mirror of
https://github.com/Boof2015/astra-mobile.git
synced 2026-08-12 13:20:54 +02:00
Boof2015
92 lines
2.7 KiB
C++
92 lines
2.7 KiB
C++
#pragma once
|
|
#define _USE_MATH_DEFINES
|
|
#include <cmath>
|
|
#ifndef M_PI
|
|
#define M_PI 3.14159265358979323846
|
|
#endif
|
|
|
|
#include <vector>
|
|
#include <complex>
|
|
#include <algorithm>
|
|
|
|
namespace DSP {
|
|
|
|
// Simple FFT implementation (Cooley-Tukey radix-2)
|
|
class FFT {
|
|
public:
|
|
explicit FFT(size_t size);
|
|
void forward(const float* input, float* magnitudes);
|
|
void forward(const float* input, std::complex<float>* output);
|
|
size_t getSize() const { return size_; }
|
|
|
|
private:
|
|
size_t size_;
|
|
std::vector<std::complex<float>> twiddles_;
|
|
std::vector<std::complex<float>> buffer_; // Reuse buffer to avoid allocations
|
|
std::vector<std::complex<float>> scratch_; // Scratch buffer if needed
|
|
void bitReverse(std::complex<float>* data);
|
|
};
|
|
|
|
// Biquad filter for lowpass/bandpass
|
|
class BiquadFilter {
|
|
public:
|
|
BiquadFilter();
|
|
void setLowpass(float frequency, float sampleRate, float Q = 0.707f);
|
|
void setBandpass(float frequency, float sampleRate, float Q = 2.0f);
|
|
void setHighShelf(float frequency, float sampleRate, float gainDB, float Q = 0.707f);
|
|
float process(float input);
|
|
void reset();
|
|
|
|
// Process entire buffer (bidirectional for zero phase)
|
|
void processBuffer(const float* input, float* output, size_t length, bool bidirectional = true);
|
|
|
|
private:
|
|
float b0_, b1_, b2_;
|
|
float a1_, a2_;
|
|
float x1_, x2_;
|
|
float y1_, y2_;
|
|
};
|
|
|
|
// Linear-phase FIR filter for stable trigger detection
|
|
// Uses Kaiser-windowed bandpass design for consistent zero crossings
|
|
class FIRFilter {
|
|
public:
|
|
FIRFilter();
|
|
|
|
// Design Kaiser-windowed bandpass filter centered on frequency
|
|
void designBandpass(float centerFreq, float bandwidth, float sampleRate, float sidelobeAtten = 60.0f);
|
|
|
|
// Process single sample
|
|
float process(float input);
|
|
|
|
// Get filter delay (for phase compensation)
|
|
size_t getDelay() const { return order_ / 2; }
|
|
|
|
// Reset filter state
|
|
void reset();
|
|
|
|
private:
|
|
std::vector<float> coeffs_;
|
|
std::vector<float> delay_;
|
|
size_t idx_;
|
|
size_t order_;
|
|
|
|
// Kaiser window helpers
|
|
static std::vector<float> kaiserWindow(size_t length, float beta);
|
|
static double besselI0(double x);
|
|
};
|
|
|
|
// Pitch detection using autocorrelation
|
|
float detectPitch(const float* data, size_t length, float sampleRate, float minFreq = 40.0f, float maxFreq = 2000.0f);
|
|
|
|
// FFT-based pitch detection (more stable than autocorrelation)
|
|
float detectPitchFFT(const float* data, size_t length, float sampleRate, float minFreq = 40.0f, float maxFreq = 2000.0f);
|
|
|
|
// Find zero-crossing trigger point with hysteresis/hold-off (sub-sample precision)
|
|
float findTriggerPoint(const float* data, size_t length, int searchStart, int searchEnd);
|
|
|
|
// Calculate RMS
|
|
float calculateRMS(const float* data, size_t length);
|
|
|
|
} // namespace DSP
|