Alc/effects/equalizer.cpp

   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 "alcontext.h"
  28 #include "alAuxEffectSlot.h"
  29 #include "alError.h"
  30 #include "alu.h"
  31 #include "filters/defs.h"
  32 #include "vecmat.h"
  33
  34
  35 /*  The document  "Effects Extension Guide.pdf"  says that low and high  *
  36  *  frequencies are cutoff frequencies. This is not fully correct, they  *
  37  *  are corner frequencies for low and high shelf filters. If they were  *
  38  *  just cutoff frequencies, there would be no need in cutoff frequency  *
  39  *  gains, which are present.  Documentation for  "Creative Proteus X2"  *
  40  *  software describes  4-band equalizer functionality in a much better  *
  41  *  way.  This equalizer seems  to be a predecessor  of  OpenAL  4-band  *
  42  *  equalizer.  With low and high  shelf filters  we are able to cutoff  *
  43  *  frequencies below and/or above corner frequencies using attenuation  *
  44  *  gains (below 1.0) and amplify all low and/or high frequencies using  *
  45  *  gains above 1.0.                                                     *
  46  *                                                                       *
  47  *     Low-shelf       Low Mid Band      High Mid Band     High-shelf    *
  48  *      corner            center             center          corner      *
  49  *     frequency        frequency          frequency       frequency     *
  50  *    50Hz..800Hz     200Hz..3000Hz      1000Hz..8000Hz  4000Hz..16000Hz *
  51  *                                                                       *
  52  *          |               |                  |               |         *
  53  *          |               |                  |               |         *
  54  *   B -----+            /--+--\            /--+--\            +-----    *
  55  *   O      |\          |   |   |          |   |   |          /|         *
  56  *   O      | \        -    |    -        -    |    -        / |         *
  57  *   S +    |  \      |     |     |      |     |     |      /  |         *
  58  *   T      |   |    |      |      |    |      |      |    |   |         *
  59  * ---------+---------------+------------------+---------------+-------- *
  60  *   C      |   |    |      |      |    |      |      |    |   |         *
  61  *   U -    |  /      |     |     |      |     |     |      \  |         *
  62  *   T      | /        -    |    -        -    |    -        \ |         *
  63  *   O      |/          |   |   |          |   |   |          \|         *
  64  *   F -----+            \--+--/            \--+--/            +-----    *
  65  *   F      |               |                  |               |         *
  66  *          |               |                  |               |         *
  67  *                                                                       *
  68  * Gains vary from 0.126 up to 7.943, which means from -18dB attenuation *
  69  * up to +18dB amplification. Band width varies from 0.01 up to 1.0 in   *
  70  * octaves for two mid bands.                                            *
  71  *                                                                       *
  72  * Implementation is based on the "Cookbook formulae for audio EQ biquad *
  73  * filter coefficients" by Robert Bristow-Johnson                        *
  74  * http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt                   */
  75
  76
  77 struct ALequalizerState final : public ALeffectState {
  78     struct {
  79         /* Effect parameters */
  80         BiquadFilter filter[4];
  81
  82         /* Effect gains for each channel */
  83         ALfloat CurrentGains[MAX_OUTPUT_CHANNELS];
  84         ALfloat TargetGains[MAX_OUTPUT_CHANNELS];
  85     } Chans[MAX_EFFECT_CHANNELS];
  86
  87     ALfloat SampleBuffer[MAX_EFFECT_CHANNELS][BUFFERSIZE];
  88 };
  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     new (state) ALequalizerState{};
 102     ALeffectState_Construct(STATIC_CAST(ALeffectState, state));
 103     SET_VTABLE2(ALequalizerState, ALeffectState, state);
 104 }
 105
 106 static ALvoid ALequalizerState_Destruct(ALequalizerState *state)
 107 {
 108     ALeffectState_Destruct(STATIC_CAST(ALeffectState,state));
 109     state->~ALequalizerState();
 110 }
 111
 112 static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *state, ALCdevice *UNUSED(device))
 113 {
 114     ALsizei i, j;
 115
 116     for(i = 0; i < MAX_EFFECT_CHANNELS;i++)
 117     {
 118         for(j = 0;j < 4;j++)
 119             BiquadFilter_clear(&state->Chans[i].filter[j]);
 120         for(j = 0;j < MAX_OUTPUT_CHANNELS;j++)
 121             state->Chans[i].CurrentGains[j] = 0.0f;
 122     }
 123     return AL_TRUE;
 124 }
 125
 126 static ALvoid ALequalizerState_update(ALequalizerState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props)
 127 {
 128     const ALCdevice *device = context->Device;
 129     ALfloat frequency = (ALfloat)device->Frequency;
 130     ALfloat gain, f0norm;
 131     ALuint i;
 132
 133     /* Calculate coefficients for the each type of filter. Note that the shelf
 134      * filters' gain is for the reference frequency, which is the centerpoint
 135      * of the transition band.
