Rack/plugins/community/repos/squinkylabs-plug1/test/Analyzer.cpp

#include <assert.h>

#include "asserts.h"
#include "Analyzer.h"
#include "AudioMath.h"
#include "FFT.h"
#include "FFTData.h"
#include "SinOscillator.h"
#include "AudioMath.h"


int Analyzer::getMax(const FFTDataCpx& data)
{
    return getMaxExcluding(data, std::set<int>());
}

int Analyzer::getMaxExcluding(const FFTDataCpx& data, int exclusion)
{
    std::set<int> exclusions;
    exclusions.insert(exclusion);
    return getMaxExcluding(data, exclusions);
}

int Analyzer::getMaxExcluding(const FFTDataCpx& data, std::set<int> exclusions)
{
    int maxBin = -1;
    float maxMag = 0;
    for (int i = 0; i < data.size(); ++i) {
        if (exclusions.find(i) == exclusions.end()) {
            const float mag = std::abs(data.get(i));
            if (mag > maxMag) {
                maxMag = mag;
                maxBin = i;
            }
        }
    }
    return maxBin;
}

float Analyzer::getSlope(const FFTDataCpx& response, float fTest, float sampleRate)
{
    const int bin1 = FFT::freqToBin(fTest, sampleRate, response.size());
    const int bin2 = bin1 * 4;                // two octaves
    assert(bin2 < response.size());
    const float mag1 = response.getAbs(bin1);
    const float mag2 = response.getAbs(bin2);
    return float(AudioMath::db(mag2) - AudioMath::db(mag1)) / 2;
}

std::tuple<int, int, int> Analyzer::getMaxAndShoulders(const FFTDataCpx& data, float atten)
{
    assert(atten < 0);
    int maxBin = getMax(data);
    int iMax = data.size() / 2;

    assert(maxBin >= 0);
    const double dbShoulder = atten + AudioMath::db(std::abs(data.get(maxBin)));

    int i;
    int iShoulderLow = -1;
    int iShoulderHigh = -1;
    bool done;
    for (done = false, i = maxBin; !done; ) {
        const double db = AudioMath::db(std::abs(data.get(i)));
        if (i >= iMax) {
            done = true;
        } else if (db <= dbShoulder) {
            iShoulderHigh = i;
            done = true;
        } else {
            i++;
        }
    }
    for (done = false, i = maxBin; !done; ) {
        const double db = AudioMath::db(std::abs(data.get(i)));
        if (db <= dbShoulder) {
            iShoulderLow = i;
            done = true;
        } else if (i <= 0) {
            done = true;
        } else {
            i--;
        }
    }
   // printf("out of loop, imax=%d, shoulders=%d,%d\n", maxBin, iShoulderLow, iShoulderHigh);

    return std::make_tuple(iShoulderLow, maxBin, iShoulderHigh);
}

std::tuple<double, double, double> Analyzer::getMaxAndShouldersFreq(const FFTDataCpx& data, float atten, float sampleRate)
{
    auto stats = getMaxAndShoulders(data, atten);
    return  std::make_tuple(FFT::bin2Freq(std::get<0>(stats), sampleRate, data.size()),
        FFT::bin2Freq(std::get<1>(stats), sampleRate, data.size()),
        FFT::bin2Freq(std::get<2>(stats), sampleRate, data.size())
    );
}


// TODO: pass in cutoff
std::vector<Analyzer::FPoint> Analyzer::getFeatures(const FFTDataCpx& data, float sensitivityDb, float sampleRate, float dbMinCutoff)
{
   // TODO: pass this in
  //  const float dbMinCutoff = -100;
    assert(sensitivityDb > 0);
    std::vector<FPoint> ret;
    float lastDb = 10000000000;
    // only look at the below nyquist stuff
    for (int i = 0; i < data.size() / 2; ++i) {
        const float db = (float) AudioMath::db(std::abs(data.get(i)));
        if ((std::abs(db - lastDb) >= sensitivityDb) && (db > dbMinCutoff)) {
            double freq = FFT::bin2Freq(i, sampleRate, data.size());
            FPoint p(float(freq), db);
           // printf("feature at bin %d, db=%f raw val=%f\n", i, db, std::abs(data.get(i)));
            ret.push_back(p);
            lastDb = db;
        }
    }
    return ret;
}


std::vector<Analyzer::FPoint> Analyzer::getPeaks(const FFTDataCpx& data, float sampleRate, float minDb)
{
    std::vector<FPoint> ret;

