transient.h

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#pragma once
 
#include "fl/audio/audio_detector.h"
#include "fl/math/filter/filter.h"
#include "fl/stl/function.h"
#include "fl/stl/vector.h"
#include "fl/stl/deque.h"
#include "fl/stl/noexcept.h"
 
namespace fl {
namespace audio {
namespace detector {

class Transient : public Detector {
public:
    Transient() FL_NO_EXCEPT;
    ~Transient() FL_NO_EXCEPT override;
 
    void update(shared_ptr<Context> context) FL_NO_EXCEPT override;
    void fireCallbacks() FL_NO_EXCEPT override;
    bool needsFFT() const FL_NO_EXCEPT override { return true; }
    const char* getName() const FL_NO_EXCEPT override { return "Transient"; }
    void reset() FL_NO_EXCEPT override;
 
    // Callbacks (multiple listeners supported)
    function_list<void()> onTransient;
    function_list<void(float strength)> onTransientWithStrength;
    function_list<void(float strength)> onAttack;
 
    // State access
    bool isTransient() const FL_NO_EXCEPT { return mTransientDetected; }
    float getStrength() const FL_NO_EXCEPT { return mStrength; }
    float getAttackTime() const FL_NO_EXCEPT { return mAttackTime; }
 
    // Configuration
    void setThreshold(float threshold) FL_NO_EXCEPT { mThreshold = threshold; }
    void setSensitivity(float sensitivity) FL_NO_EXCEPT { mSensitivity = sensitivity; }
    void setMinInterval(u32 intervalMs) FL_NO_EXCEPT { mMinIntervalMs = intervalMs; }
 
private:
    bool mTransientDetected;
    float mStrength;
    float mThreshold;
    float mSensitivity;
    u32 mMinIntervalMs;
    u32 mLastTransientTime;
 
    // Energy tracking
    float mPreviousEnergy;
    float mCurrentEnergy;
    float mAttackTime;  // Time in ms for attack phase
 
    // High-frequency emphasis for transient detection
    vector<float> mPreviousHighFreq;
    deque<float> mEnergyHistory;
    static constexpr size ENERGY_HISTORY_SIZE = 5;
 
    // Adaptive outlier rejection for energy before history
    HampelFilter<float, 7> mEnergyOutlierFilter{2.5f};
 
    shared_ptr<const fft::Bins> mRetainedFFT;
 
    float calculateHighFreqEnergy(const fft::Bins& fft) FL_NO_EXCEPT;
    float calculateEnergyFlux(float currentEnergy) FL_NO_EXCEPT;
    bool detectTransient(float flux, u32 timestamp) FL_NO_EXCEPT;
    void updateAttackTime(float flux) FL_NO_EXCEPT;
};
 
} // namespace detector
} // namespace audio
} // namespace fl