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 "alAuxEffectSlot.h"
  28 #include "alError.h"
  29 #include "alu.h"
  30 #include "filters/defs.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
  75 typedef struct ALequalizerState {
  76     DERIVE_FROM_TYPE(ALeffectState);
  77
  78     struct {
  79         /* Effect gains for each channel */
  80         ALfloat CurrentGains[MAX_OUTPUT_CHANNELS];
  81         ALfloat TargetGains[MAX_OUTPUT_CHANNELS];
  82
  83         /* Effect parameters */
  84         BiquadState filter[4];
  85     } Chans[MAX_EFFECT_CHANNELS];
  86
  87     ALfloat SampleBuffer[MAX_EFFECT_CHANNELS][BUFFERSIZE];
  88 } ALequalizerState;
  89
  90 static ALvoid ALequalizerState_Destruct(ALequalizerState *state);
  91 static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *state, ALCdevice *device);
  92 static ALvoid ALequalizerState_update(ALequalizerState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props);
  93 static ALvoid ALequalizerState_process(ALequalizerState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels);
  94 DECLARE_DEFAULT_ALLOCATORS(ALequalizerState)
  95
  96 DEFINE_ALEFFECTSTATE_VTABLE(ALequalizerState);
  97
  98
  99 static void ALequalizerState_Construct(ALequalizerState *state)
 100 {
 101     ALeffectState_Construct(STATIC_CAST(ALeffectState, state));
 102     SET_VTABLE2(ALequalizerState, ALeffectState, state);
 103 }
 104
 105 static ALvoid ALequalizerState_Destruct(ALequalizerState *state)
 106 {
 107     ALeffectState_Destruct(STATIC_CAST(ALeffectState,state));
 108 }
 109
 110 static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *state, ALCdevice *UNUSED(device))
 111 {
 112     ALsizei i, j;
 113
 114     for(i = 0; i < MAX_EFFECT_CHANNELS;i++)
 115     {
 116         for(j = 0;j < 4;j++)
 117             BiquadState_clear(&state->Chans[i].filter[j]);
 118         for(j = 0;j < MAX_OUTPUT_CHANNELS;j++)
 119             state->Chans[i].CurrentGains[j] = 0.0f;
 120     }
 121     return AL_TRUE;
 122 }
 123
 124 static ALvoid ALequalizerState_update(ALequalizerState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props)
 125 {
 126     const ALCdevice *device = context->Device;
 127     ALfloat frequency = (ALfloat)device->Frequency;
 128     ALfloat gain, f0norm;
 129     ALuint i;
 130
 131     STATIC_CAST(ALeffectState,state)->OutBuffer = device->FOAOut.Buffer;
 132     STATIC_CAST(ALeffectState,state)->OutChannels = device->FOAOut.NumChannels;
 133     for(i = 0;i < MAX_EFFECT_CHANNELS;i++)
 134         ComputeFirstOrderGains(&device->FOAOut, IdentityMatrixf.m[i],
 135                                slot->Params.Gain, state->Chans[i].TargetGains);
 136
 137     /* Calculate coefficients for the each type of filter. Note that the shelf
 138      * filters' gain is for the reference frequency, which is the centerpoint
 139      * of the transition band.
