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 <algorithm>
  27
  28 #include "alMain.h"
  29 #include "alcontext.h"
  30 #include "alAuxEffectSlot.h"
  31 #include "alError.h"
  32 #include "alu.h"
  33 #include "filters/defs.h"
  34 #include "vecmat.h"
  35
  36
  37 /*  The document  "Effects Extension Guide.pdf"  says that low and high  *
  38  *  frequencies are cutoff frequencies. This is not fully correct, they  *
  39  *  are corner frequencies for low and high shelf filters. If they were  *
  40  *  just cutoff frequencies, there would be no need in cutoff frequency  *
  41  *  gains, which are present.  Documentation for  "Creative Proteus X2"  *
  42  *  software describes  4-band equalizer functionality in a much better  *
  43  *  way.  This equalizer seems  to be a predecessor  of  OpenAL  4-band  *
  44  *  equalizer.  With low and high  shelf filters  we are able to cutoff  *
  45  *  frequencies below and/or above corner frequencies using attenuation  *
  46  *  gains (below 1.0) and amplify all low and/or high frequencies using  *
  47  *  gains above 1.0.                                                     *
  48  *                                                                       *
  49  *     Low-shelf       Low Mid Band      High Mid Band     High-shelf    *
  50  *      corner            center             center          corner      *
  51  *     frequency        frequency          frequency       frequency     *
  52  *    50Hz..800Hz     200Hz..3000Hz      1000Hz..8000Hz  4000Hz..16000Hz *
  53  *                                                                       *
  54  *          |               |                  |               |         *
  55  *          |               |                  |               |         *
  56  *   B -----+            /--+--\            /--+--\            +-----    *
  57  *   O      |\          |   |   |          |   |   |          /|         *
  58  *   O      | \        -    |    -        -    |    -        / |         *
  59  *   S +    |  \      |     |     |      |     |     |      /  |         *
  60  *   T      |   |    |      |      |    |      |      |    |   |         *
  61  * ---------+---------------+------------------+---------------+-------- *
  62  *   C      |   |    |      |      |    |      |      |    |   |         *
  63  *   U -    |  /      |     |     |      |     |     |      \  |         *
  64  *   T      | /        -    |    -        -    |    -        \ |         *
  65  *   O      |/          |   |   |          |   |   |          \|         *
  66  *   F -----+            \--+--/            \--+--/            +-----    *
  67  *   F      |               |                  |               |         *
  68  *          |               |                  |               |         *
  69  *                                                                       *
  70  * Gains vary from 0.126 up to 7.943, which means from -18dB attenuation *
  71  * up to +18dB amplification. Band width varies from 0.01 up to 1.0 in   *
  72  * octaves for two mid bands.                                            *
  73  *                                                                       *
  74  * Implementation is based on the "Cookbook formulae for audio EQ biquad *
  75  * filter coefficients" by Robert Bristow-Johnson                        *
  76  * http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt                   */
  77
  78
  79 struct ALequalizerState final : public ALeffectState {
  80     struct {
  81         /* Effect parameters */
  82         BiquadFilter filter[4];
  83
  84         /* Effect gains for each channel */
  85         ALfloat CurrentGains[MAX_OUTPUT_CHANNELS]{};
  86         ALfloat TargetGains[MAX_OUTPUT_CHANNELS]{};
  87     } mChans[MAX_EFFECT_CHANNELS];
  88
  89     ALfloat mSampleBuffer[MAX_EFFECT_CHANNELS][BUFFERSIZE]{};
  90 };
  91
  92 static ALvoid ALequalizerState_Destruct(ALequalizerState *state);
  93 static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *state, ALCdevice *device);
  94 static ALvoid ALequalizerState_update(ALequalizerState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props);
  95 static ALvoid ALequalizerState_process(ALequalizerState *state, ALsizei SamplesToDo, const ALfloat (*RESTRICT SamplesIn)[BUFFERSIZE], ALfloat (*RESTRICT SamplesOut)[BUFFERSIZE], ALsizei NumChannels);
  96 DECLARE_DEFAULT_ALLOCATORS(ALequalizerState)
  97
  98 DEFINE_ALEFFECTSTATE_VTABLE(ALequalizerState);
  99
 100
 101 static void ALequalizerState_Construct(ALequalizerState *state)
 102 {
 103     new (state) ALequalizerState{};
 104     ALeffectState_Construct(STATIC_CAST(ALeffectState, state));
 105     SET_VTABLE2(ALequalizerState, ALeffectState, state);
 106 }
 107
 108 static ALvoid ALequalizerState_Destruct(ALequalizerState *state)
 109 {
 110     ALeffectState_Destruct(STATIC_CAST(ALeffectState,state));
 111     state->~ALequalizerState();
 112 }
 113
 114 static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *state, ALCdevice *UNUSED(device))
 115 {
 116     for(auto &e : state->mChans)
 117     {
 118         std::for_each(std::begin(e.filter), std::end(e.filter),
 119             [](BiquadFilter &f) -> void
 120             { BiquadFilter_clear(&f); }
 121         );
 122         std::fill(std::begin(e.CurrentGains), std::end(e.CurrentGains), 0.0f);
 123     }
 124     return AL_TRUE;
 125 }
 126
 127 static ALvoid ALequalizerState_update(ALequalizerState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props)
 128 {
 129     const ALCdevice *device = context->Device;
 130     ALfloat frequency = (ALfloat)device->Frequency;
 131     ALfloat gain, f0norm;
 132     ALuint i;
 133
 134     /* Calculate coefficients for the each type of filter. Note that the shelf
 135      * filters' gain is for the reference frequency, which is the centerpoint
 136      * of the transition band.
