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fix preemphasis

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This commit is contained in:
KubaPro010
2024-12-30 16:54:25 +01:00
parent b3e41197bc
commit 294a7fe35b
1 changed files with 4 additions and 2 deletions
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6
stereo_coder.c
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@@ -70,14 +70,16 @@ float get_next_sample(Oscillator *osc) {
#ifdef PREEMPHASIS #ifdef PREEMPHASIS
typedef struct { typedef struct {
float prev_sample; float prev_sample;
float alpha;
} PreEmphasis; } PreEmphasis;
void init_pre_emphasis(PreEmphasis *pe) { void init_pre_emphasis(PreEmphasis *pe) {
pe->prev_sample = 0.0f; pe->prev_sample = 0.0f;
pe->alpha = exp(-1 / (PREEMPHASIS_TAU*SAMPLE_RATE));
} }
float apply_pre_emphasis(PreEmphasis *pe, float sample) { float apply_pre_emphasis(PreEmphasis *pe, float sample) {
float output = sample - pe->prev_sample * (1.0f - (1 - exp(-1.0 / (SAMPLE_RATE * PREEMPHASIS_TAU)))); float output = sample - pe->alpha * pe->prev_sample;
pe->prev_sample = sample; pe->prev_sample = output;
return output; return output;
} }
#endif #endif