1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
|
/**
* OpenAL cross platform audio library
* Copyright (C) 2013 by Anis A. Hireche
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
* Or go to http://www.gnu.org/copyleft/lgpl.html
*/
#include "config.h"
#include <cstdlib>
#include "alMain.h"
#include "alcontext.h"
#include "alu.h"
#include "alAuxEffectSlot.h"
#include "alError.h"
#include "vecmat.h"
namespace {
#define AMP_ENVELOPE_MIN 0.5f
#define AMP_ENVELOPE_MAX 2.0f
#define ATTACK_TIME 0.1f /* 100ms to rise from min to max */
#define RELEASE_TIME 0.2f /* 200ms to drop from max to min */
struct CompressorState final : public EffectState {
/* Effect gains for each channel */
ALfloat mGain[MAX_AMBI_CHANNELS][MAX_OUTPUT_CHANNELS]{};
/* Effect parameters */
ALboolean mEnabled{AL_TRUE};
ALfloat mAttackMult{1.0f};
ALfloat mReleaseMult{1.0f};
ALfloat mEnvFollower{1.0f};
ALboolean deviceUpdate(const ALCdevice *device) override;
void update(const ALCcontext *context, const ALeffectslot *slot, const EffectProps *props, const EffectTarget target) override;
void process(const ALsizei samplesToDo, const FloatBufferLine *RESTRICT samplesIn, const ALsizei numInput, const al::span<FloatBufferLine> samplesOut) override;
DEF_NEWDEL(CompressorState)
};
ALboolean CompressorState::deviceUpdate(const ALCdevice *device)
{
/* Number of samples to do a full attack and release (non-integer sample
* counts are okay).
*/
const ALfloat attackCount = static_cast<ALfloat>(device->Frequency) * ATTACK_TIME;
const ALfloat releaseCount = static_cast<ALfloat>(device->Frequency) * RELEASE_TIME;
/* Calculate per-sample multipliers to attack and release at the desired
* rates.
*/
mAttackMult = std::pow(AMP_ENVELOPE_MAX/AMP_ENVELOPE_MIN, 1.0f/attackCount);
mReleaseMult = std::pow(AMP_ENVELOPE_MIN/AMP_ENVELOPE_MAX, 1.0f/releaseCount);
return AL_TRUE;
}
void CompressorState::update(const ALCcontext* UNUSED(context), const ALeffectslot *slot, const EffectProps *props, const EffectTarget target)
{
mEnabled = props->Compressor.OnOff;
mOutBuffer = target.Main->Buffer;
mOutChannels = target.Main->NumChannels;
for(ALsizei i{0};i < slot->Wet.NumChannels;++i)
{
auto coeffs = GetAmbiIdentityRow(i);
ComputePanGains(target.Main, coeffs.data(), slot->Params.Gain, mGain[i]);
}
}
void CompressorState::process(const ALsizei samplesToDo, const FloatBufferLine *RESTRICT samplesIn, const ALsizei numInput, const al::span<FloatBufferLine> samplesOut)
{
for(ALsizei base{0};base < samplesToDo;)
{
ALfloat gains[256];
const ALsizei td{mini(256, samplesToDo-base)};
/* Generate the per-sample gains from the signal envelope. */
ALfloat env{mEnvFollower};
if(mEnabled)
{
for(ALsizei i{0};i < td;++i)
{
/* Clamp the absolute amplitude to the defined envelope limits,
* then attack or release the envelope to reach it.
*/
const ALfloat amplitude{clampf(std::fabs(samplesIn[0][base+i]), AMP_ENVELOPE_MIN,
AMP_ENVELOPE_MAX)};
if(amplitude > env)
env = minf(env*mAttackMult, amplitude);
else if(amplitude < env)
env = maxf(env*mReleaseMult, amplitude);
/* Apply the reciprocal of the envelope to normalize the volume
* (compress the dynamic range).
*/
gains[i] = 1.0f / env;
}
}
else
{
/* Same as above, except the amplitude is forced to 1. This helps
* ensure smooth gain changes when the compressor is turned on and
* off.
*/
for(ALsizei i{0};i < td;++i)
{
const ALfloat amplitude{1.0f};
if(amplitude > env)
env = minf(env*mAttackMult, amplitude);
else if(amplitude < env)
env = maxf(env*mReleaseMult, amplitude);
gains[i] = 1.0f / env;
}
}
mEnvFollower = env;
/* Now compress the signal amplitude to output. */
ASSUME(numInput > 0);
for(ALsizei j{0};j < numInput;j++)
{
const ALfloat *outgains{mGain[j]};
for(FloatBufferLine &output : samplesOut)
{
const ALfloat gain{*(outgains++)};
if(!(std::fabs(gain) > GAIN_SILENCE_THRESHOLD))
continue;
for(ALsizei i{0};i < td;i++)
output[base+i] += samplesIn[j][base+i] * gains[i] * gain;
}
}
base += td;
}
}
void Compressor_setParami(EffectProps *props, ALCcontext *context, ALenum param, ALint val)
{
switch(param)
{
case AL_COMPRESSOR_ONOFF:
if(!(val >= AL_COMPRESSOR_MIN_ONOFF && val <= AL_COMPRESSOR_MAX_ONOFF))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Compressor state out of range");
props->Compressor.OnOff = val;
break;
default:
alSetError(context, AL_INVALID_ENUM, "Invalid compressor integer property 0x%04x",
param);
}
}
void Compressor_setParamiv(EffectProps *props, ALCcontext *context, ALenum param, const ALint *vals)
{ Compressor_setParami(props, context, param, vals[0]); }
void Compressor_setParamf(EffectProps*, ALCcontext *context, ALenum param, ALfloat)
{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float property 0x%04x", param); }
void Compressor_setParamfv(EffectProps*, ALCcontext *context, ALenum param, const ALfloat*)
{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float-vector property 0x%04x", param); }
void Compressor_getParami(const EffectProps *props, ALCcontext *context, ALenum param, ALint *val)
{
switch(param)
{
case AL_COMPRESSOR_ONOFF:
*val = props->Compressor.OnOff;
break;
default:
alSetError(context, AL_INVALID_ENUM, "Invalid compressor integer property 0x%04x",
param);
}
}
void Compressor_getParamiv(const EffectProps *props, ALCcontext *context, ALenum param, ALint *vals)
{ Compressor_getParami(props, context, param, vals); }
void Compressor_getParamf(const EffectProps*, ALCcontext *context, ALenum param, ALfloat*)
{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float property 0x%04x", param); }
void Compressor_getParamfv(const EffectProps*, ALCcontext *context, ALenum param, ALfloat*)
{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float-vector property 0x%04x", param); }
DEFINE_ALEFFECT_VTABLE(Compressor);
struct CompressorStateFactory final : public EffectStateFactory {
EffectState *create() override { return new CompressorState{}; }
EffectProps getDefaultProps() const noexcept override;
const EffectVtable *getEffectVtable() const noexcept override { return &Compressor_vtable; }
};
EffectProps CompressorStateFactory::getDefaultProps() const noexcept
{
EffectProps props{};
props.Compressor.OnOff = AL_COMPRESSOR_DEFAULT_ONOFF;
return props;
}
} // namespace
EffectStateFactory *CompressorStateFactory_getFactory()
{
static CompressorStateFactory CompressorFactory{};
return &CompressorFactory;
}
|
