DISTRHO-Ports/libs/drowaudio/source/dRowAudio/audio/dRowAudio_PitchDetector.cpp

/*
  ==============================================================================

  This file is part of the dRowAudio JUCE module
  Copyright 2004-13 by dRowAudio.

  ------------------------------------------------------------------------------

  dRowAudio is provided under the terms of The MIT License (MIT):

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
  SOFTWARE.

  ==============================================================================
*/

//==============================================================================
PitchDetector::PitchDetector()
    : detectionMethod       (autoCorrelationFunction),
      sampleRate            (44100.0),
      minFrequency          (50), maxFrequency (1600),
      buffer1               (512), buffer2 (512),
      numSamplesNeededForDetection (int ((sampleRate / minFrequency) * 2)),
      currentBlockBuffer    (numSamplesNeededForDetection),
      inputFifoBuffer       (numSamplesNeededForDetection * 2),
      mostRecentPitch       (0.0)
{
    updateFiltersAndBlockSizes();
}

PitchDetector::~PitchDetector()
{
}

void PitchDetector::processSamples (const float* samples, int numSamples) noexcept
{
    if (inputFifoBuffer.getNumFree() < numSamples)
        inputFifoBuffer.setSizeKeepingExisting (inputFifoBuffer.getSize() * 2);
    
    inputFifoBuffer.writeSamples (samples, numSamples);
    
    while (inputFifoBuffer.getNumAvailable() >= numSamplesNeededForDetection)
    {
        inputFifoBuffer.readSamples (currentBlockBuffer.getData(), currentBlockBuffer.getSize());
        mostRecentPitch = detectPitchForBlock (currentBlockBuffer.getData(), currentBlockBuffer.getSize());
    }
}

//==============================================================================
double PitchDetector::detectPitch (float* samples, int numSamples) noexcept
{
    Array<double> pitches;
    pitches.ensureStorageAllocated (int (numSamples / numSamplesNeededForDetection));
    
    while (numSamples >= numSamplesNeededForDetection)
    {
        double pitch = detectPitchForBlock (samples, numSamplesNeededForDetection);//0.0;
        
        if (pitch > 0.0)
            pitches.add (pitch);
        
        numSamples -= numSamplesNeededForDetection;
        samples += numSamplesNeededForDetection;
    }
    
    if (pitches.size() == 1)
    {
        return pitches[0];
    }
    else if (pitches.size() > 1)
    {
        DefaultElementComparator<double> sorter;
        pitches.sort (sorter);
        
        const double stdDev = findStandardDeviation (pitches.getRawDataPointer(), pitches.size());
        const double medianSample = findMedian (pitches.getRawDataPointer(), pitches.size());
        const double lowerLimit = medianSample - stdDev;
        const double upperLimit = medianSample + stdDev;
        
        Array<double> correctedPitches;
        correctedPitches.ensureStorageAllocated (pitches.size());
        
        for (int i = 0; i < pitches.size(); ++i)
        {
            const double pitch = pitches.getUnchecked (i);
            
            if (pitch >= lowerLimit && pitch <= upperLimit)
                correctedPitches.add (pitch);
        }
        
        const double finalPitch = findMean (correctedPitches.getRawDataPointer(), correctedPitches.size());
        
        return finalPitch;
    }
    
    return 0.0;
}

//==============================================================================
void PitchDetector::setSampleRate (double newSampleRate) noexcept
{
    sampleRate = newSampleRate;
    updateFiltersAndBlockSizes();
}

void PitchDetector::setDetectionMethod (DetectionMethod newMethod)
{
    detectionMethod = newMethod;
}

void PitchDetector::setMinMaxFrequency (float newMinFrequency, float newMaxFrequency) noexcept
{
    minFrequency = newMinFrequency;
    maxFrequency = newMaxFrequency;

    updateFiltersAndBlockSizes();
}

//==============================================================================
Buffer* PitchDetector::getBuffer (int stageIndex)
{
    switch (stageIndex)
    {
        case 1:     return &buffer1;    break;
        case 2:     return &buffer2;    break;
        default:    return nullptr;
    }
    
    return nullptr;
}

//==============================================================================
void PitchDetector::updateFiltersAndBlockSizes()
{
    lowFilter.setCoefficients (IIRCoefficients::makeLowPass (sampleRate, maxFrequency));
    highFilter.setCoefficients (IIRCoefficients::makeHighPass (sampleRate, minFrequency));
    
    numSamplesNeededForDetection = int (sampleRate / minFrequency) * 2;
    
    inputFifoBuffer.setSizeKeepingExisting (numSamplesNeededForDetection * 2);
    currentBlockBuffer.setSize (numSamplesNeededForDetection);
    
    buffer1.setSizeQuick (numSamplesNeededForDetection);
    buffer2.setSizeQuick (numSamplesNeededForDetection);
}

