annotate CepstrumPitchTracker.cpp @ 25:9aee1a0e6223

Simplify confidence metric

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
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#include "CepstrumPitchTracker.h"

#include <vector>
#include <algorithm>

#include <cstdio>
#include <cmath>
#include <complex>

using std::string;
using std::vector;
using Vamp::RealTime;

CepstrumPitchTracker::Hypothesis::Hypothesis()
{
    m_state = New;
    m_age = 0;
}

CepstrumPitchTracker::Hypothesis::~Hypothesis()
{
}

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

    int lengthRequired = 10000;
    if (meanConfidence > 0.0) {
        lengthRequired = int(2.0 / meanConfidence + 0.5);
    }
    std::cerr << "meanConfidence = " << meanConfidence << ", lengthRequired = " << lengthRequired << ", length = " << m_pending.size() << std::endl;

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

void
CepstrumPitchTracker::Hypothesis::advanceTime()
{
    ++m_age;
}

bool
CepstrumPitchTracker::Hypothesis::test(Estimate s)
{
    bool accept = false;

    switch (m_state) {

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

    case Provisional:
        if (m_age > 3) {
            m_state = Rejected;
        } else if (isWithinTolerance(s)) {
            accept = true;
        }
        break;
        
    case Satisfied:
        if (m_age > 3) {
            m_state = Expired;
        } else if (isWithinTolerance(s)) {
            accept = true;
        }
        break;

    case Rejected:
        break;

    case Expired:
        break;
    }

    if (accept) {
        m_pending.push_back(s);
        m_age = 0;
        if (m_state == Provisional && isSatisfied()) {
            m_state = Satisfied;
        }
    }

    return accept && (m_state == Satisfied);
}        

CepstrumPitchTracker::Hypothesis::State
CepstrumPitchTracker::Hypothesis::getState()
{
    return m_state;
}

int
CepstrumPitchTracker::Hypothesis::getPendingLength()
{
    return m_pending.size();
}

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

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

CepstrumPitchTracker::Hypothesis::Note
CepstrumPitchTracker::Hypothesis::getAveragedNote()
{
    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::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;
}

void
CepstrumPitchTracker::Hypothesis::addFeatures(FeatureSet &fs)
{
    for (int i = 0; i < m_pending.size(); ++i) {
	Feature f;
	f.hasTimestamp = true;
	f.timestamp = m_pending[i].time;
	f.values.push_back(m_pending[i].freq);
	fs[0].push_back(f);
    }

    Feature nf;
    nf.hasTimestamp = true;
    nf.hasDuration = true;
    Note n = getAveragedNote();
    nf.timestamp = n.time;
    nf.duration = n.duration;
    nf.values.push_back(n.freq);
    fs[1].push_back(nf);
}

CepstrumPitchTracker::CepstrumPitchTracker(float inputSampleRate) :
    Plugin(inputSampleRate),
    m_channels(0),
    m_stepSize(256),
    m_blockSize(1024),
    m_fmin(50),
    m_fmax(900),
    m_vflen(1),
    m_binFrom(0),
    m_binTo(0),
    m_bins(0)
{
}

CepstrumPitchTracker::~CepstrumPitchTracker()
{
}

string
CepstrumPitchTracker::getIdentifier() const
{
    return "cepstrum-pitch";
}

string
CepstrumPitchTracker::getName() const
{
    return "Cepstrum Pitch Tracker";
}

string
CepstrumPitchTracker::getDescription() const
{
    return "Estimate f0 of monophonic material using a cepstrum method.";
}

string
CepstrumPitchTracker::getMaker() const
{
    return "Chris Cannam";
}

int
CepstrumPitchTracker::getPluginVersion() const
{
    // Increment this each time you release a version that behaves
    // differently from the previous one
    return 1;
}

string
CepstrumPitchTracker::getCopyright() const
{
    return "Freely redistributable (BSD license)";
}

