radio95/fm95
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Code Issues Activity

add some kind of compression to the bs412

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This commit is contained in:
KubaPro010
2025-03-29 19:41:16 +01:00
parent c649df4f24
commit 841bc4aba3
2 changed files with 24 additions and 6 deletions
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26
src/fm95.c
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@@ -13,6 +13,7 @@
#define DEFAULT_SCA_DEVIATION 7000.0f
#define DEFAULT_SCA_CLIPPER_THRESHOLD 1.0f
#define DEFAULT_PREEMPHASIS_TAU 50e-6 // Europe, the freedomers use 75µs
#define DEFAULT_MPX_POWER 3.0f // dbr, this is for BS412, simplest bs412
#include "../lib/constants.h"
#include "../lib/oscillator.h"
@@ -93,6 +94,7 @@ void show_help(char *name) {
" -P,--polar Force Polar Stereo (does not take effect with -m%s)\n"
" -R,--preemp Override preemphasis [default: %.2f µs]\n"
" -V,--calibrate Enable Calibration mode [default: off]\n"
" -p,--power Set the MPX power [default: %.1f]\n"
" -A,--master_vol Set master volume [default: %.3f]\n"
" -v,--audio_vol Set audio volume [default: %.3f]\n"
,name
@@ -120,6 +122,7 @@ void show_help(char *name) {
,DEFAULT_CLIPPER_THRESHOLD
,(DEFAULT_STEREO_POLAR == 1) ? ", default" : ""
,DEFAULT_PREEMPHASIS_TAU/0.000001
,DEFAULT_MPX_POWER
,DEFAULT_MASTER_VOLUME
,DEFAULT_AUDIO_VOLUME
);
@@ -163,6 +166,7 @@ int main(int argc, char **argv) {
float preemphasis_tau = DEFAULT_PREEMPHASIS_TAU;
int calibration_mode = 0;
float mpx_power = DEFAULT_MPX_POWER;
float master_volume = DEFAULT_MASTER_VOLUME;
float audio_volume = DEFAULT_AUDIO_VOLUME;
@@ -170,7 +174,7 @@ int main(int argc, char **argv) {
// #region Parse Arguments
int opt;
const char *short_opt = "s::i:o:M:r:C:f:F:L:c:P::R:VA:v:h";
const char *short_opt = "s::i:o:M:r:C:f:F:L:c:P::R:Vp:A:v:h";
struct option long_opt[] =
{
{"stereo", optional_argument, NULL, 's'},
@@ -186,6 +190,7 @@ int main(int argc, char **argv) {
{"polar", optional_argument, NULL, 'P'},
{"preemp", required_argument, NULL, 'R'},
{"calibrate", no_argument, NULL, 'V'},
{"power", required_argument, NULL, 'p'},
{"master_vol", required_argument, NULL, 'A'},
{"audio_vol", required_argument, NULL, 'v'},
@@ -242,6 +247,9 @@ int main(int argc, char **argv) {
case 'V': // Calibration
calibration_mode = 1;
break;
case 'p': // Power
mpx_power = strtof(optarg, NULL);
break;
case 'A': // Master vol
master_volume = strtof(optarg, NULL);
break;
@@ -477,6 +485,9 @@ int main(int argc, char **argv) {
}
}
float current_audio_level = 1.0f;
int audio_level_adjusted = 0;
for (int i = 0; i < BUFFER_SIZE; i++) {
float l_in = left[i];
float r_in = right[i];
@@ -487,8 +498,8 @@ 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 = hard_clip(ready_l*audio_volume, clipper_threshold);
ready_r = hard_clip(ready_r*audio_volume, clipper_threshold);
ready_l = hard_clip(ready_l*audio_volume*current_audio_level, clipper_threshold);
ready_r = hard_clip(ready_r*audio_volume*current_audio_level, clipper_threshold);
float mono = (ready_l + ready_r) / 2.0f;
output[i] = mono*MONO_VOLUME;
@@ -512,16 +523,19 @@ int main(int argc, char **argv) {
output[i] += (current_rds2_in*rds2_carrier_66)*RDS2_VOLUME;
}
}
if(rds_on || stereo) advance_oscillator(&osc);
if(mpx_on) output[i] += hard_clip(current_mpx_in, MPX_CLIPPER_THRESHOLD)*MPX_VOLUME;
if(sca_on) output[i] += modulate_fm(&sca_mod, hard_clip(current_sca_in, sca_clipper_threshold))*SCA_VOLUME;
float mpower = measure_mpx(&power, output[i]*75000);
if(mpower > 3) {
printf("MPX Power (%f)\n", mpower);
if(mpower > mpx_power) {
current_audio_level *= 0.95f;
audio_level_adjusted = 1;
} else if(audio_level_adjusted && mpower < (mpx_power * 0.9)) {
current_audio_level /= 0.95f;
}
output[i] *= master_volume;
if(rds_on || stereo) advance_oscillator(&osc);
}
if (pa_simple_write(output_device, output, sizeof(output), &pulse_error) < 0) {