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extract rms detector to separate file

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This commit is contained in:
Chris
2025-07-31 20:25:02 +02:00
parent 9c7d9abc18
commit 989eafebd9
2 changed files with 41 additions and 37 deletions
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55
dynamics/oneknob.h
View File

@@ -1,28 +1,9 @@
#pragma once #pragma once
#include "audio_math.h" #include "audio_math.h"
#include "rms_detector.h"
#include <cmath> #include <cmath>
namespace trnr { namespace trnr {
struct rms_detector {
float alpha;
float rms_squared;
};
inline void rms_init(rms_detector& det, float samplerate, float window_ms)
{
float window_seconds = 0.001f * window_ms;
det.alpha = 1.0f - expf(-1.0f / (samplerate * window_seconds));
det.rms_squared = 0.0f;
}
template <typename sample>
inline sample rms_process(rms_detector& det, sample input)
{
det.rms_squared = (1.0f - det.alpha) * det.rms_squared + det.alpha * (input * input);
return sqrtf(det.rms_squared);
}
struct hp_filter { struct hp_filter {
float a0, a1, b1; float a0, a1, b1;
float z1; // filter state float z1; // filter state
@@ -30,7 +11,7 @@ struct hp_filter {
inline void hp_filter_init(hp_filter& f, float samplerate) inline void hp_filter_init(hp_filter& f, float samplerate)
{ {
float cutoff = 100.0f; const float cutoff = 100.0f;
float w0 = 2.0f * 3.14159265359f * cutoff / samplerate; float w0 = 2.0f * 3.14159265359f * cutoff / samplerate;
float alpha = (1.0f - std::tan(w0 / 2.0f)) / (1.0f + std::tan(w0 / 2.0f)); float alpha = (1.0f - std::tan(w0 / 2.0f)) / (1.0f + std::tan(w0 / 2.0f));
f.a0 = 0.5f * (1.0f + alpha); f.a0 = 0.5f * (1.0f + alpha);
@@ -59,44 +40,45 @@ struct oneknob_comp {
float sidechain_in; float sidechain_in;
}; };
inline void oneknob_init(oneknob_comp& comp, float samplerate, float window_ms) inline void oneknob_init(oneknob_comp& c, float samplerate, float window_ms)
{ {
rms_init(comp.detector, samplerate, window_ms); rms_init(c.detector, samplerate, window_ms);
hp_filter_init(comp.filter, samplerate); hp_filter_init(c.filter, samplerate);
const float attack_ms = 0.2f; const float attack_ms = 0.2f;
const float release_ms = 150.f; const float release_ms = 150.f;
comp.attack_coef = expf(-1.0f / (attack_ms * 1e-6 * samplerate)); // c.amount = 0.f;
comp.release_coef = expf(-1.0f / (release_ms * 1e-3 * samplerate)); c.attack_coef = expf(-1.0f / (attack_ms * 1e-6 * samplerate));
comp.envelope_level = -60.f; c.release_coef = expf(-1.0f / (release_ms * 1e-3 * samplerate));
comp.sidechain_in = 0.f; c.envelope_level = -60.f;
c.sidechain_in = 0.f;
} }
template <typename sample> template <typename sample>
inline void oneknob_process_block(oneknob_comp& comp, sample** audio, int frames) inline void oneknob_process_block(oneknob_comp& c, sample** audio, int frames)
{ {
const float min_user_ratio = 1.0f; const float min_user_ratio = 1.0f;
const float max_user_ratio = 20.0f; const float max_user_ratio = 20.0f;
const float threshold_db = -9.f; const float threshold_db = -9.f;
const float amount = fmaxf(0.0f, fminf(powf(comp.amount, 2.f), 1.0f)); // clamp to [0, 1] const float amount = fmaxf(0.0f, fminf(powf(c.amount, 2.f), 1.0f)); // clamp to [0, 1]
float ratio = min_user_ratio + amount * (max_user_ratio - min_user_ratio); float ratio = min_user_ratio + amount * (max_user_ratio - min_user_ratio);
for (int i = 0; i < frames; ++i) { for (int i = 0; i < frames; ++i) {
float rms_value = rms_process(comp.detector, comp.sidechain_in); float rms_value = rms_process<sample>(c.detector, c.sidechain_in);
float envelope_in = lin_2_db(fmaxf(fabs(rms_value), 1e-20f)); float envelope_in = lin_2_db(fmaxf(fabs(rms_value), 1e-20f));
// attack // attack
if (envelope_in > comp.envelope_level) { if (envelope_in > c.envelope_level) {
comp.envelope_level = envelope_in + comp.attack_coef * (comp.envelope_level - envelope_in); c.envelope_level = envelope_in + c.attack_coef * (c.envelope_level - envelope_in);
} }
// release // release
else { else {
comp.envelope_level = envelope_in + comp.release_coef * (comp.envelope_level - envelope_in); c.envelope_level = envelope_in + c.release_coef * (c.envelope_level - envelope_in);
} }
float x = comp.envelope_level; float x = c.envelope_level;
float y; float y;
if (x < threshold_db) y = x; if (x < threshold_db) y = x;
@@ -110,8 +92,7 @@ inline void oneknob_process_block(oneknob_comp& comp, sample** audio, int frames
// feedback compression // feedback compression
float sum = sqrtf(0.5f * (audio[0][i] * audio[0][i] + audio[1][i] * audio[1][i])); float sum = sqrtf(0.5f * (audio[0][i] * audio[0][i] + audio[1][i] * audio[1][i]));
comp.sidechain_in = hp_filter_process(comp.filter, sum); c.sidechain_in = hp_filter_process(c.filter, sum);
} }
} }
} // namespace trnr } // namespace trnr

23
dynamics/rms_detector.h Normal file
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@@ -0,0 +1,23 @@
#pragma once
#include <cmath>
namespace trnr {
struct rms_detector {
float alpha;
float rms_squared;
};
inline void rms_init(rms_detector& d, float samplerate, float window_ms)
{
float window_seconds = 0.001f * window_ms;
d.alpha = 1.0f - expf(-1.0f / (samplerate * window_seconds));
d.rms_squared = 0.0f;
}
template <typename sample>
inline sample rms_process(rms_detector& d, sample input)
{
d.rms_squared = (1.0f - d.alpha) * d.rms_squared + d.alpha * (input * input);
return sqrtf(d.rms_squared);
}
} // namespace trnr