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_EFFECT_CHANNELS][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 *state);
  44 static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device);
  45 static ALvoid ALcompressorState_update(ALcompressorState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props);
  46 static ALvoid ALcompressorState_process(ALcompressorState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels);
  47 DECLARE_DEFAULT_ALLOCATORS(ALcompressorState)
  48
  49 DEFINE_ALEFFECTSTATE_VTABLE(ALcompressorState);
  50
  51
  52 static void ALcompressorState_Construct(ALcompressorState *state)
  53 {
  54     ALeffectState_Construct(STATIC_CAST(ALeffectState, state));
  55     SET_VTABLE2(ALcompressorState, ALeffectState, state);
  56
  57     state->Enabled = AL_TRUE;
  58     state->AttackRate = 0.0f;
  59     state->ReleaseRate = 0.0f;
  60     state->GainCtrl = 1.0f;
  61 }
  62
  63 static ALvoid ALcompressorState_Destruct(ALcompressorState *state)
  64 {
  65     ALeffectState_Destruct(STATIC_CAST(ALeffectState,state));
  66 }
  67
  68 static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device)
  69 {
  70     const ALfloat attackTime = device->Frequency * 0.2f; /* 200ms Attack */
  71     const ALfloat releaseTime = device->Frequency * 0.4f; /* 400ms Release */
  72
  73     state->AttackRate = 1.0f / attackTime;
  74     state->ReleaseRate = 1.0f / releaseTime;
  75
  76     return AL_TRUE;
  77 }
  78
  79 static ALvoid ALcompressorState_update(ALcompressorState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props)
  80 {
  81     const ALCdevice *device = context->Device;
  82     ALuint i;
  83
  84     state->Enabled = props->Compressor.OnOff;
  85
  86     STATIC_CAST(ALeffectState,state)->OutBuffer = device->FOAOut.Buffer;
  87     STATIC_CAST(ALeffectState,state)->OutChannels = device->FOAOut.NumChannels;
  88     for(i = 0;i < 4;i++)
  89         ComputeFirstOrderGains(&device->FOAOut, IdentityMatrixf.m[i],
  90                                slot->Params.Gain, state->Gain[i]);
  91 }
  92
  93 static ALvoid ALcompressorState_process(ALcompressorState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels)
  94 {
  95     ALsizei i, j, k;
  96     ALsizei base;
  97
  98     for(base = 0;base < SamplesToDo;)
  99     {
 100         ALfloat temps[64][4];
 101         ALsizei td = mini(64, SamplesToDo-base);
 102
 103         /* Load samples into the temp buffer first. */
 104         for(j = 0;j < 4;j++)
 105         {
 106             for(i = 0;i < td;i++)
 107                 temps[i][j] = SamplesIn[j][i+base];
 108         }
 109
 110         if(state->Enabled)
 111         {
 112             ALfloat gain = state->GainCtrl;
 113             ALfloat output, amplitude;
 114
 115             for(i = 0;i < td;i++)
 116             {
 117                 /* Roughly calculate the maximum amplitude from the 4-channel
 118                  * signal, and attack or release the gain control to reach it.
 119                  */
 120                 amplitude = fabsf(temps[i][0]);
 121                 amplitude = maxf(amplitude + fabsf(temps[i][1]),
 122                                  maxf(amplitude + fabsf(temps[i][2]),
 123                                       amplitude + fabsf(temps[i][3])));
 124                 if(amplitude > gain)
 125                     gain = minf(gain+state->AttackRate, amplitude);
 126                 else if(amplitude < gain)
 127                     gain = maxf(gain-state->ReleaseRate, amplitude);
 128
 129                 /* Apply the inverse of the gain control to normalize/compress
 130                  * the volume. */
 131                 output = 1.0f / clampf(gain, 0.5f, 2.0f);
 132                 for(j = 0;j < 4;j++)
 133                     temps[i][j] *= output;
 134             }
 135
 136             state->GainCtrl = gain;
 137         }
 138         else
 139         {
 140             ALfloat gain = state->GainCtrl;
 141             ALfloat output, amplitude;
 142
 143             for(i = 0;i < td;i++)
 144             {
 145                 /* Same as above, except the amplitude is forced to 1. This
 146                  * helps ensure smooth gain changes when the compressor is
 147                  * turned on and off.