    // only look at the below nyquist stuff
    for (int i = 0; i < data.size() / 2; ++i) {
        const double mag = std::abs(data.get(i));
        const double db = AudioMath::db(mag);
        bool isPeak = false;
        if (i < 2 || i >(data.size() / 2) - 2) {
            isPeak = true;
        } else {

            const double magBelow = std::abs(data.get(i - 1));
            const double magAbove = std::abs(data.get(i + 1));
            if (mag <= magBelow || mag <= magAbove) {
                isPeak = false;
            } else {

#if 1
                double average = 0;
                for (int j = 0; j < 5; ++j) {
                    average += std::abs(data.get(i + j - 2));
                }
                average -= mag;             // subtract out our contribution
                average /= 4.0;
#if 0
                double a = std::abs(data.get(i - 2));
                double b = std::abs(data.get(i - 1));
                double c = std::abs(data.get(i - 0));
                double d = std::abs(data.get(i + 1));
                double e = std::abs(data.get(i + 2));
#endif
                isPeak = (mag > (average * 2));
#else
                //this way average db
                double average = 0;
                for (int j = 0; j < 5; ++j) {
                    average += AudioMath::db(std::abs(data.get(i + j - 2)));
                }
                isPeak = (db > (average + 3));
#endif
                //if (isPeak) printf("accepted peak at %f db, average was %f\n", db, average);
            }
        }
        if (db < minDb) {
            isPeak = false;
        }

        if (isPeak) {
        //if ((std::abs(db - lastDb) >= sensitivityDb) && (db > dbMinCutoff)) {
            double freq = FFT::bin2Freq(i, sampleRate, data.size());
            FPoint p(float(freq), (float) db);
            // printf("feature at bin %d, db=%f raw val=%f\n", i, db, std::abs(data.get(i)));
            ret.push_back(p);
        }
    }
    return ret;
}

void Analyzer::getAndPrintFeatures(const FFTDataCpx& data, float sensitivityDb, float sampleRate, float dbMinCutoff)
{
    auto features = getFeatures(data, sensitivityDb, sampleRate, dbMinCutoff);
    printf("there are %d features\n", (int) features.size());
    for (int i = 0; i < (int) features.size(); ++i) {
        printf("feature: freq=%.2f, db=%.2f\n", features[i].freq, features[i].gainDb);
    }
}

void Analyzer::getAndPrintPeaks(const FFTDataCpx& data, float sampleRate, float minDb)
{
    auto peaks = getPeaks(data, sampleRate, minDb);
    printf("there are %d peaks\n", (int) peaks.size());
    for (int i = 0; i < (int) peaks.size(); ++i) {
        printf("peak: freq=%f, db=%f\n", peaks[i].freq, peaks[i].gainDb);
    }
}


void Analyzer::getAndPrintFreqOfInterest(const FFTDataCpx& data, float sampleRate, const std::vector<double>& freqOfInterest)
{
    for (double freq : freqOfInterest) {
        int bin = FFT::freqToBin((float) freq, sampleRate, data.size());
        if (bin > 2 && bin < data.size() - 2) {

            ;
            double a = AudioMath::db(std::abs(data.get(bin - 2)));
            double b = AudioMath::db(std::abs(data.get(bin - 1)));
            double c = AudioMath::db(std::abs(data.get(bin)));
            double d = AudioMath::db(std::abs(data.get(bin + 1)));
            double e = AudioMath::db(std::abs(data.get(bin + 2)));

            double db = std::max(e, std::max(
                std::max(a, b),
                std::max(c, d)));

            printf("freq=%.2f db=%f  range:%.2f,%.2f,%.2f,%.2f,%.2f\n", freq, db,
                a, b, c, d, e
            );
        }
    }

#if 0
    for (int i = 0; i < data.size() / 2; ++i) {
        double freq = FFT::bin2Freq(i, sampleRate, data.size());
    }
#endif

}

void Analyzer::getFreqResponse(FFTDataCpx& out, std::function<float(float)> func)
{
    /**
    * testSignal is the time domain sweep
    * testOutput if the time domain output of "func"
    * testSpecrum is the FFT of testSignal
    * spectrum is the FFT of testOutput

    */
    // First set up a test signal 
    const int numSamples = out.size();
    //  std::vector<float> testSignal(numSamples);
    FFTDataReal testSignal(numSamples);
    generateSweep(44100, testSignal.data(), numSamples, 20, 20000);

    // Run the test signal though func, capture output in fft real
    FFTDataReal testOutput(numSamples);
    for (int i = 0; i < out.size(); ++i) {
        const float y = func(testSignal.get(i));
        testOutput.set(i, y);
    }

