Added Audio Limiter bus effect, and sidechain ability to compressor.

1 files changed, 124 insertions, 0 deletions

diff --git a/servers/audio/effects/audio_effect_limiter.cpp b/servers/audio/effects/audio_effect_limiter.cpp
new file mode 100644
index 0000000000..5cd02682ab
--- /dev/null
+++ b/servers/audio/effects/audio_effect_limiter.cpp
@@ -0,0 +1,124 @@
+#include "audio_effect_limiter.h"
+
+void AudioEffectLimiterInstance::process(const AudioFrame *p_src_frames,AudioFrame *p_dst_frames,int p_frame_count) {
+
+	float thresh = Math::db2linear(base->treshold);
+	float threshdb = base->treshold;
+	float ceiling = Math::db2linear(base->ceiling);
+	float ceildb = base->ceiling;
+	float makeup = Math::db2linear(ceildb - threshdb);
+	float makeupdb = ceildb - threshdb;
+	float sc = -base->soft_clip;
+	float scv = Math::db2linear(sc);
+	float sccomp = Math::db2linear(-sc);
+	float peakdb = ceildb + 25;
+	float peaklvl = Math::db2linear(peakdb);
+	float scratio = base->soft_clip_ratio;
+	float scmult = Math::abs((ceildb - sc) / (peakdb - sc));
+
+	for(int i=0;i<p_frame_count;i++) {
+
+		float spl0 = p_src_frames[i].l;
+		float spl1 = p_src_frames[i].r;
+		spl0 = spl0 * makeup;
+		spl1 = spl1 * makeup;
+		float sign0 = (spl0 < 0.0 ? -1.0 : 1.0 );
+		float sign1 = (spl1 < 0.0 ? -1.0 : 1.0 );
+		float abs0 = Math::abs(spl0);
+		float abs1 = Math::abs(spl1);
+		float overdb0 = Math::linear2db(abs0) - ceildb;
+		float overdb1 = Math::linear2db(abs1) - ceildb;
+
+		if (abs0 > scv)
+		{
+			spl0 = sign0 * (scv + Math::db2linear(overdb0 * scmult));
+		}
+		if (abs1 > scv)
+		{
+			spl1 = sign1 * (scv + Math::db2linear(overdb1 * scmult));
+		}
+
+		spl0 = MIN(ceiling, Math::abs(spl0)) * (spl0 < 0.0 ? -1.0 : 1.0);
+		spl1 = MIN(ceiling, Math::abs(spl1)) * (spl1 < 0.0 ? -1.0 : 1.0);
+
+		p_dst_frames[i].l = spl0;
+		p_dst_frames[i].r = spl1;
+	}
+
+}
+
+
+Ref<AudioEffectInstance> AudioEffectLimiter::instance() {
+	Ref<AudioEffectLimiterInstance> ins;
+	ins.instance();
+	ins->base=Ref<AudioEffectLimiter>(this);
+
+	return ins;
+}
+
+
+void AudioEffectLimiter::set_treshold_db(float p_treshold) {
+
+	treshold=p_treshold;
+}
+
+float AudioEffectLimiter::get_treshold_db() const{
+
+	return treshold;
+}
+
+void AudioEffectLimiter::set_ceiling_db(float p_ceiling){
+
+	ceiling=p_ceiling;
+}
+float AudioEffectLimiter::get_ceiling_db() const{
+
+	return ceiling;
+}
+
+void AudioEffectLimiter::set_soft_clip_db(float p_soft_clip){
+
+	soft_clip=p_soft_clip;
+}
+float AudioEffectLimiter::get_soft_clip_db() const{
+
+	return soft_clip;
+}
+
+void AudioEffectLimiter::set_soft_clip_ratio(float p_soft_clip){
+
+	soft_clip_ratio=p_soft_clip;
+}
+float AudioEffectLimiter::get_soft_clip_ratio() const{
+
+	return soft_clip;
+}
+
+
+void AudioEffectLimiter::_bind_methods() {
+
+	ClassDB::bind_method(_MD("set_ceiling_db","ceiling"),&AudioEffectLimiter::set_ceiling_db);
+	ClassDB::bind_method(_MD("get_ceiling_db"),&AudioEffectLimiter::get_ceiling_db);
+
+	ClassDB::bind_method(_MD("set_treshold_db","treshold"),&AudioEffectLimiter::set_treshold_db);
+	ClassDB::bind_method(_MD("get_treshold_db"),&AudioEffectLimiter::get_treshold_db);
+
+	ClassDB::bind_method(_MD("set_soft_clip_db","soft_clip"),&AudioEffectLimiter::set_soft_clip_db);
+	ClassDB::bind_method(_MD("get_soft_clip_db"),&AudioEffectLimiter::get_soft_clip_db);
+
+	ClassDB::bind_method(_MD("set_soft_clip_ratio","soft_clip"),&AudioEffectLimiter::set_soft_clip_ratio);
+	ClassDB::bind_method(_MD("get_soft_clip_ratio"),&AudioEffectLimiter::get_soft_clip_ratio);
+
+	ADD_PROPERTY(PropertyInfo(Variant::REAL,"ceiling_db",PROPERTY_HINT_RANGE,"-20,-0.1,0.1"),_SCS("set_ceiling_db"),_SCS("get_ceiling_db"));
+	ADD_PROPERTY(PropertyInfo(Variant::REAL,"treshold_db",PROPERTY_HINT_RANGE,"-30,0,0.1"),_SCS("set_treshold_db"),_SCS("get_treshold_db"));
+	ADD_PROPERTY(PropertyInfo(Variant::REAL,"soft_clip_db",PROPERTY_HINT_RANGE,"0,6,0.1"),_SCS("set_soft_clip_db"),_SCS("get_soft_clip_db"));
+	ADD_PROPERTY(PropertyInfo(Variant::REAL,"soft_clip_ratio",PROPERTY_HINT_RANGE,"3,20,0.1"),_SCS("set_soft_clip_ratio"),_SCS("get_soft_clip_ratio"));
+}
+
+AudioEffectLimiter::AudioEffectLimiter()
+{
+	treshold=0;
+	ceiling=-0.1;
+	soft_clip=2;
+	soft_clip_ratio=10;
+}