Cepstral Pitch Tracker

    m_history(0),

    m_prevpeak(0),

    m_prevprop(0)

double

CepstrumPitchTracker::calculatePeakProportion(const double *data, double abstot, int n)

{

    double aroundPeak = data[n];

    double peakProportion = 0.0;

    int i = n - 1;

    while (i > 0 && data[i] <= data[i+1]) {

        aroundPeak += fabs(data[i]);

        --i;

    }

    i = n + 1;

    while (i < m_bins && data[i] <= data[i-1]) {

        aroundPeak += fabs(data[i]);

        ++i;

    }

    peakProportion = aroundPeak / abstot;

    return peakProportion;

}

bool

CepstrumPitchTracker::acceptPeak(int n, double peakProportion)

{

    bool accept = false;

    if (abs(n - m_prevpeak) < 10) { //!!! should depend on bin count

        accept = true;

    } else if (peakProportion > m_prevprop * 2) {

        accept = true;

    }

    return accept;

}

    double abstot = 0.0;

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

	abstot += fabs(data[i]);

    }

    int maxbin = -1;

    bool accepted = false;

    if (maxbin >= 0) {

        double pp = calculatePeakProportion(data, abstot, maxbin);

        if (acceptPeak(maxbin, pp)) {

            accepted = true;

        } else {

            // try a secondary peak

            maxval = 0.0;

            int secondbin = 0;

            for (int i = 1; i < n-1; ++i) {

                if (i != maxbin &&

                    data[i] > data[i-1] &&

                    data[i] > data[i+1] &&

                    data[i] > maxval) {

                    maxval = data[i];

                    secondbin = i;

                }

            }

            double spp = calculatePeakProportion(data, abstot, secondbin);

            if (acceptPeak(secondbin, spp)) {

                maxbin = secondbin;

                pp = spp;

                accepted = true;

            }

        if (accepted) {

            m_prevpeak = maxbin;

            m_prevprop = pp;

//    if (peakProportion >= (0.00006 * m_bins)) {

    if (accepted) {