CepstrumPitchTracker::InputDomain
CepstrumPitchTracker::getInputDomain() const
{
    return FrequencyDomain;
}

size_t
CepstrumPitchTracker::getPreferredBlockSize() const
{
    return 1024;
}

size_t 
CepstrumPitchTracker::getPreferredStepSize() const
{
    return 256;
}

size_t
CepstrumPitchTracker::getMinChannelCount() const
{
    return 1;
}

size_t
CepstrumPitchTracker::getMaxChannelCount() const
{
    return 1;
}

CepstrumPitchTracker::ParameterList
CepstrumPitchTracker::getParameterDescriptors() const
{
    ParameterList list;
    return list;
}

float
CepstrumPitchTracker::getParameter(string identifier) const
{
    return 0.f;
}

void
CepstrumPitchTracker::setParameter(string identifier, float value) 
{
}

CepstrumPitchTracker::ProgramList
CepstrumPitchTracker::getPrograms() const
{
    ProgramList list;
    return list;
}

string
CepstrumPitchTracker::getCurrentProgram() const
{
    return ""; // no programs
}

void
CepstrumPitchTracker::selectProgram(string name)
{
}

CepstrumPitchTracker::OutputList
CepstrumPitchTracker::getOutputDescriptors() const
{
    OutputList outputs;

    int n = 0;

    OutputDescriptor d;

    d.identifier = "f0";
    d.name = "Estimated f0";
    d.description = "Estimated fundamental frequency";
    d.unit = "Hz";
    d.hasFixedBinCount = true;
    d.binCount = 1;
    d.hasKnownExtents = true;
    d.minValue = m_fmin;
    d.maxValue = m_fmax;
    d.isQuantized = false;
    d.sampleType = OutputDescriptor::FixedSampleRate;
    d.sampleRate = (m_inputSampleRate / m_stepSize);
    d.hasDuration = false;
    outputs.push_back(d);

    d.identifier = "notes";
    d.name = "Notes";
    d.description = "Derived fixed-pitch note frequencies";
    d.unit = "Hz";
    d.hasFixedBinCount = true;
    d.binCount = 1;
    d.hasKnownExtents = true;
    d.minValue = m_fmin;
    d.maxValue = m_fmax;
    d.isQuantized = false;
    d.sampleType = OutputDescriptor::FixedSampleRate;
    d.sampleRate = (m_inputSampleRate / m_stepSize);
    d.hasDuration = true;
    outputs.push_back(d);

    return outputs;
}

bool
CepstrumPitchTracker::initialise(size_t channels, size_t stepSize, size_t blockSize)
{
    if (channels < getMinChannelCount() ||
	channels > getMaxChannelCount()) return false;

//    std::cerr << "CepstrumPitchTracker::initialise: channels = " << channels
//	      << ", stepSize = " << stepSize << ", blockSize = " << blockSize
//	      << std::endl;

    m_channels = channels;
    m_stepSize = stepSize;
    m_blockSize = blockSize;

    m_binFrom = int(m_inputSampleRate / m_fmax);
    m_binTo = int(m_inputSampleRate / m_fmin); 

    if (m_binTo >= (int)m_blockSize / 2) {
        m_binTo = m_blockSize / 2 - 1;
    }

    m_bins = (m_binTo - m_binFrom) + 1;

    reset();

    return true;
}

void
CepstrumPitchTracker::reset()
{
}

void
CepstrumPitchTracker::filter(const double *cep, double *data)
{
    for (int i = 0; i < m_bins; ++i) {
        double v = 0;
        int n = 0;
        // average according to the vertical filter length
        for (int j = -m_vflen/2; j <= m_vflen/2; ++j) {
            int ix = i + m_binFrom + j;
            if (ix >= 0 && ix < m_blockSize) {
                v += cep[ix];
                ++n;
            }
        }
        data[i] = v / n;
    }
}

double
CepstrumPitchTracker::cubicInterpolate(const double y[4], double x)
{
    double a0 = y[3] - y[2] - y[0] + y[1];
    double a1 = y[0] - y[1] - a0;
    double a2 = y[2] - y[0];
    double a3 = y[1];
    return
        a0 * x * x * x +
        a1 * x * x +
        a2 * x +
        a3;
}

