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