//==============================================================================
double PitchDetector::detectPitchForBlock (float* samples, int numSamples)
{
    switch (detectionMethod)
    {
        case autoCorrelationFunction:   return detectAcfPitchForBlock (samples, numSamples);
        case squareDifferenceFunction:  return detectSdfPitchForBlock (samples, numSamples);
        default:                        return 0.0;
    }
}

double PitchDetector::detectAcfPitchForBlock (float* samples, int numSamples)
{
    const int minSample = int (sampleRate / maxFrequency);
    const int maxSample = int (sampleRate / minFrequency);

    lowFilter.reset();
    highFilter.reset();
    lowFilter.processSamples (samples, numSamples);
    highFilter.processSamples (samples, numSamples);
    
    autocorrelate (samples, numSamples, buffer1.getData());
    normalise (buffer1.getData(), buffer1.getSize());

//    float max = 0.0f;
//    int sampleIndex = 0;
//    for (int i = minSample; i < maxSample; ++i)
//    {
//        const float sample = buffer1.getData()[i];
//        if (sample > max)
//        {
//            max = sample;
//            sampleIndex = i;
//        }
//    }

    float* bufferData = buffer1.getData();
//    const int bufferSize = buffer1.getSize();
    int firstNegativeZero = 0;
    
    // first peak method
    for (int i = 0; i < numSamples - 1; ++i)
    {
        if (bufferData[i] >= 0.0f && bufferData[i + 1] < 0.0f)
        {
            firstNegativeZero = i;
            break;
        }
    }
    
    // apply gain ramp
//    float rampDelta = 1.0f / numSamples;
//    float rampLevel = 1.0f;
//    for (int i = 0; i < numSamples - 1; ++i)
//    {
//        bufferData[i] *= cubeNumber (rampLevel);
//        rampLevel -= rampDelta;
//    }
    
    float max = -1.0f;
    int sampleIndex = 0;
    for (int i = jmax (firstNegativeZero, minSample); i < maxSample; ++i)
    {
        if (bufferData[i] > max)
        {
            max = bufferData[i];
            sampleIndex = i;
        }
    }
    
    
//    buffer2.setSizeQuick (numSamples);
/*    autocorrelate (buffer1.getData(), buffer1.getSize(), buffer2.getData());
    normalise (buffer2.getData(), buffer2.getSize());*/
    //buffer2.quickCopy (buffer1.getData(), buffer1.getSize());
//    differentiate (buffer1.getData(), buffer1.getSize(), buffer2.getData());
//    normalise (buffer2.getData()+2, buffer2.getSize()-2);
//    differentiate (buffer2.getData(), buffer2.getSize(), buffer2.getData());
    
/*    for (int i = minSample + 1; i < maxSample - 1; ++i)
    {
        const float previousSample = buffer2.getData()[i - 1];
        const float sample = buffer2.getData()[i];
        const float nextSample = buffer2.getData()[i + 1];

        if (sample > previousSample
            && sample > nextSample
            && sample > 0.5f)
            sampleIndex = i;
    }*/
    
    //differentiate (buffer2.getData(), buffer2.getSize(), buffer2.getData());
    //normalise (buffer2.getData() + minSample, buffer2.getSize() - minSample);
    
//    float min = 0.0f;
//    int sampleIndex = 0;
//    for (int i = minSample; i < maxSample; ++i)
//    {
//        const float sample = buffer2.getData()[i];
//        if (sample < min)
//        {
//            min = sample;
//            sampleIndex = i;
//        }
//    }


    if (sampleIndex > 0)
        return sampleRate / sampleIndex;
    else
        return 0.0;
}

double PitchDetector::detectSdfPitchForBlock (float* samples, int numSamples)
{
    const int minSample = int (sampleRate / maxFrequency);
    const int maxSample = int (sampleRate / minFrequency);
    
    lowFilter.reset();
    highFilter.reset();
    lowFilter.processSamples (samples, numSamples);
    highFilter.processSamples (samples, numSamples);
    
    sdfAutocorrelate (samples, numSamples, buffer1.getData());
    normalise (buffer1.getData(), buffer1.getSize());
    
    // find first minimum that is below a threshold
    const float threshold = 0.25f;
    const float* sdfData = buffer1.getData();
    float min = 1.0f;
    int index = 0;
    
    for (int i = minSample; i < maxSample; ++i)
    {
        const float prevSample = sdfData[i - 1];
        const float sample =  sdfData[i];
        const float nextSample =  sdfData[i + 1];
        
        if (sample < prevSample
            && sample < nextSample
            && sample < threshold)
        {
            if (sample < min)
            {
                min = sample;
                index = i;
            }
//            return sampleRate / i;
//            break;
        }
    }
    
    if (index != 0)
        return sampleRate / index;
    
    return 0.0;
}