 137      */
 138     gain = maxf(sqrtf(props->Equalizer.LowGain), 0.0625f); /* Limit -24dB */
 139     f0norm = props->Equalizer.LowCutoff/frequency;
 140     BiquadFilter_setParams(&state->mChans[0].filter[0], BiquadType::LowShelf,
 141         gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f)
 142     );
 143
 144     gain = maxf(props->Equalizer.Mid1Gain, 0.0625f);
 145     f0norm = props->Equalizer.Mid1Center/frequency;
 146     BiquadFilter_setParams(&state->mChans[0].filter[1], BiquadType::Peaking,
 147         gain, f0norm, calc_rcpQ_from_bandwidth(
 148             f0norm, props->Equalizer.Mid1Width
 149         )
 150     );
 151
 152     gain = maxf(props->Equalizer.Mid2Gain, 0.0625f);
 153     f0norm = props->Equalizer.Mid2Center/frequency;
 154     BiquadFilter_setParams(&state->mChans[0].filter[2], BiquadType::Peaking,
 155         gain, f0norm, calc_rcpQ_from_bandwidth(
 156             f0norm, props->Equalizer.Mid2Width
 157         )
 158     );
 159
 160     gain = maxf(sqrtf(props->Equalizer.HighGain), 0.0625f);
 161     f0norm = props->Equalizer.HighCutoff/frequency;
 162     BiquadFilter_setParams(&state->mChans[0].filter[3], BiquadType::HighShelf,
 163         gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f)
 164     );
 165
 166     /* Copy the filter coefficients for the other input channels. */
 167     for(i = 1;i < MAX_EFFECT_CHANNELS;i++)
 168     {
 169         BiquadFilter_copyParams(&state->mChans[i].filter[0], &state->mChans[0].filter[0]);
 170         BiquadFilter_copyParams(&state->mChans[i].filter[1], &state->mChans[0].filter[1]);
 171         BiquadFilter_copyParams(&state->mChans[i].filter[2], &state->mChans[0].filter[2]);
 172         BiquadFilter_copyParams(&state->mChans[i].filter[3], &state->mChans[0].filter[3]);
 173     }
 174
 175     state->OutBuffer = device->FOAOut.Buffer;
 176     state->OutChannels = device->FOAOut.NumChannels;
 177     for(i = 0;i < MAX_EFFECT_CHANNELS;i++)
 178         ComputePanGains(&device->FOAOut, aluMatrixf::Identity.m[i], slot->Params.Gain,
 179                         state->mChans[i].TargetGains);
 180 }
 181
 182 static ALvoid ALequalizerState_process(ALequalizerState *state, ALsizei SamplesToDo, const ALfloat (*RESTRICT SamplesIn)[BUFFERSIZE], ALfloat (*RESTRICT SamplesOut)[BUFFERSIZE], ALsizei NumChannels)
 183 {
 184     ALfloat (*RESTRICT temps)[BUFFERSIZE] = state->mSampleBuffer;
 185     ALsizei c;
 186
 187     for(c = 0;c < MAX_EFFECT_CHANNELS;c++)
 188     {
 189         BiquadFilter_process(&state->mChans[c].filter[0], temps[0], SamplesIn[c], SamplesToDo);
 190         BiquadFilter_process(&state->mChans[c].filter[1], temps[1], temps[0], SamplesToDo);
 191         BiquadFilter_process(&state->mChans[c].filter[2], temps[2], temps[1], SamplesToDo);
 192         BiquadFilter_process(&state->mChans[c].filter[3], temps[3], temps[2], SamplesToDo);
 193
 194         MixSamples(temps[3], NumChannels, SamplesOut,
 195             state->mChans[c].CurrentGains, state->mChans[c].TargetGains,
 196             SamplesToDo, 0, SamplesToDo
 197         );
 198     }
 199 }
 200
 201
 202 struct EqualizerStateFactory final : public EffectStateFactory {
 203     ALeffectState *create() override;
 204 };
 205
 206 ALeffectState *EqualizerStateFactory::create()
 207 {
 208     ALequalizerState *state;
 209     NEW_OBJ0(state, ALequalizerState)();
 210     return state;
 211 }
 212
 213 EffectStateFactory *EqualizerStateFactory_getFactory(void)
 214 {
 215     static EqualizerStateFactory EqualizerFactory{};
 216     return &EqualizerFactory;
 217 }
 218
 219
 220 void ALequalizer_setParami(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint UNUSED(val))
 221 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); }
 222 void ALequalizer_setParamiv(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, const ALint *UNUSED(vals))
 223 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); }
 224 void ALequalizer_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
 225 {
 226     ALeffectProps *props = &effect->Props;
 227     switch(param)
 228     {
 229         case AL_EQUALIZER_LOW_GAIN:
 230             if(!(val >= AL_EQUALIZER_MIN_LOW_GAIN && val <= AL_EQUALIZER_MAX_LOW_GAIN))
 231                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band gain out of range");
 232             props->Equalizer.LowGain = val;
 233             break;
 234
 235         case AL_EQUALIZER_LOW_CUTOFF:
 236             if(!(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF))
 237                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band cutoff out of range");
 238             props->Equalizer.LowCutoff = val;
 239             break;
 240