double
CepstrumPitchTracker::findInterpolatedPeak(const double *in, int maxbin)
{
    if (maxbin < 2 || maxbin > m_bins - 3) {
        return maxbin;
    }

    double maxval = 0.0;
    double maxidx = maxbin;

    const int divisions = 10;
    double y[4];

    y[0] = in[maxbin-1];
    y[1] = in[maxbin];
    y[2] = in[maxbin+1];
    y[3] = in[maxbin+2];
    for (int i = 0; i < divisions; ++i) {
        double probe = double(i) / double(divisions);
        double value = cubicInterpolate(y, probe);
        if (value > maxval) {
            maxval = value; 
            maxidx = maxbin + probe;
        }
    }

    y[3] = y[2];
    y[2] = y[1];
    y[1] = y[0];
    y[0] = in[maxbin-2];
    for (int i = 0; i < divisions; ++i) {
        double probe = double(i) / double(divisions);
        double value = cubicInterpolate(y, probe);
        if (value > maxval) {
            maxval = value; 
            maxidx = maxbin - 1 + probe;
        }
    }

/*
    std::cerr << "centre = " << maxbin << ": ["
              << in[maxbin-2] << ","
              << in[maxbin-1] << ","
              << in[maxbin] << ","
              << in[maxbin+1] << ","
              << in[maxbin+2] << "] -> " << maxidx << std::endl;
*/

    return maxidx;
}

CepstrumPitchTracker::FeatureSet
CepstrumPitchTracker::process(const float *const *inputBuffers, RealTime timestamp)
{
    FeatureSet fs;

    int bs = m_blockSize;
    int hs = m_blockSize/2 + 1;

    double *rawcep = new double[bs];
    double *io = new double[bs];
    double *logmag = new double[bs];

    // The "inverse symmetric" method. Seems to be the most reliable
        
    double magmean = 0.0;

    for (int i = 0; i < hs; ++i) {

	double power =
	    inputBuffers[0][i*2  ] * inputBuffers[0][i*2  ] +
	    inputBuffers[0][i*2+1] * inputBuffers[0][i*2+1];
	double mag = sqrt(power);

        magmean += mag;

	double lm = log(mag + 0.00000001);
	
	logmag[i] = lm;
	if (i > 0) logmag[bs - i] = lm;
    }

    magmean /= hs;
    double threshold = 0.1; // for magmean
    
    fft(bs, true, logmag, 0, rawcep, io);
    
    delete[] logmag;
    delete[] io;

    int n = m_bins;
    double *data = new double[n];
    filter(rawcep, data);
    delete[] rawcep;

    double maxval = 0.0;
    int maxbin = -1;

    for (int i = 0; i < n; ++i) {
        if (data[i] > maxval) {
            maxval = data[i];
            maxbin = i;
        }
    }

    if (maxbin < 0) {
        delete[] data;
        return fs;
    }

    double nextPeakVal = 0.0;
    for (int i = 1; i+1 < n; ++i) {
        if (data[i] > data[i-1] &&
            data[i] > data[i+1] &&
            i != maxbin &&
            data[i] > nextPeakVal) {
            nextPeakVal = data[i];
        }
    }

    double cimax = findInterpolatedPeak(data, maxbin);
    double peakfreq = m_inputSampleRate / (cimax + m_binFrom);

    double confidence = 0.0;
    if (nextPeakVal != 0.0) {
        confidence = (maxval - nextPeakVal) / 100.0;
        if (magmean < threshold) confidence = 0.0;
        std::cerr << "magmean = " << magmean << ", confidence = " << confidence << std::endl;
    }

