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