len);
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for (unsigned int i=0; i<wv.size(); i++)
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{
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wv[i] = (static_cast<double> (i) / pow(rayparam,2.)) * exp((-1.*pow(-static_cast<double> (i),2.)) / (2.*pow(rayparam,2.)));
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}
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// beat tracking frame size (roughly 6 seconds) and hop (1.5 seconds)
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unsigned int winlen = 512;
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unsigned int step = 128;
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// matrix to store output of comb filter bank, increment column of matrix at each frame
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d_mat_t rcfmat;
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int col_counter = -1;
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// main loop for beat period calculation
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for (unsigned int i=0; i+winlen<df.size(); i+=step)
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{
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// get dfframe
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d_vec_t dfframe(winlen);
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for (unsigned int k=0; k<winlen; k++)
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{
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dfframe[k] = df[i+k];
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}
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// get rcf vector for current frame
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d_vec_t rcf(wv_len);
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get_rcf(dfframe,wv,rcf);
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rcfmat.push_back( d_vec_t() ); // adds a new column
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col_counter++;
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for (unsigned int j=0; j<rcf.size(); j++)
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{
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rcfmat[col_counter].push_back( rcf[j] );
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}
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}
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// now call viterbi decoding function
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viterbi_decode(rcfmat,wv,beat_period,tempi);
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}
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void
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TempoTrackV2::get_rcf(const d_vec_t &dfframe_in, const d_vec_t &wv, d_vec_t &rcf)
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{
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// calculate autocorrelation function
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// then rcf
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// just hard code for now... don't really need separate functions to do this
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// make acf
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d_vec_t dfframe(dfframe_in);
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MathUtilities::adaptiveThreshold(dfframe);
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d_vec_t acf(dfframe.size());
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for (unsigned int lag=0; lag<dfframe.size(); lag++)
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{
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double sum = 0.;
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double tmp = 0.;
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for (unsigned int n=0; n<(dfframe.size()-lag); n++)
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{
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tmp = dfframe[n] * dfframe[n+lag];
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sum += tmp;
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}
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acf[lag] = static_cast<double> (sum/ (dfframe.size()-lag));
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}
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// now apply comb filtering
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int numelem = 4;
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for (unsigned int i = 2;i < rcf.size();i++) // max beat period
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{
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for (int a = 1;a <= numelem;a++) // number of comb elements
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{
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for (int b = 1-a;b <= a-1;b++) // general state using normalisation of comb elements
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{
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rcf[i-1] += ( acf[(a*i+b)-1]*wv[i-1] ) / (2.*a-1.); // calculate value for comb filter row
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}
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}
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}
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// apply adaptive threshold to rcf
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MathUtilities::adaptiveThreshold(rcf);
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double rcfsum =0.;
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for (unsigned int i=0; i<rcf.size(); i++)
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{
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rcf[i] += EPS ;
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rcfsum += rcf[i];
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}
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// normalise rcf to sum to unity
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for (unsigned int i=0; i<rcf.size(); i++)
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{
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rcf[i] /= (rcfsum + EPS);
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}
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}
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void
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TempoTrackV2::viterbi_decode(const d_mat_t &rcfmat, const d_vec_t &wv, d_vec_t &beat_period, d_vec_t &tempi)
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{
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// following Kevin Murphy's Viterbi decoding to get best path of
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// beat periods through rfcmat
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// make transition matrix
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d_mat_t tmat;
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for (unsigned int i=0;i<wv.size();i++)
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{
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tmat.push_back ( d_vec_t() ); // adds a new column
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for (unsigned int j=0; j<wv.size(); j++)
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{
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tmat[i].push_back(0.); // fill with zeros initially
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}