    // then take the inverse fft
    FFTDataCpx spectrum(numSamples);
    FFT::forward(&spectrum, testOutput);


    // take the forward FFT of the test signal
    FFTDataCpx testSpectrum(numSamples);
    FFT::forward(&testSpectrum, testSignal);

    for (int i = 0; i < numSamples; ++i) {
        const cpx x = (std::abs(testSpectrum.get(i)) == 0) ? 0 :
            spectrum.get(i) / testSpectrum.get(i);
        out.set(i, x);
    }

#if 0
    for (int i = 0; i < numSamples; ++i) {
        printf("%d, sig=%f out=%f mag(sig)=%f mag(out)=%f rsp=%f\n",
            i, testSignal.get(i), testOutput.get(i),
            std::abs(testSpectrum.get(i)),
            std::abs(spectrum.get(i)),
            std::abs(out.get(i))
        );
    }
#endif
}


double Analyzer::hamming(int iSample, int totalSamples)
{
    const double a0 = .53836;
    double theta = AudioMath::Pi * 2.0 * double(iSample) / double(totalSamples - 1);
    return a0 - (1.0 - a0) * std::cos(theta);
}

void Analyzer::getSpectrum(FFTDataCpx& out, bool useWindow, std::function<float()> func)
{

    const int numSamples = out.size();

    // Run the test signal though func, capture output in fft real
    FFTDataReal testOutput(numSamples);
    for (int i = 0; i < out.size(); ++i) {
        const float w = useWindow ? (float) hamming(i, out.size()) : 1;
        const float y = float(func() * w);
        testOutput.set(i, y);
    }

    FFT::forward(&out, testOutput);

#if 0
    for (int i = 0; i < numSamples; ++i) {
        printf("%d, sig=%f out=%f mag(sig)=%f mag(out)=%f rsp=%f\n",
            i, testSignal.get(i), testOutput.get(i),
            std::abs(testSpectrum.get(i)),
            std::abs(spectrum.get(i)),
            std::abs(out.get(i))
        );
    }
#endif
}

void Analyzer::generateSweep(float sampleRate, float* out, int numSamples, float minFreq, float maxFreq)
{
    assert(maxFreq > minFreq);
    const double minLog = std::log2(minFreq);
    const double maxLog = std::log2(maxFreq);
    const double delta = (maxLog - minLog) / numSamples;

    SinOscillatorParams<double> params;
    SinOscillatorState<double> state;

    double fLog = minLog;
    for (int i = 0; i < numSamples; ++i, fLog += delta) {
        const double freq = std::pow(2, fLog);
        assert(freq < (sampleRate / 2));

        SinOscillator<double, false>::setFrequency(params, freq / sampleRate);
        double val = SinOscillator<double, false>::run(state, params);

       // ::printf("out[%d] = %f f=%f\n", i, val, freq);
        out[i] = (float) val;
    }
}

double Analyzer::makeEvenPeriod(double desiredFreq, double sampleRate, int numSamples)
{
    assert(desiredFreq <= (sampleRate / 2.0));
    assert(numSamples > 2);
    double desiredPeriodSamples = sampleRate / desiredFreq;
    double periodsPerFrame = numSamples / desiredPeriodSamples;


     //printf("desiredFreq = %f, desired period/ samp = %f, periods per frame = %f\n", desiredFreq, desiredPeriodSamples, periodsPerFrame);


    double evenPeriodsPerFrame = std::floor(periodsPerFrame);

    double period = (double) numSamples / evenPeriodsPerFrame;
    //printf("period = %f\n", period);
    double freq = sampleRate / period;
    //printf("freq = %f\n", freq);
    assert(freq > .0001);       // don't want zero
    return (freq);
}

void Analyzer::assertSingleFreq(const FFTDataCpx& spectrum, float expectedFreq, float sampleRate)
{
    assert(expectedFreq < (sampleRate / 2));
    int maxBin = Analyzer::getMax(spectrum);
    double maxFreq = FFT::bin2Freq(maxBin, sampleRate, spectrum.size());

    int nextMaxBin = Analyzer::getMaxExcluding(spectrum, maxBin);
    float maxPower = std::abs(spectrum.get(maxBin));
    float nextMaxPower = std::abs(spectrum.get(nextMaxBin));

    double spuriousDb = AudioMath::db(nextMaxPower / maxPower);

    assertClose(maxFreq, expectedFreq, 1);
    assertLE(spuriousDb, 70);
}