view devuvuzelator.cpp @ 4:d90abfa9585a

* Adaptive method

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

void
Devuvuzelator::processSpectralFrame()
{
    const int hs = m_fftsize/2 + 1;
    double *mags = (double *)alloca(hs * sizeof(double));
    double *ratios = (double *)alloca(hs * sizeof(double));
    for (int i = 0; i < hs; ++i) {
        ratios[i] = 1.0;
        mags[i] = sqrt(m_real[i] * m_real[i] + m_imag[i] * m_imag[i]);
    }

    double lowfun = m_fundamental - m_bandwidth/2;
    double highfun = m_fundamental + m_bandwidth/2;

    for (int h = 1; h <= m_harmonics; ++h) {

        double lowfreq = lowfun * h;
        double highfreq = highfun * h;

        int lowbin = 0.5 + (m_fftsize * lowfreq) / m_sampleRate;
        int highbin = 0.5 + (m_fftsize * highfreq) / m_sampleRate;

        for (int i = lowbin; i <= highbin; ++i) {

            if (!m_medians[i]) {
                const float filtersecs = 5.f;
                int filterlen = (filtersecs * m_sampleRate) / m_increment;
                m_medians[i] = new MedianFilter<double>(filterlen);
            }

            m_medians[i]->push(mags[i]);
            double threshold = m_medians[i]->getAt(m_reduction);
            if (mags[i] > threshold) {
                double target = mags[i] - threshold;
                ratios[i] = (target / mags[i]);
            } else {
                ratios[i] = 0.0;
            }
        }
    }

    for (int i = 0; i < hs; ++i) {
        m_real[i] *= ratios[i];
        m_imag[i] *= ratios[i];
    }
}