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}
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// variance of Gaussians in transition matrix
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// formed of Gaussians on diagonal - implies slow tempo change
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double sigma = 8.;
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// don't want really short beat periods, or really long ones
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for (unsigned int i=20;i <wv.size()-20; i++)
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{
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for (unsigned int j=20; j<wv.size()-20; j++)
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{
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double mu = static_cast<double>(i);
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tmat[i][j] = exp( (-1.*pow((j-mu),2.)) / (2.*pow(sigma,2.)) );
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}
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}
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// parameters for Viterbi decoding... this part is taken from
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// Murphy's matlab
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d_mat_t delta;
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i_mat_t psi;
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for (unsigned int i=0;i <rcfmat.size(); i++)
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{
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delta.push_back( d_vec_t());
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psi.push_back( i_vec_t());
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for (unsigned int j=0; j<rcfmat[i].size(); j++)
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{
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delta[i].push_back(0.); // fill with zeros initially
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psi[i].push_back(0); // fill with zeros initially
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}
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}
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unsigned int T = delta.size();
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if (T < 2) return; // can't do anything at all meaningful
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unsigned int Q = delta[0].size();
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// initialize first column of delta
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for (unsigned int j=0; j<Q; j++)
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{
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delta[0][j] = wv[j] * rcfmat[0][j];
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psi[0][j] = 0;
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}
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double deltasum = 0.;
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for (unsigned int i=0; i<Q; i++)
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{
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deltasum += delta[0][i];
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}
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for (unsigned int i=0; i<Q; i++)
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{
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delta[0][i] /= (deltasum + EPS);
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}
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for (unsigned int t=1; t<T; t++)
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{
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d_vec_t tmp_vec(Q);
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for (unsigned int j=0; j<Q; j++)
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{
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for (unsigned int i=0; i<Q; i++)
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{
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tmp_vec[i] = delta[t-1][i] * tmat[j][i];
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}
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delta[t][j] = get_max_val(tmp_vec);
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psi[t][j] = get_max_ind(tmp_vec);
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delta[t][j] *= rcfmat[t][j];
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}
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// normalise current delta column
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double deltasum = 0.;
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for (unsigned int i=0; i<Q; i++)
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{
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deltasum += delta[t][i];
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}
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for (unsigned int i=0; i<Q; i++)
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{
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delta[t][i] /= (deltasum + EPS);
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}
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}
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i_vec_t bestpath(T);
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d_vec_t tmp_vec(Q);
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for (unsigned int i=0; i<Q; i++)
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{
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tmp_vec[i] = delta[T-1][i];
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}
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// find starting point - best beat period for "last" frame
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bestpath[T-1] = get_max_ind(tmp_vec);
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// backtrace through index of maximum values in psi
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for (unsigned int t=T-2; t>0 ;t--)
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{
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bestpath[t] = psi[t+1][bestpath[t+1]];
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}
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// weird but necessary hack -- couldn't get above loop to terminate at t >= 0
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bestpath[0] = psi[1][bestpath[1]];
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unsigned int lastind = 0;
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for (unsigned int i=0; i<T; i++)
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{
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unsigned int step = 128;
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for (unsigned int j=0; j<step; j++)
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{
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lastind = i*step+j;
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beat_period[lastind] = bestpath[i];
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}
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// std::cerr << "bestpath[" << i << "] = " << bestpath[i] << " (used for beat_periods " << i*step << " to " << i*step+step-1 << ")" << std::endl;
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}
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//fill in the last values...
