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Code Issues Activity

bs412 gating and also fix it

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This commit is contained in:
kuba
2026-05-04 13:28:30 +02:00
parent fafc201fb4
commit 6f929f0c18
3 changed files with 51 additions and 47 deletions
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filter/bs412.c
+30 -24
View File
@@ -1,43 +1,54 @@
#include "bs412.h"
#define BS412_TIME 60
#define ENABLE_TIME 50
#define ENABLE_TIME 45
#define CLAMP(x, lo, hi) (((x) < (lo)) ? (lo) : ((x) > (hi) ? (hi) : (x)))
inline float dbr_to_deviation(float dbr) {
return 19000.0f * sqrtf(pow(10.0, dbr / 10.0));
}
#define REF_POWER (19000.0f * 19000.0f) // 361,000,000
inline float power_to_dbr(float power) {
inline float power_to_dbr(float power, float ref) {
if (power < 1e-12f) return -100.0f;
return 10*log10f(power / REF_POWER);
return 10*log10f(power / ref);
}
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;
void init_bs412(BS412Compressor* comp, uint32_t mpx_deviation, float target_power, float attack, float release, float max_gain, float gate, uint32_t sample_rate) {
comp->reference = (19000.0f / mpx_deviation) * (19000.0f / mpx_deviation); // 0 dbr is a signal which generates a deviation of 19 khz
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 = dbr_to_deviation(target_power) * dbr_to_deviation(target_power);
comp->target = comp->reference * powf(10.0f, target_power / 10.0f);;
comp->gain = 1.0f;
comp->can_compress = 0;
comp->second_counter = 0;
comp->max_gain = max_gain;
comp->gate_threshold = comp->reference * powf(10.0f, gate / 10.0f);
comp->init = true;
#ifdef BS412_DEBUG
debug_printf("Initialized MPX power measurement with sample rate: %d\n", sample_rate);
#endif
}
void reinit_bs412(BS412Compressor* comp, uint32_t mpx_deviation, float target_power, float attack, float release, float max_gain, float gate) {
comp->reference = (19000.0f / mpx_deviation) * (19000.0f / mpx_deviation); // 0 dbr is a signal which generates a deviation of 19 khz
comp->target = comp->reference * powf(10.0f, target_power / 10.0f);;
comp->gate_threshold = comp->reference * powf(10.0f, gate / 10.0f);
comp->attack = expf(-1.0f / (attack * sample_rate));
comp->release = expf(-1.0f / (release * sample_rate));
comp->max_gain = max_gain;
}
float bs412_compress(BS412Compressor* comp, float audio, float sample_mpx, float* mpx_power) {
float combined = audio + sample_mpx;
float output_sample = (audio * comp->gain) + sample_mpx;
comp->avg_power += comp->alpha * ((output_sample * output_sample * comp->mpx_deviation * comp->mpx_deviation) - comp->avg_power);
float inst_power = output_sample * output_sample;
float audio_power = (audio * comp->gain) * (audio * comp->gain);
if(comp->sample_counter > comp->sample_rate) {
float w = (audio_power - comp->gate_threshold) / comp->gate_threshold;
w = CLAMP(w, 0.0f, 1.0f);
comp->avg_power += comp->alpha * w * (inst_power - comp->avg_power);
if(comp->sample_counter >= comp->sample_rate) {
comp->sample_counter = 0;
if(comp->can_compress == 0) comp->second_counter++;
}
@@ -52,21 +63,16 @@ float bs412_compress(BS412Compressor* comp, float audio, float sample_mpx, float
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;
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 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->gain = CLAMP(comp->gain, 0.01f, comp->max_gain);
comp->sample_counter++;
if(mpx_power != NULL) *mpx_power = power_to_dbr(comp->avg_power);
if(mpx_power != NULL) *mpx_power = power_to_dbr(comp->avg_power, comp->reference);
if(comp->can_compress) return output_sample;
return combined;
filter/bs412.h
+6 -4
View File
@@ -11,9 +11,8 @@
#include "../lib/debug.h"
#endif
typedef struct
{
uint32_t mpx_deviation;
typedef struct {
float reference;
uint32_t sample_rate;
uint32_t sample_counter;
float target;
