Alc/effects/equalizer.c

   1 /**
   2  * OpenAL cross platform audio library
   3  * Copyright (C) 2013 by Mike Gorchak
   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 "config.h"
  22
  23 #include <math.h>
  24 #include <stdlib.h>
  25
  26 #include "alMain.h"
  27 #include "alFilter.h"
  28 #include "alAuxEffectSlot.h"
  29 #include "alError.h"
  30 #include "alu.h"
  31
  32
  33 /*  The document  "Effects Extension Guide.pdf"  says that low and high  *
  34  *  frequencies are cutoff frequencies. This is not fully correct, they  *
  35  *  are corner frequencies for low and high shelf filters. If they were  *
  36  *  just cutoff frequencies, there would be no need in cutoff frequency  *
  37  *  gains, which are present.  Documentation for  "Creative Proteus X2"  *
  38  *  software describes  4-band equalizer functionality in a much better  *
  39  *  way.  This equalizer seems  to be a predecessor  of  OpenAL  4-band  *
  40  *  equalizer.  With low and high  shelf filters  we are able to cutoff  *
  41  *  frequencies below and/or above corner frequencies using attenuation  *
  42  *  gains (below 1.0) and amplify all low and/or high frequencies using  *
  43  *  gains above 1.0.                                                     *
  44  *                                                                       *
  45  *     Low-shelf       Low Mid Band      High Mid Band     High-shelf    *
  46  *      corner            center             center          corner      *
  47  *     frequency        frequency          frequency       frequency     *
  48  *    50Hz..800Hz     200Hz..3000Hz      1000Hz..8000Hz  4000Hz..16000Hz *
  49  *                                                                       *
  50  *          |               |                  |               |         *
  51  *          |               |                  |               |         *
  52  *   B -----+            /--+--\            /--+--\            +-----    *
  53  *   O      |\          |   |   |          |   |   |          /|         *
  54  *   O      | \        -    |    -        -    |    -        / |         *
  55  *   S +    |  \      |     |     |      |     |     |      /  |         *
  56  *   T      |   |    |      |      |    |      |      |    |   |         *
  57  * ---------+---------------+------------------+---------------+-------- *
  58  *   C      |   |    |      |      |    |      |      |    |   |         *
  59  *   U -    |  /      |     |     |      |     |     |      \  |         *
  60  *   T      | /        -    |    -        -    |    -        \ |         *
  61  *   O      |/          |   |   |          |   |   |          \|         *
  62  *   F -----+            \--+--/            \--+--/            +-----    *
  63  *   F      |               |                  |               |         *
  64  *          |               |                  |               |         *
  65  *                                                                       *
  66  * Gains vary from 0.126 up to 7.943, which means from -18dB attenuation *
  67  * up to +18dB amplification. Band width varies from 0.01 up to 1.0 in   *
  68  * octaves for two mid bands.                                            *
  69  *                                                                       *
  70  * Implementation is based on the "Cookbook formulae for audio EQ biquad *
  71  * filter coefficients" by Robert Bristow-Johnson                        *
  72  * http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt                   */
  73
  74 typedef struct ALequalizerState {
  75     DERIVE_FROM_TYPE(ALeffectState);
  76
  77     /* Effect gains for each channel */
  78     ALfloat Gain[MaxChannels];
  79
  80     /* Effect parameters */
  81     ALfilterState filter[4];
  82 } ALequalizerState;
  83
  84 static ALvoid ALequalizerState_Destruct(ALequalizerState *UNUSED(state))
  85 {
  86 }
  87
  88 static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *UNUSED(state), ALCdevice *UNUSED(device))
  89 {
  90     return AL_TRUE;
  91 }
  92
  93 static ALvoid ALequalizerState_update(ALequalizerState *state, ALCdevice *device, const ALeffectslot *slot)
  94 {
  95     ALfloat frequency = (ALfloat)device->Frequency;
  96     ALfloat gain = 1.0f/device->NumSpeakers * slot->Gain;
  97
  98     SetGains(device, gain, state->Gain);
  99
 100     /* Calculate coefficients for the each type of filter */
