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[MAX_OUTPUT_CHANNELS];
  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
  97     ComputeAmbientGains(device, slot->Gain, state->Gain);
  98
  99     /* Calculate coefficients for the each type of filter */
 100     ALfilterState_setParams(&state->filter[0], ALfilterType_LowShelf,
 101                             sqrtf(slot->EffectProps.Equalizer.LowGain),
 102                             slot->EffectProps.Equalizer.LowCutoff/frequency,
 103                             0.0f);
 104
 105     ALfilterState_setParams(&state->filter[1], ALfilterType_Peaking,
 106                             sqrtf(slot->EffectProps.Equalizer.Mid1Gain),
 107                             slot->EffectProps.Equalizer.Mid1Center/frequency,
 108                             slot->EffectProps.Equalizer.Mid1Width);
 109
 110     ALfilterState_setParams(&state->filter[2], ALfilterType_Peaking,
 111                             sqrtf(slot->EffectProps.Equalizer.Mid2Gain),
 112                             slot->EffectProps.Equalizer.Mid2Center/frequency,
 113                             slot->EffectProps.Equalizer.Mid2Width);
 114
 115     ALfilterState_setParams(&state->filter[3], ALfilterType_HighShelf,
 116                             sqrtf(slot->EffectProps.Equalizer.HighGain),
 117                             slot->EffectProps.Equalizer.HighCutoff/frequency,
 118                             0.0f);
 119 }
 120
 121 static ALvoid ALequalizerState_process(ALequalizerState *state, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels)
 122 {
 123     ALuint base;
 124     ALuint it;
 125     ALuint kt;
 126     ALuint ft;
 127
 128     for(base = 0;base < SamplesToDo;)
 129     {
 130         ALfloat temps[64];
 131         ALuint td = minu(SamplesToDo-base, 64);
 132
 133         for(it = 0;it < td;it++)
 134         {
 135             ALfloat smp = SamplesIn[base+it];
 136
 137             for(ft = 0;ft < 4;ft++)
 138                 smp = ALfilterState_processSingle(&state->filter[ft], smp);
 139
 140             temps[it] = smp;
 141         }
 142
 143         for(kt = 0;kt < NumChannels;kt++)
 144         {
 145             ALfloat gain = state->Gain[kt];
 146             if(!(fabsf(gain) > GAIN_SILENCE_THRESHOLD))
 147                 continue;
 148
 149             for(it = 0;it < td;it++)
 150                 SamplesOut[kt][base+it] += gain * temps[it];
 151         }
 152
 153         base += td;
 154     }
 155 }
 156
 157 DECLARE_DEFAULT_ALLOCATORS(ALequalizerState)
 158
 159 DEFINE_ALEFFECTSTATE_VTABLE(ALequalizerState);
 160
 161
 162 typedef struct ALequalizerStateFactory {
 163     DERIVE_FROM_TYPE(ALeffectStateFactory);
 164 } ALequalizerStateFactory;
 165
 166 ALeffectState *ALequalizerStateFactory_create(ALequalizerStateFactory *UNUSED(factory))
 167 {
 168     ALequalizerState *state;
 169     int it;
 170
 171     state = ALequalizerState_New(sizeof(*state));
 172     if(!state) return NULL;
 173     SET_VTABLE2(ALequalizerState, ALeffectState, state);
 174
 175     /* Initialize sample history only on filter creation to avoid */
 176     /* sound clicks if filter settings were changed in runtime.   */
 177     for(it = 0; it < 4; it++)
 178         ALfilterState_clear(&state->filter[it]);
 179
 180     return STATIC_CAST(ALeffectState, state);
 181 }
 182
 183 DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALequalizerStateFactory);
 184
 185 ALeffectStateFactory *ALequalizerStateFactory_getFactory(void)
 186 {
 187     static ALequalizerStateFactory EqualizerFactory = { { GET_VTABLE2(ALequalizerStateFactory, ALeffectStateFactory) } };
 188
 189     return STATIC_CAST(ALeffectStateFactory, &EqualizerFactory);
 190 }
 191
 192
 193 void ALequalizer_setParami(ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALint UNUSED(val))
 194 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 195 void ALequalizer_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
 196 {
 197     ALequalizer_setParami(effect, context, param, vals[0]);
 198 }
 199 void ALequalizer_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
 200 {
 201     ALeffectProps *props = &effect->Props;
 202     switch(param)
 203     {
 204         case AL_EQUALIZER_LOW_GAIN:
 205             if(!(val >= AL_EQUALIZER_MIN_LOW_GAIN && val <= AL_EQUALIZER_MAX_LOW_GAIN))
 206                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 207             props->Equalizer.LowGain = val;
 208             break;
 209
 210         case AL_EQUALIZER_LOW_CUTOFF:
 211             if(!(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF))
