1/**************************************************************************/
2/* audio_effect_limiter.cpp */
3/**************************************************************************/
4/* This file is part of: */
5/* GODOT ENGINE */
6/* https://godotengine.org */
7/**************************************************************************/
8/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
9/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
10/* */
11/* Permission is hereby granted, free of charge, to any person obtaining */
12/* a copy of this software and associated documentation files (the */
13/* "Software"), to deal in the Software without restriction, including */
14/* without limitation the rights to use, copy, modify, merge, publish, */
15/* distribute, sublicense, and/or sell copies of the Software, and to */
16/* permit persons to whom the Software is furnished to do so, subject to */
17/* the following conditions: */
18/* */
19/* The above copyright notice and this permission notice shall be */
20/* included in all copies or substantial portions of the Software. */
21/* */
22/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
23/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
24/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
25/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
26/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
27/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
28/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
29/**************************************************************************/
30
31#include "audio_effect_limiter.h"
32
33void AudioEffectLimiterInstance::process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count) {
34 float threshdb = base->threshold;
35 float ceiling = Math::db_to_linear(base->ceiling);
36 float ceildb = base->ceiling;
37 float makeup = Math::db_to_linear(ceildb - threshdb);
38 float sc = -base->soft_clip;
39 float scv = Math::db_to_linear(sc);
40 float peakdb = ceildb + 25;
41 float scmult = Math::abs((ceildb - sc) / (peakdb - sc));
42
43 for (int i = 0; i < p_frame_count; i++) {
44 float spl0 = p_src_frames[i].l;
45 float spl1 = p_src_frames[i].r;
46 spl0 = spl0 * makeup;
47 spl1 = spl1 * makeup;
48 float sign0 = (spl0 < 0.0 ? -1.0 : 1.0);
49 float sign1 = (spl1 < 0.0 ? -1.0 : 1.0);
50 float abs0 = Math::abs(spl0);
51 float abs1 = Math::abs(spl1);
52 float overdb0 = Math::linear_to_db(abs0) - ceildb;
53 float overdb1 = Math::linear_to_db(abs1) - ceildb;
54
55 if (abs0 > scv) {
56 spl0 = sign0 * (scv + Math::db_to_linear(overdb0 * scmult));
57 }
58 if (abs1 > scv) {
59 spl1 = sign1 * (scv + Math::db_to_linear(overdb1 * scmult));
60 }
61
62 spl0 = MIN(ceiling, Math::abs(spl0)) * (spl0 < 0.0 ? -1.0 : 1.0);
63 spl1 = MIN(ceiling, Math::abs(spl1)) * (spl1 < 0.0 ? -1.0 : 1.0);
64
65 p_dst_frames[i].l = spl0;
66 p_dst_frames[i].r = spl1;
67 }
68}
69
70Ref<AudioEffectInstance> AudioEffectLimiter::instantiate() {
71 Ref<AudioEffectLimiterInstance> ins;
72 ins.instantiate();
73 ins->base = Ref<AudioEffectLimiter>(this);
74
75 return ins;
76}
77
78void AudioEffectLimiter::set_threshold_db(float p_threshold) {
79 threshold = p_threshold;
80}
81
82float AudioEffectLimiter::get_threshold_db() const {
83 return threshold;
84}
85
86void AudioEffectLimiter::set_ceiling_db(float p_ceiling) {
87 ceiling = p_ceiling;
88}
89
90float AudioEffectLimiter::get_ceiling_db() const {
91 return ceiling;
92}
93
94void AudioEffectLimiter::set_soft_clip_db(float p_soft_clip) {
95 soft_clip = p_soft_clip;
96}
97
98float AudioEffectLimiter::get_soft_clip_db() const {
99 return soft_clip;
100}
101
102void AudioEffectLimiter::set_soft_clip_ratio(float p_soft_clip) {
103 soft_clip_ratio = p_soft_clip;
104}
105
106float AudioEffectLimiter::get_soft_clip_ratio() const {
107 return soft_clip_ratio;
108}
109
110void AudioEffectLimiter::_bind_methods() {
111 ClassDB::bind_method(D_METHOD("set_ceiling_db", "ceiling"), &AudioEffectLimiter::set_ceiling_db);
112 ClassDB::bind_method(D_METHOD("get_ceiling_db"), &AudioEffectLimiter::get_ceiling_db);
113
114 ClassDB::bind_method(D_METHOD("set_threshold_db", "threshold"), &AudioEffectLimiter::set_threshold_db);
115 ClassDB::bind_method(D_METHOD("get_threshold_db"), &AudioEffectLimiter::get_threshold_db);
116
117 ClassDB::bind_method(D_METHOD("set_soft_clip_db", "soft_clip"), &AudioEffectLimiter::set_soft_clip_db);
118 ClassDB::bind_method(D_METHOD("get_soft_clip_db"), &AudioEffectLimiter::get_soft_clip_db);
119
120 ClassDB::bind_method(D_METHOD("set_soft_clip_ratio", "soft_clip"), &AudioEffectLimiter::set_soft_clip_ratio);
121 ClassDB::bind_method(D_METHOD("get_soft_clip_ratio"), &AudioEffectLimiter::get_soft_clip_ratio);
122
123 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "ceiling_db", PROPERTY_HINT_RANGE, "-20,-0.1,0.1,suffix:dB"), "set_ceiling_db", "get_ceiling_db");
124 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "threshold_db", PROPERTY_HINT_RANGE, "-30,0,0.1,suffix:dB"), "set_threshold_db", "get_threshold_db");
125 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "soft_clip_db", PROPERTY_HINT_RANGE, "0,6,0.1,suffix:dB"), "set_soft_clip_db", "get_soft_clip_db");
126 ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "soft_clip_ratio", PROPERTY_HINT_RANGE, "3,20,0.1"), "set_soft_clip_ratio", "get_soft_clip_ratio");
127}
128
129AudioEffectLimiter::AudioEffectLimiter() {
130 threshold = 0;
131 ceiling = -0.1;
132 soft_clip = 2;
133 soft_clip_ratio = 10;
134}
135