agc?

lib/bs412.h

@@ -3,9 +3,9 @@
 
 typedef struct
 {
-    int i;
+	int i;
-    int sample_rate;
+	int sample_rate;
-    double sample;
+	double sample;
 } MPXPowerMeasurement;
 
 float dbr_to_deviation(float dbr);

lib/debug.h

@@ -1,4 +1,4 @@
 #pragma once
 #include <stdio.h>
 #define debug_printf(fmt, ...) \
-    printf("[%s:%d in %s] " fmt, __FILE__, __LINE__, __func__, ##__VA_ARGS__)
+	printf("[%s:%d in %s] " fmt, __FILE__, __LINE__, __func__, ##__VA_ARGS__)

lib/filters.h

@@ -7,12 +7,6 @@
 #include "optimization.h"
 #include "oscillator.h"
 
-#if USE_NEON
-#define LPF_ORDER 20 // neon has to have divisable by 4
-#else
-#define LPF_ORDER 10
-#endif
-
 typedef struct
 {
 	float alpha;

lib/gain_control.c

@@ -0,0 +1,40 @@
+#include "gain_control.h"
+
+void initAGC(AGC* agc, int sampleRate, float targetLevel, float minGain, float maxGain, float attackTime, float releaseTime) {
+	agc->sampleRate = sampleRate;
+	agc->targetLevel = targetLevel;
+	agc->minGain = minGain;
+	agc->maxGain = maxGain;
+	agc->attackTime = attackTime;
+	agc->releaseTime = releaseTime;
+
+	agc->attackCoef = expf(-1.0f / (sampleRate * attackTime));
+	agc->releaseCoef = expf(-1.0f / (sampleRate * releaseTime));
+
+	agc->currentGain = 1.0f;
+	agc->currentLevel = 0.0f;
+
+	agc->rms_buffer = 0.0f;
+}
+
+float process_agc_stereo(AGC* agc, float left, float right, float *right_out) {
+	float sample = (left+right)/2;
+
+	float x2 = sample * sample;
+
+	float rmsAlpha = expf(-1.0f / (agc->sampleRate * 0.04));
+	agc->rms_buffer = rmsAlpha * agc->rms_buffer + (1.0f - rmsAlpha) * x2;
+	float instantLevel = sqrtf(agc->rms_buffer);
+
+	float alpha = (instantLevel > agc->currentLevel) ? agc->attackCoef : agc->releaseCoef;
+	agc->currentLevel = alpha * agc->currentLevel + (1.0f - alpha) * instantLevel;
+
+	float desiredGain = agc->targetLevel / fmaxf(agc->currentLevel, 1e-10f);
+	desiredGain = fminf(fmaxf(desiredGain, agc->minGain), agc->maxGain);
+
+	float gainAlpha = (desiredGain > agc->currentGain) ? agc->attackCoef : agc->releaseCoef;
+	agc->currentGain = gainAlpha * agc->currentGain + (1.0f - gainAlpha) * desiredGain;
+
+	*right_out = right * agc->currentGain;
+	return left * agc->currentGain;
+}

lib/gain_control.h

@@ -0,0 +1,22 @@
+#pragma once
+#include <math.h>
+
+typedef struct {
+	float targetLevel;
+	float maxGain;
+	float minGain;
+	float attackTime;
+	float releaseTime;
+
+	float currentGain;
+	float currentLevel;
+
+	int sampleRate;
+	float attackCoef;
+	float releaseCoef;
+
+	float rms_buffer;
+} AGC;
+
+void initAGC(AGC* agc, int sampleRate, float targetLevel, float minGain, float maxGain, float attackTime, float releaseTime);
+float process_agc_stereo(AGC* agc, float left, float right, float *right_out);

lib/oscillator.c

@@ -23,15 +23,15 @@ float get_oscillator_cos_sample(Oscillator *osc) {
 }
 
 float get_oscillator_sin_multiplier_ni(Oscillator *osc, float multiplier) {
-    float new_phase = osc->phase * multiplier;
+	float new_phase = osc->phase * multiplier;
-    new_phase -= (new_phase >= M_2PI) ? M_2PI : 0.0f;
+	new_phase -= (new_phase >= M_2PI) ? M_2PI : 0.0f;
-    return sinf(new_phase);
+	return sinf(new_phase);
 }
 
 float get_oscillator_cos_multiplier_ni(Oscillator *osc, float multiplier) {
 	float new_phase = osc->phase * multiplier;
-    new_phase -= (new_phase >= M_2PI) ? M_2PI : 0.0f;
+	new_phase -= (new_phase >= M_2PI) ? M_2PI : 0.0f;
-    return cosf(new_phase);
+	return cosf(new_phase);
 }
 
 void advance_oscillator(Oscillator *osc) {

src/dcf95.c

@@ -133,41 +133,41 @@ void calculate_dcf77_bits(time_t now, int *bits) {
 	bits[20] = 1;
 
 	int minutes = t->tm_min;
-    for (int i = 0; i < 4; i++) {
+	for (int i = 0; i < 4; i++) {
-        bits[21 + i] = (minutes % 10 >> i) & 1;
+		bits[21 + i] = (minutes % 10 >> i) & 1;
-    }
+	}
-    for (int i = 0; i < 3; i++) {
+	for (int i = 0; i < 3; i++) {
-        bits[25 + i] = (minutes / 10 >> i) & 1;
+		bits[25 + i] = (minutes / 10 >> i) & 1;
-    }
+	}
 