 212                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 213             props->Equalizer.LowCutoff = val;
 214             break;
 215
 216         case AL_EQUALIZER_MID1_GAIN:
 217             if(!(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN))
 218                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 219             props->Equalizer.Mid1Gain = val;
 220             break;
 221
 222         case AL_EQUALIZER_MID1_CENTER:
 223             if(!(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER))
 224                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 225             props->Equalizer.Mid1Center = val;
 226             break;
 227
 228         case AL_EQUALIZER_MID1_WIDTH:
 229             if(!(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH))
 230                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 231             props->Equalizer.Mid1Width = val;
 232             break;
 233
 234         case AL_EQUALIZER_MID2_GAIN:
 235             if(!(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN))
 236                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 237             props->Equalizer.Mid2Gain = val;
 238             break;
 239
 240         case AL_EQUALIZER_MID2_CENTER:
 241             if(!(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER))
 242                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 243             props->Equalizer.Mid2Center = val;
 244             break;
 245
 246         case AL_EQUALIZER_MID2_WIDTH:
 247             if(!(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH))
 248                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 249             props->Equalizer.Mid2Width = val;
 250             break;
 251
 252         case AL_EQUALIZER_HIGH_GAIN:
 253             if(!(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN))
 254                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 255             props->Equalizer.HighGain = val;
 256             break;
 257
 258         case AL_EQUALIZER_HIGH_CUTOFF:
 259             if(!(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF))
 260                 SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
 261             props->Equalizer.HighCutoff = val;
 262             break;
 263
 264         default:
 265             SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 266     }
 267 }
 268 void ALequalizer_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
 269 {
 270     ALequalizer_setParamf(effect, context, param, vals[0]);
 271 }
 272
 273 void ALequalizer_getParami(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALint *UNUSED(val))
 274 { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
 275 void ALequalizer_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
 276 {
 277     ALequalizer_getParami(effect, context, param, vals);
 278 }
 279 void ALequalizer_getParamf(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
 280 {
 281     const ALeffectProps *props = &effect->Props;
 282     switch(param)
 283     {
 284         case AL_EQUALIZER_LOW_GAIN:
 285             *val = props->Equalizer.LowGain;
 286             break;
 287
 288         case AL_EQUALIZER_LOW_CUTOFF:
 289             *val = props->Equalizer.LowCutoff;
 290             break;
 291
 292         case AL_EQUALIZER_MID1_GAIN:
 293             *val = props->Equalizer.Mid1Gain;
 294             break;
 295
 296         case AL_EQUALIZER_MID1_CENTER:
 297             *val = props->Equalizer.Mid1Center;
 298             break;
 299
 300         case AL_EQUALIZER_MID1_WIDTH:
 301             *val = props->Equalizer.Mid1Width;
 302             break;
 303
 304         case AL_EQUALIZER_MID2_GAIN:
 305             *val = props->Equalizer.Mid2Gain;
 306             break;
 307
 308         case AL_EQUALIZER_MID2_CENTER:
 309             *val = props->Equalizer.Mid2Center;
 310             break;
 311
 312         case AL_EQUALIZER_MID2_WIDTH:
 313             *val = props->Equalizer.Mid2Width;
 314             break;
 315
 316         case AL_EQUALIZER_HIGH_GAIN:
 317             *val = props->Equalizer.HighGain;
 318             break;
 319
 320         case AL_EQUALIZER_HIGH_CUTOFF:
 321             *val = props->Equalizer.HighCutoff;
 322             break;
 323
 324         default:
 325             SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
 326     }
 327 }
 328 void ALequalizer_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
 329 {
 330     ALequalizer_getParamf(effect, context, param, vals);
 331 }
 332
 333 DEFINE_ALEFFECT_VTABLE(ALequalizer);