annotate ConstrainedHarmonicPeak.cpp @ 7:f5b9bae2a8c3

Copyrights etc

/*
    CHP
    Copyright (c) 2014 Queen Mary, University of London

    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 AUTHOR 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 "ConstrainedHarmonicPeak.h"

#include <cmath>
#include <cstdio>

using std::cerr;
using std::endl;
using std::vector;

ConstrainedHarmonicPeak::ConstrainedHarmonicPeak(float inputSampleRate) :
    Plugin(inputSampleRate),
    m_fftSize(0),
    m_minFreq(0),
    m_maxFreq(22050),
    m_harmonics(5)
{
}

ConstrainedHarmonicPeak::~ConstrainedHarmonicPeak()
{
}

string
ConstrainedHarmonicPeak::getIdentifier() const
{
    return "constrainedharmonicpeak";
}

string
ConstrainedHarmonicPeak::getName() const
{
    return "Frequency-Constrained Harmonic Peak";
}

string
ConstrainedHarmonicPeak::getDescription() const
{
    return "Return the interpolated peak frequency of a harmonic product spectrum within a given frequency range";
}

string
ConstrainedHarmonicPeak::getMaker() const
{
    return "Queen Mary, University of London";
}

int
ConstrainedHarmonicPeak::getPluginVersion() const
{
    return 1;
}

string
ConstrainedHarmonicPeak::getCopyright() const
{
    return "GPL";
}

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

size_t
ConstrainedHarmonicPeak::getPreferredBlockSize() const
{
    return 2048;
}

size_t 
ConstrainedHarmonicPeak::getPreferredStepSize() const
{
    return 512;
}

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

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

ConstrainedHarmonicPeak::ParameterList
ConstrainedHarmonicPeak::getParameterDescriptors() const
{
    ParameterList list;

    ParameterDescriptor d;
    d.identifier = "minfreq";
    d.name = "Minimum frequency";
    d.description = "Minimum frequency for peak finding. Will be rounded down to the nearest spectral bin.";
    d.unit = "Hz";
    d.minValue = 0;
    d.maxValue = m_inputSampleRate/2;
    d.defaultValue = 0;
    d.isQuantized = false;
    list.push_back(d);

    d.identifier = "maxfreq";
    d.name = "Maximum frequency";
    d.description = "Maximum frequency for peak finding. Will be rounded up to the nearest spectral bin.";
    d.unit = "Hz";
    d.minValue = 0;
    d.maxValue = m_inputSampleRate/2;
    d.defaultValue = 22050;
    d.isQuantized = false;
    list.push_back(d);

    d.identifier = "harmonics";
    d.name = "Harmonics";
    d.description = "Maximum number of harmonics to consider";
    d.unit = "";
    d.minValue = 1;
    d.maxValue = 20;
    d.defaultValue = 5;
    d.isQuantized = true;
    d.quantizeStep = 1;
    list.push_back(d);

    return list;
}

float
ConstrainedHarmonicPeak::getParameter(string identifier) const
{
    if (identifier == "minfreq") {
	return m_minFreq;
    } else if (identifier == "maxfreq") {
	return m_maxFreq;
    } else if (identifier == "harmonics") {
	return m_harmonics;
    }
    return 0;
}

void
ConstrainedHarmonicPeak::setParameter(string identifier, float value) 
{
    if (identifier == "minfreq") {
	m_minFreq = value;
    } else if (identifier == "maxfreq") {
	m_maxFreq = value;
    } else if (identifier == "harmonics") {
	m_harmonics = int(round(value));
    }
}

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

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

void
ConstrainedHarmonicPeak::selectProgram(string name)
{
}

ConstrainedHarmonicPeak::OutputList
ConstrainedHarmonicPeak::getOutputDescriptors() const
{
    OutputList list;