 136      */
 137     gain = maxf(sqrtf(props->Equalizer.LowGain), 0.0625f); /* Limit -24dB */
 138     f0norm = props->Equalizer.LowCutoff/frequency;
 139     BiquadFilter_setParams(&state->Chans[0].filter[0], BiquadType_LowShelf,
 140         gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f)
 141     );
 142
 143     gain = maxf(props->Equalizer.Mid1Gain, 0.0625f);
 144     f0norm = props->Equalizer.Mid1Center/frequency;
 145     BiquadFilter_setParams(&state->Chans[0].filter[1], BiquadType_Peaking,
 146         gain, f0norm, calc_rcpQ_from_bandwidth(
 147             f0norm, props->Equalizer.Mid1Width
 148         )
 149     );
 150
 151     gain = maxf(props->Equalizer.Mid2Gain, 0.0625f);
 152     f0norm = props->Equalizer.Mid2Center/frequency;
 153     BiquadFilter_setParams(&state->Chans[0].filter[2], BiquadType_Peaking,
 154         gain, f0norm, calc_rcpQ_from_bandwidth(
 155             f0norm, props->Equalizer.Mid2Width
 156         )
 157     );
 158
 159     gain = maxf(sqrtf(props->Equalizer.HighGain), 0.0625f);
 160     f0norm = props->Equalizer.HighCutoff/frequency;
 161     BiquadFilter_setParams(&state->Chans[0].filter[3], BiquadType_HighShelf,
 162         gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f)
 163     );
 164
 165     /* Copy the filter coefficients for the other input channels. */
 166     for(i = 1;i < MAX_EFFECT_CHANNELS;i++)
 167     {
 168         BiquadFilter_copyParams(&state->Chans[i].filter[0], &state->Chans[0].filter[0]);
 169         BiquadFilter_copyParams(&state->Chans[i].filter[1], &state->Chans[0].filter[1]);
 170         BiquadFilter_copyParams(&state->Chans[i].filter[2], &state->Chans[0].filter[2]);
 171         BiquadFilter_copyParams(&state->Chans[i].filter[3], &state->Chans[0].filter[3]);
 172     }
 173
 174     STATIC_CAST(ALeffectState,state)->OutBuffer = device->FOAOut.Buffer;
 175     STATIC_CAST(ALeffectState,state)->OutChannels = device->FOAOut.NumChannels;
 176     for(i = 0;i < MAX_EFFECT_CHANNELS;i++)
 177         ComputePanGains(&device->FOAOut, aluMatrixf::Identity.m[i], slot->Params.Gain,
 178                         state->Chans[i].TargetGains);
 179 }
 180
 181 static ALvoid ALequalizerState_process(ALequalizerState *state, ALsizei SamplesToDo, const ALfloat (*RESTRICT SamplesIn)[BUFFERSIZE], ALfloat (*RESTRICT SamplesOut)[BUFFERSIZE], ALsizei NumChannels)
 182 {
 183     ALfloat (*RESTRICT temps)[BUFFERSIZE] = state->SampleBuffer;
 184     ALsizei c;
 185
 186     for(c = 0;c < MAX_EFFECT_CHANNELS;c++)
 187     {
 188         BiquadFilter_process(&state->Chans[c].filter[0], temps[0], SamplesIn[c], SamplesToDo);
 189         BiquadFilter_process(&state->Chans[c].filter[1], temps[1], temps[0], SamplesToDo);
 190         BiquadFilter_process(&state->Chans[c].filter[2], temps[2], temps[1], SamplesToDo);
 191         BiquadFilter_process(&state->Chans[c].filter[3], temps[3], temps[2], SamplesToDo);
 192
 193         MixSamples(temps[3], NumChannels, SamplesOut,
 194             state->Chans[c].CurrentGains, state->Chans[c].TargetGains,
 195             SamplesToDo, 0, SamplesToDo
 196         );
 197     }
 198 }
 199
 200
 201 struct EqualizerStateFactory final : public EffectStateFactory {
 202     ALeffectState *create() override;
 203 };
 204
 205 ALeffectState *EqualizerStateFactory::create()
 206 {
 207     ALequalizerState *state;
 208     NEW_OBJ0(state, ALequalizerState)();
 209     return state;
 210 }
 211
 212 EffectStateFactory *EqualizerStateFactory_getFactory(void)
 213 {
 214     static EqualizerStateFactory EqualizerFactory{};
 215     return &EqualizerFactory;
 216 }
 217
 218
 219 void ALequalizer_setParami(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint UNUSED(val))
 220 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); }
 221 void ALequalizer_setParamiv(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, const ALint *UNUSED(vals))
 222 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); }
 223 void ALequalizer_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
 224 {
 225     ALeffectProps *props = &effect->Props;
 226     switch(param)
 227     {
 228         case AL_EQUALIZER_LOW_GAIN:
 229             if(!(val >= AL_EQUALIZER_MIN_LOW_GAIN && val <= AL_EQUALIZER_MAX_LOW_GAIN))
 230                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band gain out of range");
 231             props->Equalizer.LowGain = val;
 232             break;
 233
 234         case AL_EQUALIZER_LOW_CUTOFF:
 235             if(!(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF))
 236                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band cutoff out of range");
 237             props->Equalizer.LowCutoff = val;
 238             break;
