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KubaPro010
2025-12-30 22:06:33 +01:00
parent a5149126c0
commit 2b65557dfe
2 changed files with 13 additions and 18 deletions
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26
filter/bs412.c
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@@ -11,8 +11,8 @@ inline float deviation_to_dbr(float deviation) {
void init_bs412(BS412Compressor* mpx, uint32_t mpx_deviation, float target_power, float attack, float release, float max, uint32_t sample_rate) { void init_bs412(BS412Compressor* mpx, uint32_t mpx_deviation, float target_power, float attack, float release, float max, uint32_t sample_rate) {
mpx->mpx_deviation = mpx_deviation; mpx->mpx_deviation = mpx_deviation;
mpx->average_counter = 0; mpx->avg_power = 0.0f;
mpx->average = 0; mpx->alpha = 1.0f / (60.0f * sample_rate);
mpx->sample_rate = sample_rate; mpx->sample_rate = sample_rate;
mpx->attack = expf(-1.0f / (attack * sample_rate)); mpx->attack = expf(-1.0f / (attack * sample_rate));
mpx->release = expf(-1.0f / (release * sample_rate)); mpx->release = expf(-1.0f / (release * sample_rate));
@@ -34,33 +34,26 @@ static inline float soft_clip_tanh(float sample, float threshold) {
} }
float bs412_compress(BS412Compressor* mpx, float sample) { float bs412_compress(BS412Compressor* mpx, float sample) {
mpx->average += sample * sample * mpx->mpx_deviation * mpx->mpx_deviation; mpx->avg_power += mpx->alpha * ((sample * sample * mpx->mpx_deviation * mpx->mpx_deviation) - mpx->avg_power);
mpx->average_counter++;
float avg_power = mpx->average / mpx->average_counter; float avg_deviation = sqrtf(mpx->avg_power);
float avg_deviation = sqrtf(avg_power) * sqrtf(2);
float modulation_power = deviation_to_dbr(avg_deviation); float modulation_power = deviation_to_dbr(avg_deviation);
if (mpx->average_counter >= mpx->sample_rate * 60) {
#ifdef BS412_DEBUG
debug_printf("Resetting MPX power measurement\n");
#endif
mpx->average = avg_power;
mpx->average_counter = 1;
}
if(mpx->target <= -100.0f) { if(mpx->target <= -100.0f) {
#ifdef BS412_DEBUG #ifdef BS412_DEBUG
if(mpx->average_counter % mpx->sample_rate == 0) { if(mpx->sample_counter > mpx->sample_rate) {
debug_printf("MPX power: %.2f dBr (%.1f Hz)\n", modulation_power, avg_deviation); debug_printf("MPX power: %.2f dBr (%.1f Hz)\n", modulation_power, avg_deviation);
mpx->sample_counter = 0;
} }
#endif #endif
mpx->sample_counter++;
return sample; return sample;
} }
#ifdef BS412_DEBUG #ifdef BS412_DEBUG
if(mpx->average_counter % mpx->sample_rate == 0) { if(mpx->sample_counter > mpx->sample_rate) {
debug_printf("MPX power: %.2f dBr with gain %.2fx (%.2f dBr)\n", modulation_power, mpx->gain, deviation_to_dbr(avg_deviation * mpx->gain)); debug_printf("MPX power: %.2f dBr with gain %.2fx (%.2f dBr)\n", modulation_power, mpx->gain, deviation_to_dbr(avg_deviation * mpx->gain));
mpx->sample_counter = 0;
} }
#endif #endif
@@ -77,5 +70,6 @@ float bs412_compress(BS412Compressor* mpx, float sample) {
float limit_threshold = dbr_to_deviation(mpx->target + 0.1f) / mpx->mpx_deviation; float limit_threshold = dbr_to_deviation(mpx->target + 0.1f) / mpx->mpx_deviation;
output_sample = soft_clip_tanh(output_sample, limit_threshold); output_sample = soft_clip_tanh(output_sample, limit_threshold);
mpx->sample_counter++;
return output_sample; return output_sample;
} }

5
filter/bs412.h
View File

@@ -14,14 +14,15 @@
typedef struct typedef struct
{ {
uint32_t mpx_deviation; uint32_t mpx_deviation;
uint32_t average_counter;
uint32_t sample_rate; uint32_t sample_rate;
uint32_t sample_counter;
float target; float target;
float attack; float attack;
float release; float release;
float max; float max;
float gain; float gain;
double average; double avg_power;
double alpha;
} BS412Compressor; } BS412Compressor;
float dbr_to_deviation(float dbr); float dbr_to_deviation(float dbr);