 140      */
 141     gain = maxf(sqrtf(props->Equalizer.LowGain), 0.0625f); /* Limit -24dB */
 142     f0norm = props->Equalizer.LowCutoff/frequency;
 143     BiquadState_setParams(&state->Chans[0].filter[0], BiquadType_LowShelf,
 144         gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f)
 145     );
 146
 147     gain = maxf(props->Equalizer.Mid1Gain, 0.0625f);
 148     f0norm = props->Equalizer.Mid1Center/frequency;
 149     BiquadState_setParams(&state->Chans[0].filter[1], BiquadType_Peaking,
 150         gain, f0norm, calc_rcpQ_from_bandwidth(
 151             f0norm, props->Equalizer.Mid1Width
 152         )
 153     );
 154
 155     gain = maxf(props->Equalizer.Mid2Gain, 0.0625f);
 156     f0norm = props->Equalizer.Mid2Center/frequency;
 157     BiquadState_setParams(&state->Chans[0].filter[2], BiquadType_Peaking,
 158         gain, f0norm, calc_rcpQ_from_bandwidth(
 159             f0norm, props->Equalizer.Mid2Width
 160         )
 161     );
 162
 163     gain = maxf(sqrtf(props->Equalizer.HighGain), 0.0625f);
 164     f0norm = props->Equalizer.HighCutoff/frequency;
 165     BiquadState_setParams(&state->Chans[0].filter[3], BiquadType_HighShelf,
 166         gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f)
 167     );
 168
 169     /* Copy the filter coefficients for the other input channels. */
 170     for(i = 1;i < MAX_EFFECT_CHANNELS;i++)
 171     {
 172         BiquadState_copyParams(&state->Chans[i].filter[0], &state->Chans[0].filter[0]);
 173         BiquadState_copyParams(&state->Chans[i].filter[1], &state->Chans[0].filter[1]);
 174         BiquadState_copyParams(&state->Chans[i].filter[2], &state->Chans[0].filter[2]);
 175         BiquadState_copyParams(&state->Chans[i].filter[3], &state->Chans[0].filter[3]);
 176     }
 177 }
 178
 179 static ALvoid ALequalizerState_process(ALequalizerState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels)
 180 {
 181     ALfloat (*restrict temps)[BUFFERSIZE] = state->SampleBuffer;
 182     ALsizei c;
 183
 184     for(c = 0;c < MAX_EFFECT_CHANNELS;c++)
 185     {
 186         BiquadState_process(&state->Chans[c].filter[0], temps[0], SamplesIn[c], SamplesToDo);
 187         BiquadState_process(&state->Chans[c].filter[1], temps[1], temps[0], SamplesToDo);
 188         BiquadState_process(&state->Chans[c].filter[2], temps[2], temps[1], SamplesToDo);
 189         BiquadState_process(&state->Chans[c].filter[3], temps[3], temps[2], SamplesToDo);
 190
 191         MixSamples(temps[3], NumChannels, SamplesOut,
 192             state->Chans[c].CurrentGains, state->Chans[c].TargetGains,
 193             SamplesToDo, 0, SamplesToDo
 194         );
 195     }
 196 }
 197
 198
 199 typedef struct EqualizerStateFactory {
 200     DERIVE_FROM_TYPE(EffectStateFactory);
 201 } EqualizerStateFactory;
 202
 203 ALeffectState *EqualizerStateFactory_create(EqualizerStateFactory *UNUSED(factory))
 204 {
 205     ALequalizerState *state;
 206
 207     NEW_OBJ0(state, ALequalizerState)();
 208     if(!state) return NULL;
 209
 210     return STATIC_CAST(ALeffectState, state);
 211 }
 212
 213 DEFINE_EFFECTSTATEFACTORY_VTABLE(EqualizerStateFactory);
 214
 215 EffectStateFactory *EqualizerStateFactory_getFactory(void)
 216 {
 217     static EqualizerStateFactory EqualizerFactory = { { GET_VTABLE2(EqualizerStateFactory, EffectStateFactory) } };
 218
 219     return STATIC_CAST(EffectStateFactory, &EqualizerFactory);
 220 }
 221
 222
 223 void ALequalizer_setParami(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint UNUSED(val))
 224 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); }
 225 void ALequalizer_setParamiv(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, const ALint *UNUSED(vals))
 226 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); }
 227 void ALequalizer_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
 228 {
 229     ALeffectProps *props = &effect->Props;
 230     switch(param)
 231     {
 232         case AL_EQUALIZER_LOW_GAIN:
 233             if(!(val >= AL_EQUALIZER_MIN_LOW_GAIN && val <= AL_EQUALIZER_MAX_LOW_GAIN))
 234                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band gain out of range");
 235             props->Equalizer.LowGain = val;
 236             break;
 237
 238         case AL_EQUALIZER_LOW_CUTOFF:
 239             if(!(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF))
 240                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band cutoff out of range");
 241             props->Equalizer.LowCutoff = val;
 242             break;
 243
 244         case AL_EQUALIZER_MID1_GAIN:
 245             if(!(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN))
