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45 lines
1.5 KiB
C
45 lines
1.5 KiB
C
#include "stereo_encoder.h"
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// Multiplier is the multiplier to get to 19 khz
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void init_stereo_encoder(StereoEncoder* st, uint8_t multiplier, Oscillator* osc, float audio_volume, float pilot_volume) {
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st->multiplier = multiplier;
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st->osc = osc;
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st->pilot_volume = pilot_volume;
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st->audio_volume = audio_volume;
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#ifdef STEREO_SSB
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init_delay_line(&st->delay, osc->sample_rate);
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set_delay_line(&st->delay, STEREO_SSB*2+1);
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#endif
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}
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float stereo_encode(StereoEncoder* st, uint8_t enabled, float left, float right, firhilbf *hilbert) {
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float mid = (left+right) * 0.5f;
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if(!enabled) return mid * st->audio_volume;
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#ifdef STEREO_SSB
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mid = delay_line(&st->delay, mid);
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#endif
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float half_audio = st->audio_volume * 0.5f;
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float side = (left-right) * 0.5f;
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#ifdef STEREO_SSB
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float complex stereo_hilbert;
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firhilbf_r2c_execute(*hilbert, side, &stereo_hilbert);
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float signalx2cos = get_oscillator_cos_multiplier_ni(st->osc, st->multiplier * 2.0f);
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#endif
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float signalx1 = get_oscillator_sin_multiplier_ni(st->osc, st->multiplier);
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float signalx2 = get_oscillator_sin_multiplier_ni(st->osc, st->multiplier * 2.0f);
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#ifdef STEREO_SSB
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float stereo = (crealf(stereo_hilbert) * signalx2cos) + (cimagf(stereo_hilbert) * signalx2);
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return (mid*half_audio) + (signalx1*st->pilot_volume) + (stereo * half_audio);
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#else
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return (mid*half_audio) + (signalx1*st->pilot_volume) + ((side*signalx2) * half_audio);
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#endif
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}
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void exit_stereo_encoder(StereoEncoder* st) {
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exit_delay_line(&st->delay);
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} |