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introduce soft clipping into bs412

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KubaPro010
2025-08-03 16:03:15 +02:00
parent de8f4652a4
commit db61f78e5a
1 changed files with 13 additions and 0 deletions
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13
filter/bs412.c
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@@ -26,6 +26,15 @@ void init_bs412(BS412Compressor* mpx, float mpx_deviation, float target_power, f
#endif #endif
} }
float soft_clip_tanh(float sample, float threshold) {
if (fabsf(sample) <= threshold) {
return sample; // Linear region
}
float sign = (sample >= 0) ? 1.0f : -1.0f;
float excess = fabsf(sample) - threshold;
return sign * (threshold + tanhf(excess) * (1.0f - threshold));
}
float bs412_compress(BS412Compressor* mpx, float sample) { float bs412_compress(BS412Compressor* mpx, float sample) {
mpx->average += sample * sample * mpx->mpx_deviation * mpx->mpx_deviation; mpx->average += sample * sample * mpx->mpx_deviation * mpx->mpx_deviation;
mpx->average_counter++; mpx->average_counter++;
@@ -57,5 +66,9 @@ float bs412_compress(BS412Compressor* mpx, float sample) {
mpx->gain = fmaxf(0.0f, fminf(mpx->max, mpx->gain)); mpx->gain = fmaxf(0.0f, fminf(mpx->max, mpx->gain));
float output_sample = sample * mpx->gain;
float limit_threshold = dbr_to_deviation(mpx->target + 0.1f) / mpx->mpx_deviation;
output_sample = soft_clip_tanh(output_sample, limit_threshold);
return sample * mpx->gain; return sample * mpx->gain;
} }