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for (unsigned int i=lastind; i<beat_period.size(); i++)
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{
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beat_period[i] = beat_period[lastind];
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}
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for (unsigned int i = 0; i < beat_period.size(); i++)
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{
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tempi.push_back((60. * m_rate / m_increment)/beat_period[i]);
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}
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}
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double
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TempoTrackV2::get_max_val(const d_vec_t &df)
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{
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double maxval = 0.;
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for (unsigned int i=0; i<df.size(); i++)
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{
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if (maxval < df[i])
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{
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maxval = df[i];
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}
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}
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return maxval;
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}
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int
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TempoTrackV2::get_max_ind(const d_vec_t &df)
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{
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double maxval = 0.;
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int ind = 0;
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for (unsigned int i=0; i<df.size(); i++)
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{
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if (maxval < df[i])
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{
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maxval = df[i];
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ind = i;
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}
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}
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return ind;
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}
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void
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TempoTrackV2::normalise_vec(d_vec_t &df)
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{
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double sum = 0.;
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for (unsigned int i=0; i<df.size(); i++)
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{
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sum += df[i];
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}
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for (unsigned int i=0; i<df.size(); i++)
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{
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df[i]/= (sum + EPS);
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}
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}
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void
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TempoTrackV2::calculateBeats(const vector<double> &df,
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const vector<double> &beat_period,
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vector<double> &beats)
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{
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if (df.empty() || beat_period.empty()) return;
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d_vec_t cumscore(df.size()); // store cumulative score
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i_vec_t backlink(df.size()); // backlink (stores best beat locations at each time instant)
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d_vec_t localscore(df.size()); // localscore, for now this is the same as the detection function
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for (unsigned int i=0; i<df.size(); i++)
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{
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localscore[i] = df[i];
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backlink[i] = -1;
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}
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double tightness = 4.;
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double alpha = 0.9;
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// main loop
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for (unsigned int i=0; i<localscore.size(); i++)
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{
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int prange_min = -2*beat_period[i];
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int prange_max = round(-0.5*beat_period[i]);
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// transition range
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d_vec_t txwt (prange_max - prange_min + 1);
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d_vec_t scorecands (txwt.size());
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for (unsigned int j=0;j<txwt.size();j++)
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{
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double mu = static_cast<double> (beat_period[i]);
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txwt[j] = exp( -0.5*pow(tightness * log((round(2*mu)-j)/mu),2));
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// IF IN THE ALLOWED RANGE, THEN LOOK AT CUMSCORE[I+PRANGE_MIN+J
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// ELSE LEAVE AT DEFAULT VALUE FROM INITIALISATION: D_VEC_T SCORECANDS (TXWT.SIZE());
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int cscore_ind = i+prange_min+j;
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if (cscore_ind >= 0)
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{
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scorecands[j] = txwt[j] * cumscore[cscore_ind];
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}
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}
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// find max value and index of maximum value
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double vv = get_max_val(scorecands);
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int xx = get_max_ind(scorecands);
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cumscore[i] = alpha*vv + (1.-alpha)*localscore[i];
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backlink[i] = i+prange_min+xx;
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// std::cerr << "backlink[" << i << "] <= " << backlink[i] << std::endl;
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}
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// STARTING POINT, I.E. LAST BEAT.. PICK A STRONG POINT IN cumscore VECTOR
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d_vec_t tmp_vec;
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for (unsigned int i=cumscore.size() - beat_period[beat_period.size()-1] ; i<cumscore.size(); i++)
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{
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tmp_vec.push_back(cumscore[i]);
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}
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int startpoint = get_max_ind(tmp_vec) + cumscore.size() - beat_period[beat_period.size()-1] ;
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// can happen if no results obtained earlier (e.g. input too short)
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if (startpoint >= backlink.size()) startpoint = backlink.size()-1;
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// USE BACKLINK TO GET EACH NEW BEAT (TOWARDS THE BEGINNING OF THE FILE)
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// BACKTRACKING FROM THE END TO THE BEGINNING.. MAKING SURE NOT TO GO BEFORE SAMPLE 0
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i_vec_t ibeats;
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ibeats.push_back(startpoint);
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// std::cerr << "startpoint = " << startpoint << std::endl;
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while (backlink[ibeats.back()] > 0)
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{
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// std::cerr << "backlink[" << ibeats.back() << "] = " << backlink[ibeats.back()] << std::endl;
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int b = ibeats.back();
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if (backlink[b] == b) break; // shouldn't happen... haha
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ibeats.push_back(backlink[b]);
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}
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// REVERSE SEQUENCE OF IBEATS AND STORE AS BEATS
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for (unsigned int i=0; i<ibeats.size(); i++)
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{
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beats.push_back( static_cast<double>(ibeats[ibeats.size()-i-1]) );
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}
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}
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