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Code Issues Activity

remove tilt, and add a non-mpx output

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This commit is contained in:
Kuba
2025-10-11 10:22:36 +02:00
parent 53d5d8ec6b
commit 8d00202869
4 changed files with 46 additions and 53 deletions
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22
filter/iir.c
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@@ -13,26 +13,4 @@ inline float apply_preemphasis(ResistorCapacitor *filter, float sample) {
float out = (sample - filter->alpha * filter->prev_sample) * filter->gain;
filter->prev_sample = sample;
return out;
}
void tilt_init(TiltCorrectionFilter* f, float correction_strength, float sr) {
float cutoff = 1000.0f; // fixed split point
// one-pole lowpass setup
float alpha = expf(-2.0f * (float)M_PI * cutoff / sr);
f->a1 = alpha;
f->a0 = 1.0f - alpha;
f->lp = 0.0f;
// simple low/high gains from tilt
float t = (correction_strength < -1.0f) ? -1.0f : (correction_strength > 1.0f ? 1.0f : correction_strength);
f->low_gain = 1.0f - t;
f->high_gain = 1.0f + t;
}
float tilt(TiltCorrectionFilter* f, float in) {
// lowpass
f->lp = f->a0 * in + f->a1 * f->lp;
float hp = in - f->lp;
return f->lp * f->low_gain + hp * f->high_gain;
}

12
filter/iir.h
View File

@@ -11,14 +11,4 @@ typedef struct
} ResistorCapacitor;
void init_preemphasis(ResistorCapacitor *filter, float tau, float sample_rate, float ref_freq);
float apply_preemphasis(ResistorCapacitor *filter, float sample);
typedef struct {
float a0, a1; // lowpass coeffs
float lp; // lowpass state
float low_gain; // gain for low frequencies
float high_gain; // gain for high frequencies
} TiltCorrectionFilter;
void tilt_init(TiltCorrectionFilter* f, float correction_strength, float sr);
float tilt(TiltCorrectionFilter *f, float in);
float apply_preemphasis(ResistorCapacitor *filter, float sample);