annotate devuvuzelator-vst.cpp @ 0:fe4c331213c5

* First cut at a devuvuzelator

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

#include <alloca.h>
#include <iostream>
#include <cmath>

#include <vst2.x/audioeffect.h>

#define FFTSIZE 1024

class Devuvuzelator : public AudioEffect
{
    enum {
        LowParam       = 0,
        HighParam      = 1,
        FundamentalParam = 2,
        BandwidthParam = 3,
        HarmonicsParam = 4,
        ReductionParam = 5,
        NumParams      = 6
    };

public:
    Devuvuzelator(audioMasterCallback cb);
    ~Devuvuzelator();

    virtual void getEffectName(char *n) {
        vst_strncpy(n, "Devuvuzelator", kVstMaxEffectNameLen);
    }
    virtual void getProductString(char *n) {
        vst_strncpy(n, "Devuvuzelator", kVstMaxProductStrLen);
    }
    virtual void getVendorString(char *n) {
        vst_strncpy(n, "Queen Mary, University of London", kVstMaxVendorStrLen);
    }

    virtual void setParameter(VstInt32 index, float value);
    virtual float getParameter(VstInt32 index);
    virtual void getParameterLabel(VstInt32 index, char* label);
    virtual void getParameterDisplay(VstInt32 index, char* text);
    virtual void getParameterName(VstInt32 index, char* text);
    
    virtual void setSampleRate (float sampleRate) {
        m_sampleRate = sampleRate;
        AudioEffect::setSampleRate(sampleRate);
    }

    virtual void processReplacing (float** inputs, float** outputs, VstInt32 sampleFrames) {
        m_input = inputs[0];
        m_output = outputs[0];
        runImpl(sampleFrames);
    }

    void reset();
    void window(float *);
    void runImpl(unsigned long);
    void processFrame();
    void processSpectralFrame();

    static void fft(unsigned int n, bool inverse,
                    double *ri, double *ii, double *ro, double *io);

    int m_sampleRate;
    float *m_input;
    float *m_output;

    float m_high;
    float m_low;
    float m_fundamental;
    float m_bandwidth;
    float m_harmonics;
    float m_reduction;

    const int m_fftsize;
    const int m_increment;
    int m_fill;
    int m_read;
    float *m_buffer;
    float *m_outacc;
    double *m_real;
    double *m_imag;
    double *m_window;
};

void
Devuvuzelator::setParameter(VstInt32 index, float value)
{
    float *params[NumParams] = {
        m_low,
        m_high,
        m_fundamental,
        m_bandwidth,
        m_harmonics,
        m_reduction,
    };

    *params[index] = value;
}

float
Devuvuzelator::getParameter(VstInt32 index)
{
    float *params[NumParams] = {
        m_low,
        m_high,
        m_fundamental,
        m_bandwidth,
        m_harmonics,
        m_reduction,
    };

    return *params[index];
}

// NB! The max name length for VST parameter names, labels
// (i.e. units) and display values (i.e. string renderings of current
// value) is a rather amazing 8 bytes

void
Devuvuzelator::getParameterLabel(VstInt32 index, char *label)
{
    const char *units[NumParams] = {
        "dB",
        "dB",
        "Hz",
        "Hz",
        "",
        "dB",
    };
    
    vst_strncpy(label, units[index], kVstMaxParamStrLen);
}

void
Devuvuzelator::getParameterDisplay(VstInt32 index, char *label)
{
    snprintf(label, kVstMaxParamStrLen, "%f", getParameter(index));
}

void
Devuvuzelator::getParameterName(VstInt32 index, char *label)
{
    const char *names[NumParams] = {
        "Floor",
        "Ceiling",
        "Pitch",
        "B/W",
        "Partials",
        "Reductn",
    };
    
