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, ALuint SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint 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     aluMatrixf matrix;
  82     ALuint i;
  83
  84     state->Enabled = props->Compressor.OnOff;
  85
  86     aluMatrixfSet(&matrix,
  87         1.0f, 0.0f, 0.0f, 0.0f,
  88         0.0f, 1.0f, 0.0f, 0.0f,
  89         0.0f, 0.0f, 1.0f, 0.0f,
  90         0.0f, 0.0f, 0.0f, 1.0f
  91     );
  92
  93     STATIC_CAST(ALeffectState,state)->OutBuffer = device->FOAOut.Buffer;
  94     STATIC_CAST(ALeffectState,state)->OutChannels = device->FOAOut.NumChannels;
  95     for(i = 0;i < 4;i++)
  96         ComputeFirstOrderGains(device->FOAOut, matrix.m[i], slot->Params.Gain,
  97                                state->Gain[i]);
  98 }
  99
 100 static ALvoid ALcompressorState_process(ALcompressorState *state, ALuint SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels)
 101 {
 102     ALuint i, j, k;
 103     ALuint base;
 104
 105     for(base = 0;base < SamplesToDo;)
 106     {
 107         ALfloat temps[64][4];
 108         ALuint td = minu(64, SamplesToDo-base);
 109
 110         /* Load samples into the temp buffer first. */
 111         for(j = 0;j < 4;j++)
 112         {
 113             for(i = 0;i < td;i++)
 114                 temps[i][j] = SamplesIn[j][i+base];
 115         }
 116
 117         if(state->Enabled)
 118         {
 119             ALfloat gain = state->GainCtrl;
 120             ALfloat output, amplitude;
 121
 122             for(i = 0;i < td;i++)
 123             {
 124                 /* Roughly calculate the maximum amplitude from the 4-channel
 125                  * signal, and attack or release the gain control to reach it.
 126                  */
 127                 amplitude = fabsf(temps[i][0]);
 128                 amplitude = maxf(amplitude + fabsf(temps[i][1]),
 129                                  maxf(amplitude + fabsf(temps[i][2]),
 130                                       amplitude + fabsf(temps[i][3])));
 131                 if(amplitude > gain)
 132                     gain = minf(gain+state->AttackRate, amplitude);
 133                 else if(amplitude < gain)
 134                     gain = maxf(gain-state->ReleaseRate, amplitude);
 135
 136                 /* Apply the inverse of the gain control to normalize/compress
 137                  * the volume. */
 138                 output = 1.0f / clampf(gain, 0.5f, 2.0f);
 139                 for(j = 0;j < 4;j++)
 140                     temps[i][j] *= output;
 141             }
 142
 143             state->GainCtrl = gain;
 144         }
 145         else
 146         {
 147             ALfloat gain = state->GainCtrl;
 148             ALfloat output, amplitude;
 149
 150             for(i = 0;i < td;i++)
 151             {
 152                 /* Same as above, except the amplitude is forced to 1. This
 153                  * helps ensure smooth gain changes when the compressor is
 154                  * turned on and off.
 155                  */
 156                 amplitude = 1.0f;
 157                 if(amplitude > gain)
 158                     gain = minf(gain+state->AttackRate, amplitude);
 159                 else if(amplitude < gain)
 160                     gain = maxf(gain-state->ReleaseRate, amplitude);
 161
 162                 output = 1.0f / clampf(gain, 0.5f, 2.0f);
 163                 for(j = 0;j < 4;j++)
 164                     temps[i][j] *= output;
 165             }
 166
 167             state->GainCtrl = gain;
 168         }
 169
 170         /* Now mix to the output. */
 171         for(j = 0;j < 4;j++)
 172         {
 173             for(k = 0;k < NumChannels;k++)
 174             {
 175                 ALfloat gain = state->Gain[j][k];
 176                 if(!(fabsf(gain) > GAIN_SILENCE_THRESHOLD))
 177                     continue;
 178
 179                 for(i = 0;i < td;i++)
 180                     SamplesOut[k][base+i] += gain * temps[i][j];
 181             }
 182         }
 183
 184         base += td;
 185     }
 186 }
 187
 188
 189 typedef struct ALcompressorStateFactory {
 190     DERIVE_FROM_TYPE(ALeffectStateFactory);
 191 } ALcompressorStateFactory;
 192
 193 static ALeffectState *ALcompressorStateFactory_create(ALcompressorStateFactory *UNUSED(factory))
 194 {
 195     ALcompressorState *state;
 196
 197     NEW_OBJ0(state, ALcompressorState)();
 198     if(!state) return NULL;
 199
 200     return STATIC_CAST(ALeffectState, state);
 201 }
 202
 203 DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALcompressorStateFactory);
 204
 205 ALeffectStateFactory *ALcompressorStateFactory_getFactory(void)
 206 {
 207     static ALcompressorStateFactory CompressorFactory = { { GET_VTABLE2(ALcompressorStateFactory, ALeffectStateFactory) } };
 208
 209     return STATIC_CAST(ALeffectStateFactory, &CompressorFactory);
 210 }
 211
 212
 213 void ALcompressor_setParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)
 214 {
 215     ALeffectProps *props = &effect->Props;
 216     switch(param)
 217     {
 218         case AL_COMPRESSOR_ONOFF:
 219             if(!(val >= AL_COMPRESSOR_MIN_ONOFF && val <= AL_COMPRESSOR_MAX_ONOFF))
 220                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 221             props->Compressor.OnOff = val;
 222             break;
 223
 224     default:
 225         SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 226     }
 227 }
 228 void ALcompressor_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
 229 {
 230     ALcompressor_setParami(effect, context, param, vals[0]);
 231 }
 232 void ALcompressor_setParamf(ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat UNUSED(val))
 233 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 234 void ALcompressor_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
 235 {
 236     ALcompressor_setParamf(effect, context, param, vals[0]);
 237 }
 238
 239 void ALcompressor_getParami(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)
 240 {
 241     const ALeffectProps *props = &effect->Props;
 242     switch(param)
 243     {
 244         case AL_COMPRESSOR_ONOFF:
 245             *val = props->Compressor.OnOff;
 246             break;
 247         default:
 248             SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 249     }
 250 }
 251 void ALcompressor_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
 252 {
 253     ALcompressor_getParami(effect, context, param, vals);
 254 }
 255 void ALcompressor_getParamf(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat *UNUSED(val))
 256 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 257 void ALcompressor_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
 258 {
 259     ALcompressor_getParamf(effect, context, param, vals);
 260 }
 261
 262 DEFINE_ALEFFECT_VTABLE(ALcompressor);