 246                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band gain out of range");
 247             props->Equalizer.Mid1Gain = val;
 248             break;
 249
 250         case AL_EQUALIZER_MID1_CENTER:
 251             if(!(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER))
 252                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band center out of range");
 253             props->Equalizer.Mid1Center = val;
 254             break;
 255
 256         case AL_EQUALIZER_MID1_WIDTH:
 257             if(!(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH))
 258                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band width out of range");
 259             props->Equalizer.Mid1Width = val;
 260             break;
 261
 262         case AL_EQUALIZER_MID2_GAIN:
 263             if(!(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN))
 264                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band gain out of range");
 265             props->Equalizer.Mid2Gain = val;
 266             break;
 267
 268         case AL_EQUALIZER_MID2_CENTER:
 269             if(!(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER))
 270                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band center out of range");
 271             props->Equalizer.Mid2Center = val;
 272             break;
 273
 274         case AL_EQUALIZER_MID2_WIDTH:
 275             if(!(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH))
 276                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band width out of range");
 277             props->Equalizer.Mid2Width = val;
 278             break;
 279
 280         case AL_EQUALIZER_HIGH_GAIN:
 281             if(!(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN))
 282                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band gain out of range");
 283             props->Equalizer.HighGain = val;
 284             break;
 285
 286         case AL_EQUALIZER_HIGH_CUTOFF:
 287             if(!(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF))
 288                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band cutoff out of range");
 289             props->Equalizer.HighCutoff = val;
 290             break;
 291
 292         default:
 293             alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param);
 294     }
 295 }
 296 void ALequalizer_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
 297 { ALequalizer_setParamf(effect, context, param, vals[0]); }
 298
 299 void ALequalizer_getParami(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint *UNUSED(val))
 300 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); }
 301 void ALequalizer_getParamiv(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint *UNUSED(vals))
 302 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); }
 303 void ALequalizer_getParamf(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
 304 {
 305     const ALeffectProps *props = &effect->Props;
 306     switch(param)
 307     {
 308         case AL_EQUALIZER_LOW_GAIN:
 309             *val = props->Equalizer.LowGain;
 310             break;
 311
 312         case AL_EQUALIZER_LOW_CUTOFF:
 313             *val = props->Equalizer.LowCutoff;
 314             break;
 315
 316         case AL_EQUALIZER_MID1_GAIN:
 317             *val = props->Equalizer.Mid1Gain;
 318             break;
 319
 320         case AL_EQUALIZER_MID1_CENTER:
 321             *val = props->Equalizer.Mid1Center;
 322             break;
 323
 324         case AL_EQUALIZER_MID1_WIDTH:
 325             *val = props->Equalizer.Mid1Width;
 326             break;
 327
 328         case AL_EQUALIZER_MID2_GAIN:
 329             *val = props->Equalizer.Mid2Gain;
 330             break;
 331
 332         case AL_EQUALIZER_MID2_CENTER:
 333             *val = props->Equalizer.Mid2Center;
 334             break;
 335
 336         case AL_EQUALIZER_MID2_WIDTH:
 337             *val = props->Equalizer.Mid2Width;
 338             break;
 339
 340         case AL_EQUALIZER_HIGH_GAIN:
 341             *val = props->Equalizer.HighGain;
 342             break;
 343
 344         case AL_EQUALIZER_HIGH_CUTOFF:
 345             *val = props->Equalizer.HighCutoff;
 346             break;
 347
 348         default:
 349             alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param);
 350     }
 351 }
 352 void ALequalizer_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
 353 { ALequalizer_getParamf(effect, context, param, vals); }
 354
 355 DEFINE_ALEFFECT_VTABLE(ALequalizer);