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add a upsampler

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This commit is contained in:
KubaPro010
2025-03-08 21:19:15 +01:00
parent 2c97f9c8f9
commit 568f8194ee
3 changed files with 47 additions and 5 deletions
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22
lib/filters.c
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@@ -31,6 +31,28 @@ float apply_biquad(BiquadFilter* filter, float input) {
return out;
}
void init_upsampler(Upsampler* up, int ratio, float sample_rate) {
up->i = 0;
up->ratio = ratio;
init_lpf(&up->lpf, sample_rate*ratio, 0.70710678f, sample_rate);
}
float upsample(Upsampler* up, float sample) {
float output = 0.0f;
if (up->i == 0) {
output = sample * up->ratio;
} else {
output = 0.0f;
}
output = apply_biquad(&up->lpf, output);
up->i = (up->i + 1) % up->ratio;
return output;
}
float hard_clip(float sample, float threshold) {
if (sample > threshold) {
return threshold; // Clip to the upper threshold

9
lib/filters.h
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@@ -23,6 +23,15 @@ typedef struct {
void init_lpf(BiquadFilter* filter, float cutoffFreq, float qFactor, float sampleRate);
float apply_biquad(BiquadFilter* filter, float input);
typedef struct
{
int i;
int ratio;
BiquadFilter lpf;
} Upsampler;
void init_upsampler(Upsampler* up, int ratio, float sample_rate);
float upsample(Upsampler *up, float sample);
float hard_clip(float sample, float threshold);
float voltage_db_to_voltage(float db);
float power_db_to_voltage(float db);