annotate NoteHypothesis.cpp @ 75:84d1a0647ce5 tip

Split out COPYING from README

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
/*
    This file is Copyright (c) 2012 Chris Cannam
  
    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the "Software"), to deal in the Software without
    restriction, including without limitation the rights to use, copy,
    modify, merge, publish, distribute, sublicense, and/or sell copies
    of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
    ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#include "NoteHypothesis.h"

#include <cmath>

using Vamp::RealTime;

NoteHypothesis::NoteHypothesis()
{
    m_state = New;
}

NoteHypothesis::~NoteHypothesis()
{
}

bool
NoteHypothesis::isWithinTolerance(Estimate s) const
{
    if (m_pending.empty()) {
        return true;
    }

    // check we are within a relatively close tolerance of the last
    // candidate
    Estimate last = m_pending[m_pending.size()-1];
    double r = s.freq / last.freq;
    int cents = lrint(1200.0 * (log(r) / log(2.0)));
    if (cents < -60 || cents > 60) return false;

    // and within a slightly bigger tolerance of the current mean
    double meanFreq = getMeanFrequency();
    r = s.freq / meanFreq;
    cents = lrint(1200.0 * (log(r) / log(2.0)));
    if (cents < -80 || cents > 80) return false;
    
    return true;
}

bool
NoteHypothesis::isOutOfDateFor(Estimate s) const
{
    if (m_pending.empty()) return false;
    return ((s.time - m_pending[m_pending.size()-1].time) > 
            RealTime::fromMilliseconds(40));
}

bool 
NoteHypothesis::isSatisfied() const
{
    if (m_pending.empty()) return false;
    
    double meanConfidence = 0.0;
    for (int i = 0; i < (int)m_pending.size(); ++i) {
        meanConfidence += m_pending[i].confidence;
    }
    meanConfidence /= m_pending.size();

    int lengthRequired = 100;
    if (meanConfidence > 0.0) {
        lengthRequired = int(2.0 / meanConfidence + 0.5);
    }

    return ((int)m_pending.size() > lengthRequired);
}

bool
NoteHypothesis::accept(Estimate s)
{
    bool accept = false;

    static double negligibleConfidence = 0.0001;

    if (s.confidence < negligibleConfidence) {
        // avoid piling up a lengthy sequence of estimates that are
        // all acceptable but are in total not enough to cause us to
        // be satisfied
        if (m_pending.empty()) {
            m_state = Rejected;
        }
        return false;
    }

    switch (m_state) {

    case New:
        m_state = Provisional;
        accept = true;
        break;

    case Provisional:
        if (isOutOfDateFor(s)) {
            m_state = Rejected;
        } else if (isWithinTolerance(s)) {
            accept = true;
        }
        break;
        
    case Satisfied:
        if (isOutOfDateFor(s)) {
            m_state = Expired;
        } else if (isWithinTolerance(s)) {
            accept = true;
        }
        break;

    case Rejected:
        break;

    case Expired:
        break;
    }

    if (accept) {
        m_pending.push_back(s);
        if (m_state == Provisional && isSatisfied()) {
            m_state = Satisfied;
        }
    }

    return accept;
}        

NoteHypothesis::State
NoteHypothesis::getState() const
{
    return m_state;
}

NoteHypothesis::Estimates
NoteHypothesis::getAcceptedEstimates() const
{
    if (m_state == Satisfied || m_state == Expired) {
        return m_pending;
    } else {
        return Estimates();
    }
}

RealTime
NoteHypothesis::getStartTime() const
{
    if (!(m_state == Satisfied || m_state == Expired)) {
        return RealTime::zeroTime;
    } else {
        return m_pending.begin()->time;
    }
}

double
NoteHypothesis::getMeanFrequency() const
{
    double acc = 0.0;
    if (m_pending.empty()) return acc;
    for (int i = 0; i < (int)m_pending.size(); ++i) {
        acc += m_pending[i].freq;
    }
    acc /= m_pending.size();
    return acc;
}

NoteHypothesis::Note
NoteHypothesis::getAveragedNote() const
{
    Note n;

    if (!(m_state == Satisfied || m_state == Expired)) {
        n.freq = 0.0;
        n.time = RealTime::zeroTime;
        n.duration = RealTime::zeroTime;
        return n;
    }

    n.time = m_pending.begin()->time;

    Estimates::const_iterator i = m_pending.end();
    --i;
    n.duration = i->time - n.time;

    // just mean frequency for now, but this isn't at all right perceptually
    n.freq = getMeanFrequency();
    
    return n;
}