/** * OpenAL cross platform audio library * Copyright (C) 2013 by Mike Gorchak * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * Or go to http://www.gnu.org/copyleft/lgpl.html */ #include "config.h" #include #include #include "alMain.h" #include "alFilter.h" #include "alAuxEffectSlot.h" #include "alError.h" #include "alu.h" /* The document "Effects Extension Guide.pdf" says that low and high * * frequencies are cutoff frequencies. This is not fully correct, they * * are corner frequencies for low and high shelf filters. If they were * * just cutoff frequencies, there would be no need in cutoff frequency * * gains, which are present. Documentation for "Creative Proteus X2" * * software describes 4-band equalizer functionality in a much better * * way. This equalizer seems to be a predecessor of OpenAL 4-band * * equalizer. With low and high shelf filters we are able to cutoff * * frequencies below and/or above corner frequencies using attenuation * * gains (below 1.0) and amplify all low and/or high frequencies using * * gains above 1.0. * * * * Low-shelf Low Mid Band High Mid Band High-shelf * * corner center center corner * * frequency frequency frequency frequency * * 50Hz..800Hz 200Hz..3000Hz 1000Hz..8000Hz 4000Hz..16000Hz * * * * | | | | * * | | | | * * B -----+ /--+--\ /--+--\ +----- * * O |\ | | | | | | /| * * O | \ - | - - | - / | * * S + | \ | | | | | | / | * * T | | | | | | | | | | * * ---------+---------------+------------------+---------------+-------- * * C | | | | | | | | | | * * U - | / | | | | | | \ | * * T | / - | - - | - \ | * * O |/ | | | | | | \| * * F -----+ \--+--/ \--+--/ +----- * * F | | | | * * | | | | * * * * Gains vary from 0.126 up to 7.943, which means from -18dB attenuation * * up to +18dB amplification. Band width varies from 0.01 up to 1.0 in * * octaves for two mid bands. * * * * Implementation is based on the "Cookbook formulae for audio EQ biquad * * filter coefficients" by Robert Bristow-Johnson * * http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt */ typedef struct ALequalizerState { DERIVE_FROM_TYPE(ALeffectState); struct { /* Effect gains for each channel */ ALfloat CurrentGains[MAX_OUTPUT_CHANNELS]; ALfloat TargetGains[MAX_OUTPUT_CHANNELS]; /* Effect parameters */ ALfilterState filter[4]; } Chans[MAX_EFFECT_CHANNELS]; ALfloat SampleBuffer[MAX_EFFECT_CHANNELS][BUFFERSIZE]; } ALequalizerState; static ALvoid ALequalizerState_Destruct(ALequalizerState *state); static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *state, ALCdevice *device); static ALvoid ALequalizerState_update(ALequalizerState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props); static ALvoid ALequalizerState_process(ALequalizerState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels); DECLARE_DEFAULT_ALLOCATORS(ALequalizerState) DEFINE_ALEFFECTSTATE_VTABLE(ALequalizerState); static void ALequalizerState_Construct(ALequalizerState *state) { ALeffectState_Construct(STATIC_CAST(ALeffectState, state)); SET_VTABLE2(ALequalizerState, ALeffectState, state); } static ALvoid ALequalizerState_Destruct(ALequalizerState *state) { ALeffectState_Destruct(STATIC_CAST(ALeffectState,state)); } static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *state, ALCdevice *UNUSED(device)) { ALsizei i, j; for(i = 0; i < MAX_EFFECT_CHANNELS;i++) { for(j = 0;j < 4;j++) ALfilterState_clear(&state->Chans[i].filter[j]); for(j = 0;j < MAX_OUTPUT_CHANNELS;j++) state->Chans[i].CurrentGains[j] = 0.0f; } return AL_TRUE; } static ALvoid ALequalizerState_update(ALequalizerState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props) { const ALCdevice *device = context->Device; ALfloat frequency = (ALfloat)device->Frequency; ALfloat gain, f0norm; ALuint i; STATIC_CAST(ALeffectState,state)->OutBuffer = device->FOAOut.Buffer; STATIC_CAST(ALeffectState,state)->OutChannels = device->FOAOut.NumChannels; for(i = 0;i < MAX_EFFECT_CHANNELS;i++) ComputeFirstOrderGains(&device->FOAOut, IdentityMatrixf.m[i], slot->Params.Gain, state->Chans[i].TargetGains); /* Calculate coefficients for the each type of filter. Note that the shelf * filters' gain is for the reference frequency, which is the centerpoint * of the transition band. */ gain = maxf(sqrtf(props->Equalizer.LowGain), 0.0625f); /* Limit -24dB */ f0norm = props->Equalizer.LowCutoff/frequency; ALfilterState_setParams(&state->Chans[0].filter[0], ALfilterType_LowShelf, gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f) ); gain = maxf(props->Equalizer.Mid1Gain, 0.0625f); f0norm = props->Equalizer.Mid1Center/frequency; ALfilterState_setParams(&state->Chans[0].filter[1], ALfilterType_Peaking, gain, f0norm, calc_rcpQ_from_bandwidth( f0norm, props->Equalizer.Mid1Width ) ); gain = maxf(props->Equalizer.Mid2Gain, 0.0625f); f0norm = props->Equalizer.Mid2Center/frequency; ALfilterState_setParams(&state->Chans[0].filter[2], ALfilterType_Peaking, gain, f0norm, calc_rcpQ_from_bandwidth( f0norm, props->Equalizer.Mid2Width ) ); gain = maxf(sqrtf(props->Equalizer.HighGain), 0.0625f); f0norm = props->Equalizer.HighCutoff/frequency; ALfilterState_setParams(&state->Chans[0].filter[3], ALfilterType_HighShelf, gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f) ); /* Copy