    Hypothesis::Estimate e;
    e.freq = peakfreq;
    e.time = timestamp;
    e.confidence = confidence;

    m_accepted.advanceTime();

    for (int i = 0; i < m_possible.size(); ++i) {
        m_possible[i].advanceTime();
    }

    if (!m_accepted.test(e)) {

        int candidate = -1;
        bool accepted = false;

        for (int i = 0; i < m_possible.size(); ++i) {
            if (m_possible[i].test(e)) {
                accepted = true;
                if (m_possible[i].getState() == Hypothesis::Satisfied) {
                    candidate = i;
                }
                break;
            }
        }

        if (!accepted) {
            Hypothesis h;
            h.test(e); //!!! must succeed as h is new, so perhaps there should be a ctor for this
            m_possible.push_back(h);
        }

        if (m_accepted.getState() == Hypothesis::Expired) {
            m_accepted.addFeatures(fs);
        }
        
        if (m_accepted.getState() == Hypothesis::Expired ||
            m_accepted.getState() == Hypothesis::Rejected) {
            if (candidate >= 0) {
                m_accepted = m_possible[candidate];
            } else {
                m_accepted = Hypothesis();
            }
        }

        // reap rejected/expired hypotheses from possible list
        Hypotheses toReap = m_possible;
        m_possible.clear();
        for (int i = 0; i < toReap.size(); ++i) {
            Hypothesis h = toReap[i];
            if (h.getState() != Hypothesis::Rejected && 
                h.getState() != Hypothesis::Expired) {
                m_possible.push_back(h);
            }
        }
    }  

    std::cerr << "accepted length = " << m_accepted.getPendingLength()
              << ", state = " << m_accepted.getState()
              << ", hypothesis count = " << m_possible.size() << std::endl;

    delete[] data;
    return fs;
}

CepstrumPitchTracker::FeatureSet
CepstrumPitchTracker::getRemainingFeatures()
{
    FeatureSet fs;
    if (m_accepted.getState() == Hypothesis::Satisfied) {
        m_accepted.addFeatures(fs);
    }
    return fs;
}

void
CepstrumPitchTracker::fft(unsigned int n, bool inverse,
                          double *ri, double *ii, double *ro, double *io)
{
    if (!ri || !ro || !io) return;

    unsigned int bits;
    unsigned int i, j, k, m;
    unsigned int blockSize, blockEnd;

    double tr, ti;

    if (n < 2) return;
    if (n & (n-1)) return;

    double angle = 2.0 * M_PI;
    if (inverse) angle = -angle;

    for (i = 0; ; ++i) {
	if (n & (1 << i)) {
	    bits = i;
	    break;
	}
    }

    int table[n];

    for (i = 0; i < n; ++i) {
        m = i;
        for (j = k = 0; j < bits; ++j) {
            k = (k << 1) | (m & 1);
            m >>= 1;
        }
        table[i] = k;
    }

    if (ii) {
	for (i = 0; i < n; ++i) {
	    ro[table[i]] = ri[i];
	    io[table[i]] = ii[i];
	}
    } else {
	for (i = 0; i < n; ++i) {
	    ro[table[i]] = ri[i];
	    io[table[i]] = 0.0;
	}
    }

    blockEnd = 1;

    for (blockSize = 2; blockSize <= n; blockSize <<= 1) {

	double delta = angle / (double)blockSize;
	double sm2 = -sin(-2 * delta);
	double sm1 = -sin(-delta);
	double cm2 = cos(-2 * delta);
	double cm1 = cos(-delta);
	double w = 2 * cm1;
	double ar[3], ai[3];

	for (i = 0; i < n; i += blockSize) {

	    ar[2] = cm2;
	    ar[1] = cm1;

	    ai[2] = sm2;
	    ai[1] = sm1;

	    for (j = i, m = 0; m < blockEnd; j++, m++) {

		ar[0] = w * ar[1] - ar[2];
		ar[2] = ar[1];
		ar[1] = ar[0];

		ai[0] = w * ai[1] - ai[2];
		ai[2] = ai[1];
		ai[1] = ai[0];

		k = j + blockEnd;
		tr = ar[0] * ro[k] - ai[0] * io[k];
		ti = ar[0] * io[k] + ai[0] * ro[k];

		ro[k] = ro[j] - tr;
		io[k] = io[j] - ti;

		ro[j] += tr;
		io[j] += ti;
	    }
	}

	blockEnd = blockSize;
    }
}