-    int minute_parity = 0;
+	int minute_parity = 0;
-    for (int i = 21; i <= 27; i++) {
+	for (int i = 21; i <= 27; i++) {
-        minute_parity ^= bits[i];
+		minute_parity ^= bits[i];
-    }
+	}
-    bits[28] = minute_parity;
+	bits[28] = minute_parity;
 
 	int hours = t->tm_hour;
 	if(cest) hours += 1;
 	for (int i = 0; i < 4; i++) {
-        bits[29 + i] = (hours % 10 >> i) & 1;
+		bits[29 + i] = (hours % 10 >> i) & 1;
-    }
+	}
-    for (int i = 0; i < 2; i++) {
+	for (int i = 0; i < 2; i++) {
-        bits[33 + i] = (hours / 10 >> i) & 1;
+		bits[33 + i] = (hours / 10 >> i) & 1;
-    }
+	}
 
 	int hour_parity = 0;
-    for (int i = 29; i <= 34; i++) {
+	for (int i = 29; i <= 34; i++) {
-        hour_parity ^= bits[i];
+		hour_parity ^= bits[i];
-    }
+	}
-    bits[35] = hour_parity;
+	bits[35] = hour_parity;
 
 	int day = t->tm_mday;
 	for (int i = 0; i < 4; i++) {
-        bits[36 + i] = (day % 10 >> i) & 1;
+		bits[36 + i] = (day % 10 >> i) & 1;
-    }
+	}
-    for (int i = 0; i < 2; i++) {
+	for (int i = 0; i < 2; i++) {
-        bits[40 + i] = (day / 10 >> i) & 1;
+		bits[40 + i] = (day / 10 >> i) & 1;
-    }
+	}
 
 	int dow = t->tm_wday == 0 ? 7 : t->tm_wday;
 	bits[42] = dow & 0x01;
@@ -176,17 +176,17 @@ void calculate_dcf77_bits(time_t now, int *bits) {
 
 	int month = t->tm_mon + 1;
 	for (int i = 0; i < 4; i++) {
-        bits[45 + i] = (month % 10 >> i) & 1;
+		bits[45 + i] = (month % 10 >> i) & 1;
-    }
+	}
 	bits[49] = (month / 10) & 0x01;
 
 	int year = t->tm_year % 100;
 	for (int i = 0; i < 4; i++) {
-    	bits[50 + i] = (year % 10 >> i) & 1;
+		bits[50 + i] = (year % 10 >> i) & 1;
 	}
 	for (int i = 0; i < 4; i++) {
-        bits[54 + i] = (year / 10 >> i) & 1;
+		bits[54 + i] = (year / 10 >> i) & 1;
-    }
+	}
 
 	int year_parity = 0;
 	for (int i = 36; i <= 57; i++) {

src/fm95.c

@@ -21,6 +21,7 @@
 #include "../lib/fm_modulator.h"
 #include "../lib/optimization.h"
 #include "../lib/bs412.h"
+#include "../lib/gain_control.h"
 
 #define DEFAULT_SAMPLE_RATE 192000
 
@@ -453,6 +454,10 @@ int main(int argc, char **argv) {
 	MPXPowerMeasurement mpx_only_power;
 	init_modulation_power_measure(&mpx_only_power, sample_rate);
 
+	AGC agc;
+	void initAGC(AGC* agc, int sampleRate, float targetLevel, float minGain, float maxGain, float attackTime, float releaseTime);
+	initAGC(&agc, sample_rate, 0.707f, 0.25f, 2.5f, 0.01f, 0.4f);
+
 	signal(SIGINT, stop);
 	signal(SIGTERM, stop);
 
@@ -512,6 +517,7 @@ int main(int argc, char **argv) {
 
 			float ready_l = apply_preemphasis(&preemp_l, l_in);
 			float ready_r = apply_preemphasis(&preemp_r, r_in);
+			ready_l = process_agc_stereo(&agc, ready_l, ready_r, &ready_r);
 			ready_l = hard_clip(ready_l*audio_volume, clipper_threshold);
 			ready_r = hard_clip(ready_r*audio_volume, clipper_threshold);