 101     ALfilterState_setParams(&state->filter[0], ALfilterType_LowShelf,
 102                             sqrtf(slot->EffectProps.Equalizer.LowGain),
 103                             slot->EffectProps.Equalizer.LowCutoff/frequency,
 104                             0.0f);
 105
 106     ALfilterState_setParams(&state->filter[1], ALfilterType_Peaking,
 107                             sqrtf(slot->EffectProps.Equalizer.Mid1Gain),
 108                             slot->EffectProps.Equalizer.Mid1Center/frequency,
 109                             slot->EffectProps.Equalizer.Mid1Width);
 110
 111     ALfilterState_setParams(&state->filter[2], ALfilterType_Peaking,
 112                             sqrtf(slot->EffectProps.Equalizer.Mid2Gain),
 113                             slot->EffectProps.Equalizer.Mid2Center/frequency,
 114                             slot->EffectProps.Equalizer.Mid2Width);
 115
 116     ALfilterState_setParams(&state->filter[3], ALfilterType_HighShelf,
 117                             sqrtf(slot->EffectProps.Equalizer.HighGain),
 118                             slot->EffectProps.Equalizer.HighCutoff/frequency,
 119                             0.0f);
 120 }
 121
 122 static ALvoid ALequalizerState_process(ALequalizerState *state, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE])
 123 {
 124     ALuint base;
 125     ALuint it;
 126     ALuint kt;
 127     ALuint ft;
 128
 129     for(base = 0;base < SamplesToDo;)
 130     {
 131         ALfloat temps[64];
 132         ALuint td = minu(SamplesToDo-base, 64);
 133
 134         for(it = 0;it < td;it++)
 135         {
 136             ALfloat smp = SamplesIn[base+it];
 137
 138             for(ft = 0;ft < 4;ft++)
 139                 smp = ALfilterState_processSingle(&state->filter[ft], smp);
 140
 141             temps[it] = smp;
 142         }
 143
 144         for(kt = 0;kt < MaxChannels;kt++)
 145         {
 146             ALfloat gain = state->Gain[kt];
 147             if(!(gain > GAIN_SILENCE_THRESHOLD))
 148                 continue;
 149
 150             for(it = 0;it < td;it++)
 151                 SamplesOut[kt][base+it] += gain * temps[it];
 152         }
 153
 154         base += td;
 155     }
 156 }
 157
 158 DECLARE_DEFAULT_ALLOCATORS(ALequalizerState)
 159
 160 DEFINE_ALEFFECTSTATE_VTABLE(ALequalizerState);
 161
 162
 163 typedef struct ALequalizerStateFactory {
 164     DERIVE_FROM_TYPE(ALeffectStateFactory);
 165 } ALequalizerStateFactory;
 166
 167 ALeffectState *ALequalizerStateFactory_create(ALequalizerStateFactory *UNUSED(factory))
 168 {
 169     ALequalizerState *state;
 170     int it;
 171
 172     state = ALequalizerState_New(sizeof(*state));
 173     if(!state) return NULL;
 174     SET_VTABLE2(ALequalizerState, ALeffectState, state);
 175
 176     /* Initialize sample history only on filter creation to avoid */
 177     /* sound clicks if filter settings were changed in runtime.   */
 178     for(it = 0; it < 4; it++)
 179         ALfilterState_clear(&state->filter[it]);
 180
 181     return STATIC_CAST(ALeffectState, state);
 182 }
 183
 184 DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALequalizerStateFactory);
 185
 186 ALeffectStateFactory *ALequalizerStateFactory_getFactory(void)
 187 {
 188     static ALequalizerStateFactory EqualizerFactory = { { GET_VTABLE2(ALequalizerStateFactory, ALeffectStateFactory) } };
 189
 190     return STATIC_CAST(ALeffectStateFactory, &EqualizerFactory);
 191 }
 192
 193
 194 void ALequalizer_setParami(ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALint UNUSED(val))
 195 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 196 void ALequalizer_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
 197 {
 198     ALequalizer_setParami(effect, context, param, vals[0]);
 199 }
 200 void ALequalizer_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
 201 {
 202     ALeffectProps *props = &effect->Props;
 203     switch(param)
 204     {
 205         case AL_EQUALIZER_LOW_GAIN:
 206             if(!(val >= AL_EQUALIZER_MIN_LOW_GAIN && val <= AL_EQUALIZER_MAX_LOW_GAIN))
 207                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 208             props->Equalizer.LowGain = val;
 209             break;
 210
 211         case AL_EQUALIZER_LOW_CUTOFF:
 212             if(!(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF))
 213                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 214             props->Equalizer.LowCutoff = val;
 215             break;
 216
