Alc/effects/compressor.c

   1 /**
   2  * OpenAL cross platform audio library
   3  * Copyright (C) 2013 by Anis A. Hireche
   4  * This library is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU Library General Public
   6  *  License as published by the Free Software Foundation; either
   7  *  version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *  Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  *  License along with this library; if not, write to the
  16  *  Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  * Or go to http://www.gnu.org/copyleft/lgpl.html
  19  */
  20
  21 #include <stdlib.h>
  22
  23 #include "config.h"
  24 #include "alError.h"
  25 #include "alMain.h"
  26 #include "alAuxEffectSlot.h"
  27 #include "alu.h"
  28
  29
  30 typedef struct ALcompressorState {
  31     DERIVE_FROM_TYPE(ALeffectState);
  32
  33     /* Effect gains for each channel */
  34     ALfloat Gain[MAX_OUTPUT_CHANNELS];
  35
  36     /* Effect parameters */
  37     ALboolean Enabled;
  38     ALfloat AttackRate;
  39     ALfloat ReleaseRate;
  40     ALfloat GainCtrl;
  41 } ALcompressorState;
  42
  43 static ALvoid ALcompressorState_Destruct(ALcompressorState *UNUSED(state))
  44 {
  45 }
  46
  47 static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device)
  48 {
  49     const ALfloat attackTime = device->Frequency * 0.2f; /* 200ms Attack */
  50     const ALfloat releaseTime = device->Frequency * 0.4f; /* 400ms Release */
  51
  52     state->AttackRate = 1.0f / attackTime;
  53     state->ReleaseRate = 1.0f / releaseTime;
  54
  55     return AL_TRUE;
  56 }
  57
  58 static ALvoid ALcompressorState_update(ALcompressorState *state, ALCdevice *device, const ALeffectslot *slot)
  59 {
  60     state->Enabled = slot->EffectProps.Compressor.OnOff;
  61
  62     ComputeAmbientGains(device, slot->Gain, state->Gain);
  63 }
  64
  65 static ALvoid ALcompressorState_process(ALcompressorState *state, ALuint SamplesToDo, const ALfloat *SamplesIn, ALfloat (*SamplesOut)[BUFFERSIZE], ALuint NumChannels)
  66 {
  67     ALuint it, kt;
  68     ALuint base;
  69
  70     for(base = 0;base < SamplesToDo;)
  71     {
  72         ALfloat temps[256];
  73         ALuint td = minu(256, SamplesToDo-base);
  74
  75         if(state->Enabled)
  76         {
  77             ALfloat output, smp, amplitude;
  78             ALfloat gain = state->GainCtrl;
  79
  80             for(it = 0;it < td;it++)
  81             {
  82                 smp = SamplesIn[it+base];
  83
  84                 amplitude = fabsf(smp);
  85                 if(amplitude > gain)
  86                     gain = minf(gain+state->AttackRate, amplitude);
  87                 else if(amplitude < gain)
  88                     gain = maxf(gain-state->ReleaseRate, amplitude);
  89                 output = 1.0f / clampf(gain, 0.5f, 2.0f);
  90
  91                 temps[it] = smp * output;
  92             }
  93
  94             state->GainCtrl = gain;
  95         }
  96         else
  97         {
  98             ALfloat output, smp, amplitude;
  99             ALfloat gain = state->GainCtrl;
 100
 101             for(it = 0;it < td;it++)
 102             {
 103                 smp = SamplesIn[it+base];
 104
 105                 amplitude = 1.0f;
 106                 if(amplitude > gain)
 107                     gain = minf(gain+state->AttackRate, amplitude);
 108                 else if(amplitude < gain)
 109                     gain = maxf(gain-state->ReleaseRate, amplitude);
 110                 output = 1.0f / clampf(gain, 0.5f, 2.0f);
 111
 112                 temps[it] = smp * output;
 113             }
 114
 115             state->GainCtrl = gain;
 116         }
 117
 118
 119         for(kt = 0;kt < NumChannels;kt++)
 120         {
 121             ALfloat gain = state->Gain[kt];
 122             if(!(fabsf(gain) > GAIN_SILENCE_THRESHOLD))
 123                 continue;
 124
 125             for(it = 0;it < td;it++)
 126                 SamplesOut[kt][base+it] += gain * temps[it];
 127         }
 128
 129         base += td;
 130     }
 131 }
 132
 133 DECLARE_DEFAULT_ALLOCATORS(ALcompressorState)
 134
 135 DEFINE_ALEFFECTSTATE_VTABLE(ALcompressorState);
 136
 137
 138 typedef struct ALcompressorStateFactory {
 139     DERIVE_FROM_TYPE(ALeffectStateFactory);
 140 } ALcompressorStateFactory;
 141
 142 static ALeffectState *ALcompressorStateFactory_create(ALcompressorStateFactory *UNUSED(factory))
 143 {
 144     ALcompressorState *state;
 145
 146     state = ALcompressorState_New(sizeof(*state));
 147     if(!state) return NULL;
 148     SET_VTABLE2(ALcompressorState, ALeffectState, state);
 149
 150     state->Enabled = AL_TRUE;
 151     state->AttackRate = 0.0f;
 152     state->ReleaseRate = 0.0f;
 153     state->GainCtrl = 1.0f;
 154
 155     return STATIC_CAST(ALeffectState, state);
 156 }
 157
 158 DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALcompressorStateFactory);
 159
 160 ALeffectStateFactory *ALcompressorStateFactory_getFactory(void)
 161 {
 162     static ALcompressorStateFactory CompressorFactory = { { GET_VTABLE2(ALcompressorStateFactory, ALeffectStateFactory) } };
 163
 164     return STATIC_CAST(ALeffectStateFactory, &CompressorFactory);
 165 }
 166
 167
 168 void ALcompressor_setParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)
 169 {
 170     ALeffectProps *props = &effect->Props;
 171     switch(param)
 172     {
 173         case AL_COMPRESSOR_ONOFF:
 174             if(!(val >= AL_COMPRESSOR_MIN_ONOFF && val <= AL_COMPRESSOR_MAX_ONOFF))
 175                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 176             props->Compressor.OnOff = val;
 177             break;
 178
 179     default:
 180         SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 181     }
 182 }
 183 void ALcompressor_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
 184 {
 185     ALcompressor_setParami(effect, context, param, vals[0]);
 186 }
 187 void ALcompressor_setParamf(ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat UNUSED(val))
 188 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 189 void ALcompressor_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
 190 {
 191     ALcompressor_setParamf(effect, context, param, vals[0]);
 192 }
 193
 194 void ALcompressor_getParami(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)
 195 {
 196     const ALeffectProps *props = &effect->Props;
 197     switch(param)
 198     {
 199         case AL_COMPRESSOR_ONOFF:
 200             *val = props->Compressor.OnOff;
 201             break;
 202         default:
 203             SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 204     }
 205 }
 206 void ALcompressor_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
 207 {
 208     ALcompressor_getParami(effect, context, param, vals);
 209 }
 210 void ALcompressor_getParamf(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat *UNUSED(val))
 211 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 212 void ALcompressor_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
 213 {
 214     ALcompressor_getParamf(effect, context, param, vals);
 215 }
 216
 217 DEFINE_ALEFFECT_VTABLE(ALcompressor);