the filter coefficients for the other input channels. */ for(i = 1;i < MAX_EFFECT_CHANNELS;i++) { ALfilterState_copyParams(&state->Chans[i].filter[0], &state->Chans[0].filter[0]); ALfilterState_copyParams(&state->Chans[i].filter[1], &state->Chans[0].filter[1]); ALfilterState_copyParams(&state->Chans[i].filter[2], &state->Chans[0].filter[2]); ALfilterState_copyParams(&state->Chans[i].filter[3], &state->Chans[0].filter[3]); } } static ALvoid ALequalizerState_process(ALequalizerState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels) { ALfloat (*restrict temps)[BUFFERSIZE] = state->SampleBuffer; ALsizei c; for(c = 0;c < MAX_EFFECT_CHANNELS;c++) { ALfilterState_process(&state->Chans[c].filter[0], temps[0], SamplesIn[c], SamplesToDo); ALfilterState_process(&state->Chans[c].filter[1], temps[1], temps[0], SamplesToDo); ALfilterState_process(&state->Chans[c].filter[2], temps[2], temps[1], SamplesToDo); ALfilterState_process(&state->Chans[c].filter[3], temps[3], temps[2], SamplesToDo); MixSamples(temps[3], NumChannels, SamplesOut, state->Chans[c].CurrentGains, state->Chans[c].TargetGains, SamplesToDo, 0, SamplesToDo ); } } typedef struct ALequalizerStateFactory { DERIVE_FROM_TYPE(ALeffectStateFactory); } ALequalizerStateFactory; ALeffectState *ALequalizerStateFactory_create(ALequalizerStateFactory *UNUSED(factory)) { ALequalizerState *state; NEW_OBJ0(state, ALequalizerState)(); if(!state) return NULL; return STATIC_CAST(ALeffectState, state); } DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALequalizerStateFactory); ALeffectStateFactory *ALequalizerStateFactory_getFactory(void) { static ALequalizerStateFactory EqualizerFactory = { { GET_VTABLE2(ALequalizerStateFactory, ALeffectStateFactory) } }; return STATIC_CAST(ALeffectStateFactory, &EqualizerFactory); } void ALequalizer_setParami(ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALint UNUSED(val)) { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); } void ALequalizer_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals) { ALequalizer_setParami(effect, context, param, vals[0]); } void ALequalizer_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val) { ALeffectProps *props = &effect->Props; switch(param) { case AL_EQUALIZER_LOW_GAIN: if(!(val >= AL_EQUALIZER_MIN_LOW_GAIN && val <= AL_EQUALIZER_MAX_LOW_GAIN)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.LowGain = val; break; case AL_EQUALIZER_LOW_CUTOFF: if(!(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.LowCutoff = val; break; case AL_EQUALIZER_MID1_GAIN: if(!(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.Mid1Gain = val; break; case AL_EQUALIZER_MID1_CENTER: if(!(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.Mid1Center = val; break; case AL_EQUALIZER_MID1_WIDTH: if(!(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.Mid1Width = val; break; case AL_EQUALIZER_MID2_GAIN: if(!(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.Mid2Gain = val; break; case AL_EQUALIZER_MID2_CENTER: if(!(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.Mid2Center = val; break; case AL_EQUALIZER_MID2_WIDTH: if(!(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.Mid2Width = val; break; case AL_EQUALIZER_HIGH_GAIN: if(!(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.HighGain = val; break; case AL_EQUALIZER_HIGH_CUTOFF: if(!(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF)) SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE); props->Equalizer.HighCutoff = val; break; default: SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); } } void ALequalizer_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals) { ALequalizer_setParamf(effect, context, param, vals[0]); } void ALequalizer_getParami(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALint *UNUSED(val)) { SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); } void ALequalizer_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals) { ALequalizer_getParami(effect, context, param, vals); } void ALequalizer_getParamf(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val) { const ALeffectProps *props = &effect->Props; switch(param) { case AL_EQUALIZER_LOW_GAIN: *val = props->Equalizer.LowGain; break; case AL_EQUALIZER_LOW_CUTOFF: *val = props->Equalizer.LowCutoff; break; case AL_EQUALIZER_MID1_GAIN: *val = props->Equalizer.Mid1Gain; break; case AL_EQUALIZER_MID1_CENTER: *val = props->Equalizer.Mid1Center; break; case AL_EQUALIZER_MID1_WIDTH: *val = props->Equalizer.Mid1Width; break; case AL_EQUALIZER_MID2_GAIN: *val = props->Equalizer.Mid2Gain; break; case AL_EQUALIZER_MID2_CENTER: *val = props->Equalizer.Mid2Center; break; case AL_EQUALIZER_MID2_WIDTH: *val = props->Equalizer.Mid2Width; break; case AL_EQUALIZER_HIGH_GAIN: *val = props->Equalizer.HighGain; break; case AL_EQUALIZER_HIGH_CUTOFF: *val = props->Equalizer.HighCutoff; break; default: SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); } } void ALequalizer_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals) { ALequalizer_getParamf(effect, context, param, vals); } DEFINE_ALEFFECT_VTABLE(ALequalizer);