 239
 240         case AL_EQUALIZER_MID1_GAIN:
 241             if(!(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN))
 242                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band gain out of range");
 243             props->Equalizer.Mid1Gain = val;
 244             break;
 245
 246         case AL_EQUALIZER_MID1_CENTER:
 247             if(!(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER))
 248                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band center out of range");
 249             props->Equalizer.Mid1Center = val;
 250             break;
 251
 252         case AL_EQUALIZER_MID1_WIDTH:
 253             if(!(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH))
 254                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band width out of range");
 255             props->Equalizer.Mid1Width = val;
 256             break;
 257
 258         case AL_EQUALIZER_MID2_GAIN:
 259             if(!(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN))
 260                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band gain out of range");
 261             props->Equalizer.Mid2Gain = val;
 262             break;
 263
 264         case AL_EQUALIZER_MID2_CENTER:
 265             if(!(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER))
 266                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band center out of range");
 267             props->Equalizer.Mid2Center = val;
 268             break;
 269
 270         case AL_EQUALIZER_MID2_WIDTH:
 271             if(!(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH))
 272                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band width out of range");
 273             props->Equalizer.Mid2Width = val;
 274             break;
 275
 276         case AL_EQUALIZER_HIGH_GAIN:
 277             if(!(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN))
 278                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band gain out of range");
 279             props->Equalizer.HighGain = val;
 280             break;
 281
 282         case AL_EQUALIZER_HIGH_CUTOFF:
 283             if(!(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF))
 284                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band cutoff out of range");
 285             props->Equalizer.HighCutoff = val;
 286             break;
 287
 288         default:
 289             alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param);
 290     }
 291 }
 292 void ALequalizer_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
 293 { ALequalizer_setParamf(effect, context, param, vals[0]); }
 294
 295 void ALequalizer_getParami(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint *UNUSED(val))
 296 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); }
 297 void ALequalizer_getParamiv(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint *UNUSED(vals))
 298 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); }
 299 void ALequalizer_getParamf(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
 300 {
 301     const ALeffectProps *props = &effect->Props;
 302     switch(param)
 303     {
 304         case AL_EQUALIZER_LOW_GAIN:
 305             *val = props->Equalizer.LowGain;
 306             break;
 307
 308         case AL_EQUALIZER_LOW_CUTOFF:
 309             *val = props->Equalizer.LowCutoff;
 310             break;
 311
 312         case AL_EQUALIZER_MID1_GAIN:
 313             *val = props->Equalizer.Mid1Gain;
 314             break;
 315
 316         case AL_EQUALIZER_MID1_CENTER:
 317             *val = props->Equalizer.Mid1Center;
 318             break;
 319
 320         case AL_EQUALIZER_MID1_WIDTH:
 321             *val = props->Equalizer.Mid1Width;
 322             break;
 323
 324         case AL_EQUALIZER_MID2_GAIN:
 325             *val = props->Equalizer.Mid2Gain;
 326             break;
 327
 328         case AL_EQUALIZER_MID2_CENTER:
 329             *val = props->Equalizer.Mid2Center;
 330             break;
 331
 332         case AL_EQUALIZER_MID2_WIDTH:
 333             *val = props->Equalizer.Mid2Width;
 334             break;
 335
 336         case AL_EQUALIZER_HIGH_GAIN:
 337             *val = props->Equalizer.HighGain;
 338             break;
 339
 340         case AL_EQUALIZER_HIGH_CUTOFF:
 341             *val = props->Equalizer.HighCutoff;
 342             break;
 343
 344         default:
 345             alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param);
 346     }
 347 }
 348 void ALequalizer_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
 349 { ALequalizer_getParamf(effect, context, param, vals); }
 350
 351 DEFINE_ALEFFECT_VTABLE(ALequalizer);