 148                  */
 149                 amplitude = 1.0f;
 150                 if(amplitude > gain)
 151                     gain = minf(gain+state->AttackRate, amplitude);
 152                 else if(amplitude < gain)
 153                     gain = maxf(gain-state->ReleaseRate, amplitude);
 154
 155                 output = 1.0f / clampf(gain, 0.5f, 2.0f);
 156                 for(j = 0;j < 4;j++)
 157                     temps[i][j] *= output;
 158             }
 159
 160             state->GainCtrl = gain;
 161         }
 162
 163         /* Now mix to the output. */
 164         for(j = 0;j < 4;j++)
 165         {
 166             for(k = 0;k < NumChannels;k++)
 167             {
 168                 ALfloat gain = state->Gain[j][k];
 169                 if(!(fabsf(gain) > GAIN_SILENCE_THRESHOLD))
 170                     continue;
 171
 172                 for(i = 0;i < td;i++)
 173                     SamplesOut[k][base+i] += gain * temps[i][j];
 174             }
 175         }
 176
 177         base += td;
 178     }
 179 }
 180
 181
 182 typedef struct ALcompressorStateFactory {
 183     DERIVE_FROM_TYPE(ALeffectStateFactory);
 184 } ALcompressorStateFactory;
 185
 186 static ALeffectState *ALcompressorStateFactory_create(ALcompressorStateFactory *UNUSED(factory))
 187 {
 188     ALcompressorState *state;
 189
 190     NEW_OBJ0(state, ALcompressorState)();
 191     if(!state) return NULL;
 192
 193     return STATIC_CAST(ALeffectState, state);
 194 }
 195
 196 DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALcompressorStateFactory);
 197
 198 ALeffectStateFactory *ALcompressorStateFactory_getFactory(void)
 199 {
 200     static ALcompressorStateFactory CompressorFactory = { { GET_VTABLE2(ALcompressorStateFactory, ALeffectStateFactory) } };
 201
 202     return STATIC_CAST(ALeffectStateFactory, &CompressorFactory);
 203 }
 204
 205
 206 void ALcompressor_setParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)
 207 {
 208     ALeffectProps *props = &effect->Props;
 209     switch(param)
 210     {
 211         case AL_COMPRESSOR_ONOFF:
 212             if(!(val >= AL_COMPRESSOR_MIN_ONOFF && val <= AL_COMPRESSOR_MAX_ONOFF))
 213                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 214             props->Compressor.OnOff = val;
 215             break;
 216
 217     default:
 218         SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 219     }
 220 }
 221 void ALcompressor_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
 222 {
 223     ALcompressor_setParami(effect, context, param, vals[0]);
 224 }
 225 void ALcompressor_setParamf(ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat UNUSED(val))
 226 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 227 void ALcompressor_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
 228 {
 229     ALcompressor_setParamf(effect, context, param, vals[0]);
 230 }
 231
 232 void ALcompressor_getParami(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)
 233 {
 234     const ALeffectProps *props = &effect->Props;
 235     switch(param)
 236     {
 237         case AL_COMPRESSOR_ONOFF:
 238             *val = props->Compressor.OnOff;
 239             break;
 240         default:
 241             SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 242     }
 243 }
 244 void ALcompressor_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
 245 {
 246     ALcompressor_getParami(effect, context, param, vals);
 247 }
 248 void ALcompressor_getParamf(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat *UNUSED(val))
 249 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 250 void ALcompressor_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
 251 {
 252     ALcompressor_getParamf(effect, context, param, vals);
 253 }
 254
 255 DEFINE_ALEFFECT_VTABLE(ALcompressor);