 217         case AL_EQUALIZER_MID1_GAIN:
 218             if(!(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN))
 219                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 220             props->Equalizer.Mid1Gain = val;
 221             break;
 222
 223         case AL_EQUALIZER_MID1_CENTER:
 224             if(!(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER))
 225                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 226             props->Equalizer.Mid1Center = val;
 227             break;
 228
 229         case AL_EQUALIZER_MID1_WIDTH:
 230             if(!(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH))
 231                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 232             props->Equalizer.Mid1Width = val;
 233             break;
 234
 235         case AL_EQUALIZER_MID2_GAIN:
 236             if(!(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN))
 237                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 238             props->Equalizer.Mid2Gain = val;
 239             break;
 240
 241         case AL_EQUALIZER_MID2_CENTER:
 242             if(!(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER))
 243                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 244             props->Equalizer.Mid2Center = val;
 245             break;
 246
 247         case AL_EQUALIZER_MID2_WIDTH:
 248             if(!(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH))
 249                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 250             props->Equalizer.Mid2Width = val;
 251             break;
 252
 253         case AL_EQUALIZER_HIGH_GAIN:
 254             if(!(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN))
 255                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 256             props->Equalizer.HighGain = val;
 257             break;
 258
 259         case AL_EQUALIZER_HIGH_CUTOFF:
 260             if(!(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF))
 261                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 262             props->Equalizer.HighCutoff = val;
 263             break;
 264
 265         default:
 266             SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 267     }
 268 }
 269 void ALequalizer_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
 270 {
 271     ALequalizer_setParamf(effect, context, param, vals[0]);
 272 }
 273
 274 void ALequalizer_getParami(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALint *UNUSED(val))
 275 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 276 void ALequalizer_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
 277 {
 278     ALequalizer_getParami(effect, context, param, vals);
 279 }
 280 void ALequalizer_getParamf(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
 281 {
 282     const ALeffectProps *props = &effect->Props;
 283     switch(param)
 284     {
 285         case AL_EQUALIZER_LOW_GAIN:
 286             *val = props->Equalizer.LowGain;
 287             break;
 288
 289         case AL_EQUALIZER_LOW_CUTOFF:
 290             *val = props->Equalizer.LowCutoff;
 291             break;
 292
 293         case AL_EQUALIZER_MID1_GAIN:
 294             *val = props->Equalizer.Mid1Gain;
 295             break;
 296
 297         case AL_EQUALIZER_MID1_CENTER:
 298             *val = props->Equalizer.Mid1Center;
 299             break;
 300
 301         case AL_EQUALIZER_MID1_WIDTH:
 302             *val = props->Equalizer.Mid1Width;
 303             break;
 304
 305         case AL_EQUALIZER_MID2_GAIN:
 306             *val = props->Equalizer.Mid2Gain;
 307             break;
 308
 309         case AL_EQUALIZER_MID2_CENTER:
 310             *val = props->Equalizer.Mid2Center;
 311             break;
 312
 313         case AL_EQUALIZER_MID2_WIDTH:
 314             *val = props->Equalizer.Mid2Width;
 315             break;
 316
 317         case AL_EQUALIZER_HIGH_GAIN:
 318             *val = props->Equalizer.HighGain;
 319             break;
 320
 321         case AL_EQUALIZER_HIGH_CUTOFF:
 322             *val = props->Equalizer.HighCutoff;
 323             break;
 324
 325         default:
 326             SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 327     }
 328 }
 329 void ALequalizer_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
 330 {
 331     ALequalizer_getParamf(effect, context, param, vals);
 332 }
 333
 334 DEFINE_ALEFFECT_VTABLE(ALequalizer);