Autocorrelation.h

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/*
  ==============================================================================
 
    SpectralAutocorrelation.h
    Created: 9 Nov 2016 2:48:05pm
    Author:  KrotosMacMini
 
  ==============================================================================
*/
 
#pragma once
 
namespace krotos
{
    class Autocorrelation
    {
      public:
        Autocorrelation();
        Autocorrelation(double newSampleRate, int newBufferSize);
        ~Autocorrelation();
 
        float getPitch(AudioSampleBuffer buffer);
        void initialise(double newSampleRate, int newBufferSize);
 
      private:
        const int MAX_BUFFER_SIZE{1024};
        const double PI{3.14159265358979323846};
        const double TWO_PI{2 * PI};
        const double LOWER_THRESHOLD{0.01};
        const float MAX_FREQ{1000};
        const float MIN_FREQ{20};
        const double DEFAULT_SAMPLE_RATE{44100};
 
        void getAutocorrelation(std::vector<float> data);
        void smoothingFilter(std::vector<float> input, float coefficient);
 
        float getParabolicInterpolation(int estimation);
 
        std::vector<float> audioFrame;
        std::vector<float> autocorrelationBuffer;
        std::vector<float> smoothedAutocorrelation;
        std::vector<float> window;
 
        float pitchEstimate{-1.0f};
        float tauEstimate{-1.0f};
 
        int position{-1};
 
        int bufferSize;
        double sampleRate;
    };
} // namespace krotos