    OutputDescriptor d;
    d.identifier = "peak";
    d.name = "Peak frequency";
    d.description = "Interpolated frequency of the harmonic spectral peak within the given frequency range";
    d.unit = "Hz";
    d.sampleType = OutputDescriptor::OneSamplePerStep;
    d.hasDuration = false;
    list.push_back(d);

    return list;
}

bool
ConstrainedHarmonicPeak::initialise(size_t channels, size_t stepSize, size_t blockSize)
{
    if (channels < getMinChannelCount() ||
	channels > getMaxChannelCount()) {
	cerr << "ConstrainedHarmonicPeak::initialise: ERROR: channels " << channels
	     << " out of acceptable range " << getMinChannelCount()
	     << " -> " << getMaxChannelCount() << endl;
	return false;
    }

    m_fftSize = blockSize;

    return true;
}

void
ConstrainedHarmonicPeak::reset()
{
}

double
ConstrainedHarmonicPeak::findInterpolatedPeak(const double *in, 
					      int peakbin,
					      int bins)
{
    // duplicate with SimpleCepstrum plugin
    // after jos, 
    // https://ccrma.stanford.edu/~jos/sasp/Quadratic_Interpolation_Spectral_Peaks.html

    if (peakbin < 1 || peakbin > bins - 2) {
        return peakbin;
    }

    double alpha = in[peakbin-1];
    double beta  = in[peakbin];
    double gamma = in[peakbin+1];

    double denom = (alpha - 2*beta + gamma);

    if (denom == 0) {
        // flat
        return peakbin;
    }

    double p = ((alpha - gamma) / denom) / 2.0;

    return double(peakbin) + p;
}

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

    // This could be better. The procedure here is
    // 
    // 1 Produce a harmonic product spectrum within a limited
    //   frequency range by effectively summing the dB values of the
    //   bins at each multiple of the bin numbers (up to a given
    //   number of harmonics) in the range under consideration
    // 2 Find the peak bin
    // 3 Calculate the peak location by quadratic interpolation
    //   from the peak bin and its two neighbouring bins
    //
    // Problems with this: 
    //
    // 1 Harmonics might not be located at integer multiples of the
    //   original bin frequency
    // 2 Quadratic interpolation works "correctly" for dB-valued
    //   magnitude spectra but might not produce the right results in
    //   the dB-summed hps, especially in light of the first problem
    // 3 Interpolation might not make sense at all if there are
    //   multiple nearby frequencies interfering across the three
    //   bins used for interpolation (we may be unable to identify
    //   the right frequency at all, but it's possible interpolation
    //   will make our guess worse rather than better)
    //
    // Possible improvements:
    // 
    // 1 Find the higher harmonics by looking for the peak bin within
    //   a range around the nominal peak location
    // 2 Once a peak has been identified as the peak of the HPS, use
    //   the original spectrum (not the HPS) to obtain the values for
    //   interpolation? (would help with problem 2 but might make
    //   problem 3 worse)

    int hs = m_fftSize/2;

    double *mags = new double[hs+1];
    for (int i = 0; i <= hs; ++i) {
	mags[i] = sqrt(inputBuffers[0][i*2] * inputBuffers[0][i*2] +
		       inputBuffers[0][i*2+1] * inputBuffers[0][i*2+1]);
    }

    // bin freq is bin * samplerate / fftsize

    int minbin = int(floor((m_minFreq * m_fftSize) / m_inputSampleRate));
    int maxbin = int(ceil((m_maxFreq * m_fftSize) / m_inputSampleRate));
    if (minbin > hs) minbin = hs;
    if (maxbin > hs) maxbin = hs;
    if (maxbin <= minbin) return fs;

    double *hps = new double[maxbin - minbin + 1];

    // HPS in dB after MzHarmonicSpectrum

    for (int bin = minbin; bin <= maxbin; ++bin) {

	int i = bin - minbin;
	hps[i] = 1.0;

	int contributing = 0;

	for (int j = 1; j <= m_harmonics; ++j) {
	    if (j * bin > hs) break;
	    hps[i] *= mags[j * bin];
	    ++contributing;
	}

	if (hps[i] <= 0.0) {
	    hps[i] = -120.0;
	} else {
	    hps[i] = 20.0 / contributing * log10(hps[i]);
	}
    }

    double maxdb = -120.0;
    int maxidx = 0;
    for (int i = 0; i <= maxbin - minbin; ++i) {
	if (hps[i] > maxdb) {
	    maxdb = hps[i];
	    maxidx = i;
	}
    }

    double interpolated = findInterpolatedPeak(hps, maxidx, maxbin - minbin + 1);
    interpolated = interpolated + minbin;

    double freq = interpolated * m_inputSampleRate / m_fftSize;

    Feature f;
    f.values.push_back(freq);
    fs[0].push_back(f);

    return fs;
}

ConstrainedHarmonicPeak::FeatureSet
ConstrainedHarmonicPeak::getRemainingFeatures()
{
    FeatureSet fs;
    return fs;
}