SlopEnvelopeOnsetdetection.h

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namespace krotos
{
    //==============================================================================
    class EnvelopeFollowerSPD
    {
      public:
        EnvelopeFollowerSPD(float sampleRate);
 
        void setupEnvFol(float attackTimeMs, float releaseTimeMs);
 
        void setAttackMs(float attackTimeMs);
 
        void setReleaseMs(float releaseTimeMs);
 
        std::vector<float> filterVector(std::vector<float> inputMonoVector);
 
        std::vector<float> normaliseEnvelope(std::vector<float> inputMonoVector);
 
      private:
        float m_attackTimeSec;
        float m_releaseTimeSec;
        float m_sampleRate{-1.0f};
 
        // Coeffcients
        float m_gAtt{0.0f};
        float m_gRel{0.0f};
 
        // var holding memory of last sample
        float m_inputSamplePrev{0.0f};
    };
 
    //==============================================================================
    class SlopeGenerator
    {
      public:
        SlopeGenerator() { setNumRegressionPoints(4); };
 
        std::vector<float> createSlopeVectorFromEnvelope(std::vector<float> envelopeVector);
 
        void setNumRegressionPoints(int numRegressionPoints) { m_numRegressionPoints = numRegressionPoints; };
 
      private:
        // sampleRate
        float m_sampleRate;
 
        // number of linear Regression points (4-19)
        int m_numRegressionPoints{};
    };
 
    //==============================================================================
    class OnsetDetector
    {
      public:
        OnsetDetector(float sampleRate);
 
        std::vector<int> calculateOnsetsGlobal(std::vector<float> slopeVector,
                                               std::vector<float> normalisedEnvelopeVector);
 
        void setThresholdPercentage(float thresholdPercentage);
        void setOnsetMiliSeconds(float onsetMiliSeconds);
        void setDecayLengthMiliSeconds(float decayLengthMiliSeconds);
 
      private:
        std::pair<int, int> detectAttackSegment(const std::vector<float>& slopeFrame,
                                                const std::vector<float>& normalisedEnvelopeFrame,
                                                float thresholdValue);
 
        // percentage of max slope to set as slope increase threshold
        float m_threshold{0.0f};
        // forbidden region after attack in ms
        int m_onset{};
        // decay length in ms
        int m_decayLength{};
        // number near 0
        float m_epsilon = 1e-6f;
        // sampleRate
        float m_sampleRate;
 
        bool m_finishFlag{false};
    };
} // namespace krotos