view devuvuzelator.cpp @ 1:0d2126c32309

* split out core code, fix some things

/* -*- 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 low = -35;
    double high = -20;

    if (m_low) low = *m_low;
    if (m_high) high = *m_high;

    int harmonics = 3;
    if (m_harmonics) harmonics = int(*m_harmonics + 0.5);

    double fun = 200;
    if (m_fundamental) fun = *m_fundamental;

    double bw = 40;
    if (m_bandwidth) bw = *m_bandwidth;
        
    double lowfun = fun - bw/2;
    double highfun = fun + bw/2;

    double reduction = 10;
    if (m_reduction) reduction = *m_reduction;

    for (int h = 1; h <= 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;

//        std::cerr << "partials " << h << ": freqs " << lowfreq << "->"
//                  << highfreq << ", bins " << lowbin << "->"  << highbin << std::endl;

        for (int i = lowbin; i <= highbin; ++i) {
//            std::cerr << "bin " << i << " freq " << (m_sampleRate * i) / m_fftsize << std::endl;
            ratios[i] = 1.0;
            double db = 10 * log10(mags[i]);
            if (db > low && db < high) {
                double r = reduction;
                ratios[i] = pow(10, -r / 10);
            }
        }
    }
/*
    for (int i = 0; i < hs-1; ++i) {
        if (ratios[i] == 1.0 && ratios[i+1] < 1.0) {
            ratios[i] = (ratios[i+1] + 1) / 2;
        } else if (ratios[i] < 1.0 && ratios[i+1] == 1.0) {
            ratios[i+1] = (ratios[i] + 1) / 2;
            ++i;
        }
    }
*/
    for (int i = 0; i < hs; ++i) {
        m_real[i] *= ratios[i];
        m_imag[i] *= ratios[i];
    }
}