@@ -26,7 +25,10 @@ typedef struct
uint8_t can_compress : 1;
uint8_t second_counter;
float last_output;
float gate_threshold;
bool init;
} BS412Compressor;
void init_bs412(BS412Compressor *comp, uint32_t mpx_deviation, float target_power, float attack, float release, float max_gain, uint32_t sample_rate);
void init_bs412(BS412Compressor *comp, uint32_t mpx_deviation, float target_power, float attack, float release, float max_gain, float gate, uint32_t sample_rate);
void reinit_bs412(BS412Compressor *comp, uint32_t mpx_deviation, float target_power, float attack, float release, float max_gain, float gate);
float bs412_compress(BS412Compressor *comp, float audio, float sample_mpx, float* mpx_power);
src/fm95.c
+15 -19
View File
@@ -66,6 +66,7 @@ typedef struct {
float bs412_attack;
float bs412_release;
float bs412_max;
float bs412_gate;
float lpf_cutoff;
} FM95_Config;
@@ -328,6 +329,7 @@ static int config_handler(void* user, const char* section, const char* name, con
else if(MATCH("fm95", "bs412_attack")) pconfig->bs412_attack = strtof(value, NULL);
else if(MATCH("fm95", "bs412_release")) pconfig->bs412_release = strtof(value, NULL);
else if(MATCH("fm95", "bs412_max")) pconfig->bs412_max = strtof(value, NULL);
else if(MATCH("fm95", "bs412_gate")) pconfig->bs412_gate = strtof(value, NULL);
else if(MATCH("advanced", "lpf_order")) pconfig->lpf_order = atoi(value);
else if(MATCH("advanced", "stereo_ssb")) pconfig->stereo_ssb = atoi(value);
else if(MATCH("advanced", "preemp_unity")) pconfig->preemp_unity_freq = strtof(value, NULL);
@@ -437,25 +439,9 @@ void init_runtime(FM95_Runtime* runtime, const FM95_Config config) {
init_preemphasis(&runtime->preemp_r, (float)config.preemphasis * 1.0e-6f, config.sample_rate, config.preemp_unity_freq);
}
float last_gain = 0.0f;
float last_power = 0.0f;
uint8_t last_compress = 0;
uint8_t last_sample_counter = 0;
uint8_t last_second_counter = 0;
if(runtime->bs412.sample_rate == config.sample_rate) {
last_gain = runtime->bs412.gain;
last_power = runtime->bs412.avg_power;
last_compress = runtime->bs412.can_compress;
last_sample_counter = runtime->bs412.sample_counter;
last_second_counter = runtime->bs412.second_counter;
}
init_bs412(&runtime->bs412, config.mpx_deviation, config.mpx_power, config.bs412_attack, config.bs412_release, config.bs412_max, config.sample_rate);
runtime->bs412.gain = last_gain;
runtime->bs412.avg_power = last_power;
runtime->bs412.can_compress = last_compress;
runtime->bs412.sample_counter = last_sample_counter;
runtime->bs412.second_counter = last_second_counter;
if(runtime->bs412.init == true && (runtime->bs412.sample_rate == config.sample_rate)) {
reinit_bs412(&runtime->bs412, config.mpx_deviation, config.mpx_power, config.bs412_attack, config.bs412_release, config.bs412_max, config.bs412_gate)
} else init_bs412(&runtime->bs412, config.mpx_deviation, config.mpx_power, config.bs412_attack, config.bs412_release, config.bs412_max, config.bs412_gate, config.sample_rate);
init_stereo_encoder(&runtime->stencode, config.stereo_ssb, 4.0f, &runtime->osc, config.volumes.audio, config.volumes.pilot);
if(config.agc_max != 0.0) {
@@ -529,6 +515,14 @@ static void *handle_client(ipc_client_arg_t *arg) {
data->config->master_volume = val;
reply = 0;
break;
case 105:
// Set BS412 gate
memcpy(&val, buf + 1, sizeof(float));
data->config->bs412_gate = val;
reply = 0;
to_run = 0;
to_reload = 1;
break;
case 0xff:
// Fetch data
send(fd, data->run_result, sizeof(FM95_RunResult), 0);
@@ -585,6 +579,7 @@ int main(int argc, char **argv) {
.bs412_attack = 0.05f,
.bs412_release = 0.025f,
.bs412_max = 2.82f,
.bs412_gate = -20.0f,
.lpf_cutoff = 15000.0f,
};
@@ -642,6 +637,7 @@ int main(int argc, char **argv) {
.runtime = &runtime,
.run_result = &runres
};
ipc_ctx_t ctx;
ipc_ctx_t *pctx = &ctx;
if(create_ipc(pctx, handle_client, "/etc/fm95/ctl.socket", &fmdata) < 0) {