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livetrax/libs/vamp-pyin/MonoPitchHMM.cpp

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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
pYIN - A fundamental frequency estimator for monophonic audio
Centre for Digital Music, Queen Mary, University of London.
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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 "MonoPitchHMM.h"
#include <boost/math/distributions.hpp>
#include <cstdio>
#include <cmath>
using std::vector;
using std::pair;
MonoPitchHMM::MonoPitchHMM() :
m_minFreq(61.735),
m_nBPS(5),
m_nPitch(0),
m_transitionWidth(0),
m_selfTrans(0.99),
m_yinTrust(.5),
m_freqs(0)
{
m_transitionWidth = 5*(m_nBPS/2) + 1;
m_nPitch = 69 * m_nBPS;
m_freqs = vector<double>(2*m_nPitch);
for (size_t iPitch = 0; iPitch < m_nPitch; ++iPitch)
{
m_freqs[iPitch] = m_minFreq * std::pow(2, iPitch * 1.0 / (12 * m_nBPS));
m_freqs[iPitch+m_nPitch] = -m_freqs[iPitch];
}
build();
}
const vector<double>
MonoPitchHMM::calculateObsProb(const vector<pair<double, double> > pitchProb)
{
vector<double> out = vector<double>(2*m_nPitch+1);
double probYinPitched = 0;
// BIN THE PITCHES
for (size_t iPair = 0; iPair < pitchProb.size(); ++iPair)
{
double freq = 440. * std::pow(2, (pitchProb[iPair].first - 69)/12);
if (freq <= m_minFreq) continue;
double d = 0;
double oldd = 1000;
for (size_t iPitch = 0; iPitch < m_nPitch; ++iPitch)
{
d = std::abs(freq-m_freqs[iPitch]);
if (oldd < d && iPitch > 0)
{
// previous bin must have been the closest
out[iPitch-1] = pitchProb[iPair].second;
probYinPitched += out[iPitch-1];
break;
}
oldd = d;
}
}
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double probReallyPitched = m_yinTrust * probYinPitched;
// std::cerr << probReallyPitched << " " << probYinPitched << std::endl;
// damn, I forget what this is all about...
for (size_t iPitch = 0; iPitch < m_nPitch; ++iPitch)
{
if (probYinPitched > 0) out[iPitch] *= (probReallyPitched/probYinPitched) ;
out[iPitch+m_nPitch] = (1 - probReallyPitched) / m_nPitch;
}
// out[2*m_nPitch] = m_yinTrust * (1 - probYinPitched);
return(out);
}
void
MonoPitchHMM::build()
{
// INITIAL VECTOR
init = vector<double>(2*m_nPitch, 1.0 / 2*m_nPitch);
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// TRANSITIONS
for (size_t iPitch = 0; iPitch < m_nPitch; ++iPitch)
{
int theoreticalMinNextPitch = static_cast<int>(iPitch)-static_cast<int>(m_transitionWidth/2);
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size_t minNextPitch = iPitch>m_transitionWidth/2 ? iPitch-m_transitionWidth/2 : 0;
size_t maxNextPitch = iPitch<m_nPitch-m_transitionWidth/2 ? iPitch+m_transitionWidth/2 : m_nPitch-1;
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// WEIGHT VECTOR
double weightSum = 0;
vector<double> weights;
for (size_t i = minNextPitch; i <= maxNextPitch; ++i)
{
if (i <= iPitch)
{
weights.push_back(i-theoreticalMinNextPitch+1);
// weights.push_back(i-theoreticalMinNextPitch+1+m_transitionWidth/2);
} else {
weights.push_back(iPitch-theoreticalMinNextPitch+1-(i-iPitch));
// weights.push_back(iPitch-theoreticalMinNextPitch+1-(i-iPitch)+m_transitionWidth/2);
}
weightSum += weights[weights.size()-1];
}
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// std::cerr << minNextPitch << " " << maxNextPitch << std::endl;
// TRANSITIONS TO CLOSE PITCH
for (size_t i = minNextPitch; i <= maxNextPitch; ++i)
{
from.push_back(iPitch);
to.push_back(i);
transProb.push_back(weights[i-minNextPitch] / weightSum * m_selfTrans);
from.push_back(iPitch);
to.push_back(i+m_nPitch);
transProb.push_back(weights[i-minNextPitch] / weightSum * (1-m_selfTrans));
from.push_back(iPitch+m_nPitch);
to.push_back(i+m_nPitch);
transProb.push_back(weights[i-minNextPitch] / weightSum * m_selfTrans);
// transProb.push_back(weights[i-minNextPitch] / weightSum * 0.5);
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from.push_back(iPitch+m_nPitch);
to.push_back(i);
transProb.push_back(weights[i-minNextPitch] / weightSum * (1-m_selfTrans));
// transProb.push_back(weights[i-minNextPitch] / weightSum * 0.5);
}
// TRANSITION TO UNVOICED
// from.push_back(iPitch+m_nPitch);
// to.push_back(2*m_nPitch);
// transProb.push_back(1-m_selfTrans);
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// TRANSITION FROM UNVOICED TO PITCH
// from.push_back(2*m_nPitch);
// to.push_back(iPitch+m_nPitch);
// transProb.push_back(1.0/m_nPitch);
}
// UNVOICED SELFTRANSITION
// from.push_back(2*m_nPitch);
// to.push_back(2*m_nPitch);
// transProb.push_back(m_selfTrans);
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// for (size_t i = 0; i < from.size(); ++i) {
// std::cerr << "P(["<< from[i] << " --> " << to[i] << "]) = " << transProb[i] << std::endl;
// }
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}