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disable filters if their values are 0, add lpf_cutoff config and also rechain the bs412 compressor, as mpx_in used to be pure pass, but now it is added before the bs412 compressor

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KubaPro010
2025-07-10 18:51:32 +02:00
parent 6b0dd96de5
commit e82c617dab
2 changed files with 28 additions and 17 deletions
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43
src/fm95.c
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@@ -88,6 +88,7 @@ typedef struct
float bs412_attack;
float bs412_release;
float bs412_max;
float lpf_cutoff;
} FM95_Config;
typedef struct
@@ -160,8 +161,8 @@ int run_fm95(const FM95_Config config, FM95_Runtime* runtime) {
init_oscillator(&osc, (config.stereo == 2) ? 7812.5 : 4750, config.sample_rate);
iirfilt_rrrf lpf_l, lpf_r;
lpf_l = iirfilt_rrrf_create_prototype(LIQUID_IIRDES_CHEBY2, LIQUID_IIRDES_LOWPASS, LIQUID_IIRDES_SOS, config.lpf_order, (15000.0f/config.sample_rate), 0.0f, 1.0f, 60.0f);
lpf_r = iirfilt_rrrf_create_prototype(LIQUID_IIRDES_CHEBY2, LIQUID_IIRDES_LOWPASS, LIQUID_IIRDES_SOS, config.lpf_order, (15000.0f/config.sample_rate), 0.0f, 1.0f, 60.0f);
lpf_l = iirfilt_rrrf_create_prototype(LIQUID_IIRDES_CHEBY2, LIQUID_IIRDES_LOWPASS, LIQUID_IIRDES_SOS, config.lpf_order, (config.lpf_cutoff/config.sample_rate), 0.0f, 1.0f, 60.0f);
lpf_r = iirfilt_rrrf_create_prototype(LIQUID_IIRDES_CHEBY2, LIQUID_IIRDES_LOWPASS, LIQUID_IIRDES_SOS, config.lpf_order, (config.lpf_cutoff/config.sample_rate), 0.0f, 1.0f, 60.0f);
ResistorCapacitor preemp_l, preemp_r;
init_preemphasis(&preemp_l, config.preemphasis, config.sample_rate, config.preemp_unity_freq);
@@ -211,21 +212,23 @@ int run_fm95(const FM95_Config config, FM95_Runtime* runtime) {
for (uint16_t i = 0; i < BUFFER_SIZE; i++) {
float mpx = 0.0f;
float ready_l = apply_preemphasis(&preemp_l, audio_stereo_input[2*i+0]*config.audio_preamp);
float ready_r = apply_preemphasis(&preemp_r, audio_stereo_input[2*i+1]*config.audio_preamp);
iirfilt_rrrf_execute(lpf_l, ready_l, &ready_l);
iirfilt_rrrf_execute(lpf_r, ready_r, &ready_r);
float l = audio_stereo_input[2*i+0]*config.audio_preamp;
float r = audio_stereo_input[2*i+1]*config.audio_preamp;
if(config.preemphasis != 0) l = apply_preemphasis(&preemp_l, l);
if(config.preemphasis != 0) r = apply_preemphasis(&preemp_r, r);
if(config.lpf_cutoff != 0) iirfilt_rrrf_execute(lpf_l, l, &l);
if(config.lpf_cutoff != 0) iirfilt_rrrf_execute(lpf_r, r, &r);
float agc_gain = process_agc(&agc, ((ready_l + ready_r) * 0.5f));
ready_l *= agc_gain;
ready_r *= agc_gain;
float agc_gain = process_agc(&agc, ((l + r) * 0.5f));
l *= agc_gain;
r *= agc_gain;
ready_l = hard_clip(ready_l*config.audio_volume, config.clipper_threshold);
ready_r = hard_clip(ready_r*config.audio_volume, config.clipper_threshold);
l = hard_clip(l*config.audio_volume, config.clipper_threshold);
r = hard_clip(r*config.audio_volume, config.clipper_threshold);
mpx = stereo_encode(&stencode, config.stereo, ready_l, ready_r);
mpx = stereo_encode(&stencode, config.stereo, l, r);
if(rds_on && !(config.stereo == 2)) {
if(rds_on && !(config.stereo == 2)) { // disable rds on polar stereo
for(uint8_t stream = 0; stream < config.rds_streams; stream++) {
uint8_t osc_stream = 12+stream; // If the osc is a 4750 sine wave, then doing this would mean that stream 0 is 12, so 57 khz
if(osc_stream == 13) osc_stream++; // 61.75 KHz is not used, idk why but would be cool if it was
@@ -233,9 +236,10 @@ int run_fm95(const FM95_Config config, FM95_Runtime* runtime) {
}
}
mpx = bs412_compress(&bs412, mpx);
output[i] = hard_clip(tilt(&tilter, (mpx_in[i]+mpx))*config.master_volume, 1.0); // Ensure peak deviation of 75 khz, assuming we're calibrated correctly (lower)
mpx = bs412_compress(&bs412, mpx+mpx_in[i]);
if(config.tilt != 0) mpx = tilt(&tilter, mpx);
output[i] = hard_clip(mpx*config.master_volume, 1.0); // Ensure peak deviation of 75 khz, assuming we're calibrated correctly (lower)
advance_oscillator(&osc);
}
@@ -356,6 +360,12 @@ static int config_handler(void* user, const char* section, const char* name, con
pconfig->tilt = strtof(value, NULL);
} else if(MATCH("advanced", "bs412_max")) {
pconfig->bs412_max = strtof(value, NULL);
} else if(MATCH("advanced", "lpf_cutoff")) {
pconfig->lpf_cutoff = strtof(value, NULL);
if(pconfig->lpf_cutoff > (pconfig->sample_rate * 0.5)) {
pconfig->lpf_cutoff = (pconfig->sample_rate * 0.5);
fprintf(stderr, "LPF cutoff over niquist, limiting.\n");
}
} else {
return 0; // Unknown section/name
}
@@ -465,6 +475,7 @@ int main(int argc, char **argv) {
.bs412_attack = 0.03f,
.bs412_release = 0.02,
.bs412_max = 1.0f,
.lpf_cutoff = 15000,
};
FM95_DeviceNames dv_names = {