bs412 gating and also fix it

filter/bs412.c

@@ -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) {
+inline float power_to_dbr(float power, float ref) {
-	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) {
     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) {
+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->mpx_deviation = mpx_deviation;
+	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;
+	if (comp->avg_power > comp->target)
-	else comp->gain = comp->release * comp->gain + (1.0f - comp->release) * target_gain;
+		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);
+	comp->gain = CLAMP(comp->gain, 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++;
 
-	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

@@ -11,9 +11,8 @@
 #include "../lib/debug.h"
 #endif
 
-typedef struct
+typedef struct {
-{
+	float reference;
-	uint32_t mpx_deviation;
 	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

@@ -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;
+	if(runtime->bs412.init == true && (runtime->bs412.sample_rate == config.sample_rate)) {
-	float last_power = 0.0f;
+		reinit_bs412(&runtime->bs412, config.mpx_deviation, config.mpx_power, config.bs412_attack, config.bs412_release, config.bs412_max, config.bs412_gate)
-	uint8_t last_compress = 0;
+	} 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);
-	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;
-
 	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) {