 241         case AL_EQUALIZER_MID1_GAIN:
 242             if(!(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN))
 243                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band gain out of range");
 244             props->Equalizer.Mid1Gain = val;
 245             break;
 246
 247         case AL_EQUALIZER_MID1_CENTER:
 248             if(!(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER))
 249                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band center out of range");
 250             props->Equalizer.Mid1Center = val;
 251             break;
 252
 253         case AL_EQUALIZER_MID1_WIDTH:
 254             if(!(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH))
 255                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band width out of range");
 256             props->Equalizer.Mid1Width = val;
 257             break;
 258
 259         case AL_EQUALIZER_MID2_GAIN:
 260             if(!(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN))
 261                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band gain out of range");
 262             props->Equalizer.Mid2Gain = val;
 263             break;
 264
 265         case AL_EQUALIZER_MID2_CENTER:
 266             if(!(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER))
 267                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band center out of range");
 268             props->Equalizer.Mid2Center = val;
 269             break;
 270
 271         case AL_EQUALIZER_MID2_WIDTH:
 272             if(!(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH))
 273                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band width out of range");
 274             props->Equalizer.Mid2Width = val;
 275             break;
 276
 277         case AL_EQUALIZER_HIGH_GAIN:
 278             if(!(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN))
 279                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band gain out of range");
 280             props->Equalizer.HighGain = val;
 281             break;
 282
 283         case AL_EQUALIZER_HIGH_CUTOFF:
 284             if(!(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF))
 285                 SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band cutoff out of range");
 286             props->Equalizer.HighCutoff = val;
 287             break;
 288
 289         default:
 290             alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param);
 291     }
 292 }
 293 void ALequalizer_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
 294 { ALequalizer_setParamf(effect, context, param, vals[0]); }
 295
 296 void ALequalizer_getParami(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint *UNUSED(val))
 297 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); }
 298 void ALequalizer_getParamiv(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint *UNUSED(vals))
 299 { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); }
 300 void ALequalizer_getParamf(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
 301 {
 302     const ALeffectProps *props = &effect->Props;
 303     switch(param)
 304     {
 305         case AL_EQUALIZER_LOW_GAIN:
 306             *val = props->Equalizer.LowGain;
 307             break;
 308
 309         case AL_EQUALIZER_LOW_CUTOFF:
 310             *val = props->Equalizer.LowCutoff;
 311             break;
 312
 313         case AL_EQUALIZER_MID1_GAIN:
 314             *val = props->Equalizer.Mid1Gain;
 315             break;
 316
 317         case AL_EQUALIZER_MID1_CENTER:
 318             *val = props->Equalizer.Mid1Center;
 319             break;
 320
 321         case AL_EQUALIZER_MID1_WIDTH:
 322             *val = props->Equalizer.Mid1Width;
 323             break;
 324
 325         case AL_EQUALIZER_MID2_GAIN:
 326             *val = props->Equalizer.Mid2Gain;
 327             break;
 328
 329         case AL_EQUALIZER_MID2_CENTER:
 330             *val = props->Equalizer.Mid2Center;
 331             break;
 332
 333         case AL_EQUALIZER_MID2_WIDTH:
 334             *val = props->Equalizer.Mid2Width;
 335             break;
 336
 337         case AL_EQUALIZER_HIGH_GAIN:
 338             *val = props->Equalizer.HighGain;
 339             break;
 340
 341         case AL_EQUALIZER_HIGH_CUTOFF:
 342             *val = props->Equalizer.HighCutoff;
 343             break;
 344
 345         default:
 346             alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param);
 347     }
 348 }
 349 void ALequalizer_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
 350 { ALequalizer_getParamf(effect, context, param, vals); }
 351
 352 DEFINE_ALEFFECT_VTABLE(ALequalizer);