    vst_strncpy(label, names[index], kVstMaxParamStrLen);
}

Devuvuzelator::Devuvuzelator(audioMasterCallback cb) :
    AudioEffect(cb, 0, NumParams),
    m_sampleRate(0),
    m_input(0),
    m_output(0),
    m_low(0),
    m_high(0),
    m_fftsize(FFTSIZE),
    m_increment(m_fftsize/4),
    m_fill(0),
    m_read(0)
{
    m_buffer = new float[m_fftsize];
    m_outacc = new float[m_fftsize * 2];
    m_real = new double[m_fftsize];
    m_imag = new double[m_fftsize];
    m_window = new double[m_fftsize];

    for (int i = 0; i < m_fftsize; ++i) {
        m_window[i] = 0.5 - 0.5 * cos(2 * M_PI * i / m_fftsize);
    }

    m_low = -40;
    m_high = -20;
    m_fundamental = 220;
    m_bandwidth = 60;
    m_harmonics = 3;
    m_reduction = 10;
    
    setUniqueID("qmvz");
    setNumInputs(1);
    setNumOutputs(1);
    canProcessReplacing(true);
    canDoubleReplacing(false);

    reset();
}

Devuvuzelator::~Devuvuzelator()
{
    delete[] m_buffer;
    delete[] m_outacc;
    delete[] m_real;
    delete[] m_imag;
    delete[] m_window;
}

void
Devuvuzelator::reset()
{
    for (int i = 0; i < m_fftsize; ++i) {
        m_buffer[i] = 0.f;
    }
    for (int i = 0; i < m_fftsize*2; ++i) {
        m_outacc[i] = 0.f;
    }
    m_fill = 0;
    m_read = 0;
}

void
Devuvuzelator::runImpl(unsigned long sampleCount)
{
    if (!m_input || !m_output) return;

    int ii = 0;
    int oi = 0;

    while (ii < sampleCount) {

        m_output[oi++] = m_outacc[m_read++] / 1.5f;

        if (m_fill == m_fftsize) {

            processFrame();

            for (int j = m_increment; j < m_fftsize; ++j) {
                m_buffer[j - m_increment] = m_buffer[j];
            }

            for (int j = m_increment; j < m_fftsize*2; ++j) {
                m_outacc[j - m_increment] = m_outacc[j];
            }

            for (int j = m_fftsize*2 - m_increment; j < m_fftsize*2; ++j) {
                m_outacc[j] = 0.f;
            }

            m_fill -= m_increment;
            m_read -= m_increment;
        }

        m_buffer[m_fill++] = m_input[ii++];
    }
}

void
Devuvuzelator::processFrame()
{
    double *frame = (double *)alloca(m_fftsize * sizeof(double));
    int ix = m_fftsize/2;
    for (int i = 0; i < m_fftsize; ++i) {
        frame[ix++] = m_buffer[i] * m_window[i];
        if (ix == m_fftsize) ix = 0;
    }

    fft(m_fftsize, false, frame, 0, m_real, m_imag);

    processSpectralFrame();

    for (int i = 0; i < m_fftsize/2-1; ++i) {
        m_real[m_fftsize-i] =  m_real[i+1];
        m_imag[m_fftsize-i] = -m_imag[i+1];
    }

    double *spare = (double *)alloca(m_fftsize * sizeof(double));
    fft(m_fftsize, true, m_real, m_imag, frame, spare);

    ix = m_fftsize/2;
    for (int i = 0; i < m_fftsize; ++i) {
        m_outacc[m_fftsize + i] += frame[ix++] * m_window[i];
        if (ix == m_fftsize) ix = 0;
    }
}

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 = 0; h < harmonics; ++h) {

        double lowfreq = lowfun * (h+1);
        double highfreq = highfun * (h+1);

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

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

// FFT implementation by Don Cross, public domain.
// This version scales the forward transform.

void Devuvuzelator::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;
	}
    }

    static unsigned int tableSize = 0;
    static int *table = 0;

    if (tableSize != n) {

	delete[] table;

	table = new int[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;
	}

	tableSize = n;
    }

    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;
    }

    if (!inverse) {

	double denom = (double)n;

	for (i = 0; i < n; i++) {
	    ro[i] /= denom;
	    io[i] /= denom;
	}
    }
}

AudioEffect *createEffectInstance(audioMasterCallback audioMaster)
{
    return new Devuvuzelator(audioMaster);
}