radio95/fm95
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fixes

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This commit is contained in:
kuba
2026-04-28 19:56:13 +02:00
parent 17d84fb8a8
commit 0782a64710
2 changed files with 21 additions and 29 deletions
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filter/bs412.c
+21 -27
View File
@@ -1,19 +1,19 @@
#include "bs412.h"
#define BS412_TIME 60
#define ENABLE_TIME 50
#define CLAMP(x, lo, hi) (((x) < (lo)) ? (lo) : ((x) > (hi) ? (hi) : (x)))
#define SQRT19000 180499999.99999997f // (19000 / sqrt(2)) * 19000 / sqrt(2)
// inline float dbr_to_deviation(float dbr) {
// return 19000.0f * sqrtf(pow(10.0, dbr / 10.0));
// }
inline float deviation_to_dbr(float deviation) {
if (deviation < 1e-6f) return -100.0f;
return 10*log10f((deviation*deviation)/SQRT19000);
inline float dbr_to_deviation(float dbr) {
return 19000.0f * sqrtf(pow(10.0, dbr / 10.0));
}
// #define SQRT19000 180499999.99999997f // (19000 / sqrt(2)) * 19000 / sqrt(2)
// inline float deviation_to_dbr(float deviation) {
// if (deviation < 1e-6f) return -100.0f;
// return 10*log10f((deviation*deviation)/SQRT19000);
// }
void init_bs412(BS412Compressor* comp, uint32_t mpx_deviation, float target_power, float attack, float release, float max_gain, uint32_t sample_rate) {
comp->mpx_deviation = mpx_deviation;
comp->avg_power = 0.0f;
@@ -21,7 +21,7 @@ void init_bs412(BS412Compressor* comp, uint32_t mpx_deviation, float target_powe
comp->sample_rate = sample_rate;
comp->attack = expf(-1.0f / (attack * sample_rate));
comp->release = expf(-1.0f / (release * sample_rate));
comp->target = target_power; // target is expected to not be our rms format
comp->target = dbr_to_deviation(target_power) * dbr_to_deviation(target_power);
comp->gain = 1.0f;
comp->can_compress = 0;
comp->second_counter = 0;
@@ -37,41 +37,35 @@ float bs412_compress(BS412Compressor* comp, float audio, float sample_mpx) {
comp->avg_power += comp->alpha * ((output_sample * output_sample * comp->mpx_deviation * comp->mpx_deviation) - comp->avg_power);
if(comp->sample_counter % 8 == 0) {
comp->avg_deviation = sqrtf(comp->avg_power);
comp->modulation_power = deviation_to_dbr(comp->avg_deviation);
}
if(comp->sample_counter > comp->sample_rate) {
comp->sample_counter = 0;
if(comp->can_compress == 0) comp->second_counter++;
}
if(comp->can_compress == 0 && comp->second_counter > BS412_TIME) {
if(comp->can_compress == 0 && comp->second_counter > ENABLE_TIME) {
#ifdef BS412_DEBUG
debug_printf("Can compress.\n");
#endif
comp->can_compress = 1;
comp->second_counter = 0;
} else {
comp->sample_counter++;
return combined;
}
float target_gain = expf((comp->target - comp->modulation_power) * 0.2302585093f); // 1/10 * ln(10)
if (comp->modulation_power > comp->target) comp->gain = comp->attack * comp->gain + (1.0f - comp->attack) * target_gain;
float safe_power = fmaxf(comp->avg_power, 1e-12f);
float target_gain = sqrtf(comp->target / safe_power);
if (comp->avg_power > comp->target) comp->gain = comp->attack * comp->gain + (1.0f - comp->attack) * target_gain;
else comp->gain = comp->release * comp->gain + (1.0f - comp->release) * target_gain;
comp->gain = CLAMP(comp->gain, 0.0f, comp->max_gain);
float dev_after_gain = deviation_to_dbr(comp->avg_deviation * comp->gain);
if(dev_after_gain > comp->target && comp->modulation_power < comp->target) {
// Gain is too much, reduce
float reduction_factor = expf((comp->target - dev_after_gain) * 0.2302585093f);
comp->gain = CLAMP(comp->gain * reduction_factor, 0.01f, comp->max_gain);
float power_after_gain = comp->avg_power * comp->gain * comp->gain;
if(power_after_gain > comp->target && comp->avg_power < comp->target) {
float reduction = sqrtf(comp->target / power_after_gain);
comp->gain = CLAMP(comp->gain * reduction, 0.01f, comp->max_gain);
}
comp->sample_counter++;
return output_sample;
if(comp->can_compress) return output_sample;
return combined;
}
filter/bs412.h
-2
View File
@@ -26,8 +26,6 @@ typedef struct
uint8_t can_compress : 1;
uint8_t second_counter;
float last_output;
float avg_deviation;
float modulation_power;
} BS412Compressor;
// float dbr_to_deviation(float dbr);