radio95/fm95
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fucking shit

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KubaPro010
2026-02-15 18:22:48 +01:00
parent 73396a6cba
commit 6330cbe3a3
2 changed files with 40 additions and 43 deletions
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79
filter/bs412.c
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@@ -13,83 +13,80 @@ inline float deviation_to_dbr(float deviation) {
return 10*log10f((deviation*deviation)/SQRT19000);
}
void init_bs412(BS412Compressor* mpx, uint32_t mpx_deviation, float target_power, float attack, float release, uint32_t sample_rate) {
mpx->mpx_deviation = mpx_deviation;
mpx->avg_power = 0.0f;
mpx->alpha = 1.0f / (BS412_TIME * sample_rate);
mpx->sample_rate = sample_rate;
mpx->attack = expf(-1.0f / (attack * sample_rate));
mpx->release = expf(-1.0f / (release * sample_rate));
mpx->target = deviation_to_dbr(19000.0f * pow(10.0, target_power / 10.0)); // target is expected to not be our rms format
mpx->gain = 0.0f;
mpx->can_compress = 0;
mpx->second_counter = 0;
mpx->last_output = 0.0f;
void init_bs412(BS412Compressor* comp, uint32_t mpx_deviation, float target_power, float attack, float release, uint32_t sample_rate) {
comp->mpx_deviation = mpx_deviation;
comp->avg_power = 0.0f;
comp->alpha = 1.0f / (BS412_TIME * sample_rate);
comp->sample_rate = sample_rate;
comp->attack = expf(-1.0f / (attack * sample_rate));
comp->release = expf(-1.0f / (release * sample_rate));
comp->target = deviation_to_dbr(19000.0f * pow(10.0, target_power / 10.0)); // target is expected to not be our rms format
comp->gain = 0.0f;
comp->can_compress = 0;
comp->second_counter = 0;
comp->last_output = 0.0f;
#ifdef BS412_DEBUG
debug_printf("Initialized MPX power measurement with sample rate: %d\n", sample_rate);
#endif
}
float bs412_compress(BS412Compressor* mpx, float audio, float sample_mpx) {
float bs412_compress(BS412Compressor* comp, float audio, float sample_mpx) {
float combined = audio + sample_mpx;
mpx->avg_power += mpx->alpha * ((mpx->last_output * mpx->last_output * mpx->mpx_deviation * mpx->mpx_deviation) - mpx->avg_power);
comp->avg_power += comp->alpha * ((comp->last_output * comp->last_output * comp->mpx_deviation * comp->mpx_deviation) - comp->avg_power);
float avg_deviation = sqrtf(mpx->avg_power);
float avg_deviation = sqrtf(comp->avg_power);
float modulation_power = deviation_to_dbr(avg_deviation);
if(mpx->target <= -100.0f) {
if(comp->target <= -100.0f) {
#ifdef BS412_DEBUG
if(mpx->sample_counter > mpx->sample_rate) {
if(comp->sample_counter > comp->sample_rate) {
debug_printf("MPX power: %.2f dBr (%.1f Hz)\n", modulation_power, avg_deviation);
mpx->sample_counter = 0;
comp->sample_counter = 0;
}
#endif
mpx->sample_counter++;
comp->sample_counter++;
return combined;
}
if(mpx->sample_counter > mpx->sample_rate) {
if(comp->sample_counter > comp->sample_rate) {
#ifdef BS412_DEBUG
debug_printf("MPX power: %.2f dBr with gain %.2fx (%.2f dBr)\n", modulation_power, mpx->gain, deviation_to_dbr(avg_deviation * mpx->gain));
#endif
mpx->sample_counter = 0;
if(mpx->can_compress == 0) mpx->second_counter++;
comp->sample_counter = 0;
if(comp->can_compress == 0) comp->second_counter++;
}
if(mpx->can_compress == 0 && mpx->second_counter > BS412_TIME) {
if(comp->can_compress == 0 && comp->second_counter > BS412_TIME) {
#ifdef BS412_DEBUG
debug_printf("Can compress.\n");
#endif
mpx->gain = powf(10.0f, (mpx->target - modulation_power) / 10.0f);
mpx->can_compress = 1;
comp->gain = powf(10.0f, (comp->target - modulation_power) / 10.0f);
comp->can_compress = 1;
}
if(mpx->can_compress == 0) {
mpx->sample_counter++;
if(comp->can_compress == 0) {
comp->sample_counter++;
return combined;
}
float target_gain = powf(10.0f, (mpx->target - modulation_power) / 10.0f);
if (modulation_power > mpx->target) {
mpx->gain = mpx->attack * mpx->gain + (1.0f - mpx->attack) * target_gain;
} else {
mpx->gain = mpx->release * mpx->gain + (1.0f - mpx->release) * target_gain;
}
float target_gain = powf(10.0f, (comp->target - modulation_power) / 10.0f);
if (modulation_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;
mpx->gain = fmaxf(0.0f, fminf(2.0f, mpx->gain));
comp->gain = fmaxf(0.0f, fminf(2.0f, comp->gain));
float output_sample = (audio * mpx->gain) + mpx;
if(deviation_to_dbr(avg_deviation * mpx->gain) > mpx->target && deviation_to_dbr(avg_deviation) < mpx->target) {
float output_sample = (audio * comp->gain) + comp;
if(deviation_to_dbr(avg_deviation * comp->gain) > comp->target && deviation_to_dbr(avg_deviation) < comp->target) {
// Gain is too much, reduce
float overshoot_dbr = deviation_to_dbr(avg_deviation * mpx->gain) - mpx->target;
float overshoot_dbr = deviation_to_dbr(avg_deviation * comp->gain) - comp->target;
float reduction_factor = powf(10.0f, -overshoot_dbr / 10.0f);
mpx->gain *= reduction_factor;
mpx->gain = fmaxf(0.0f, fminf(2.0f, mpx->gain));
comp->gain *= reduction_factor;
comp->gain = fmaxf(0.0f, fminf(2.0f, comp->gain));
}
mpx->sample_counter++;
comp->sample_counter++;
mpx->last_output = output_sample;
comp->last_output = output_sample;
return output_sample;
}

4
filter/bs412.h
View File

@@ -30,5 +30,5 @@ typedef struct
// float dbr_to_deviation(float dbr);
float deviation_to_dbr(float deviation);
void init_bs412(BS412Compressor *mpx, uint32_t mpx_deviation, float target_power, float attack, float release, uint32_t sample_rate);
float bs412_compress(BS412Compressor *mpx, float audio, float sample_mpx);
void init_bs412(BS412Compressor *comp, uint32_t mpx_deviation, float target_power, float attack, float release, uint32_t sample_rate);
float bs412_compress(BS412Compressor *comp, float audio, float sample_mpx);