/** * 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 #include #include "alMain.h" #include "alcontext.h" #include "alAuxEffectSlot.h" #include "alError.h" #include "alu.h" #include "filters/biquad.h" #include "vecmat.h" namespace { /* 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 */ struct ALequalizerState final : public EffectState { struct { /* Effect parameters */ BiquadFilter filter[4]; /* Effect gains for each channel */ ALfloat CurrentGains[MAX_OUTPUT_CHANNELS]{}; ALfloat TargetGains[MAX_OUTPUT_CHANNELS]{}; } mChans[MAX_EFFECT_CHANNELS]; ALfloat mSampleBuffer[BUFFERSIZE]{}; ALboolean deviceUpdate(const ALCdevice *device) override; void update(const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props, const EffectTarget target) override; void process(ALsizei samplesToDo, const ALfloat (*RESTRICT samplesIn)[BUFFERSIZE], ALfloat (*RESTRICT samplesOut)[BUFFERSIZE], ALsizei numChannels) override; DEF_NEWDEL(ALequalizerState) }; ALboolean ALequalizerState::deviceUpdate(const ALCdevice *UNUSED(device)) { for(auto &e : mChans) { std::for_each(std::begin(e.filter), std::end(e.filter), std::mem_fn(&BiquadFilter::clear)); std::fill(std::begin(e.CurrentGains), std::end(e.CurrentGains), 0.0f); } return AL_TRUE; } void ALequalizerState::update(const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props, const EffectTarget target) { const ALCdevice *device = context->Device; ALfloat frequency = static_cast(device->Frequency); ALfloat gain, f0norm; ALuint i; /* 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; mChans[0].filter[0].setParams(BiquadType::LowShelf, gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f) ); gain = maxf(props->Equalizer.Mid1Gain, 0.0625f); f0norm = props->Equalizer.Mid1Center/frequency; mChans[0].filter[1].setParams(BiquadType::Peaking, gain, f0norm, calc_rcpQ_from_bandwidth(f0norm, props->Equalizer.Mid1Width) ); gain = maxf(props->Equalizer.Mid2Gain, 0.0625f); f0norm = props->Equalizer.Mid2Center/frequency; mChans[0].filter[2].setParams(BiquadType::Peaking, gain, f0norm, calc_rcpQ_from_bandwidth(f0norm, props->Equalizer.Mid2Width) ); gain = maxf(sqrtf(props->Equalizer.HighGain), 0.0625f); f0norm = props->Equalizer.HighCutoff/frequency; mChans[0].filter[3].setParams(BiquadType::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++) { mChans[i].filter[0].copyParamsFrom(mChans[0].filter[0]); mChans[i].filter[1].copyParamsFrom(mChans[0].filter[1]); mChans[i].filter[2].copyParamsFrom(mChans[0].filter[2]); mChans[i].filter[3].copyParamsFrom(mChans[0].filter[3]); } mOutBuffer = target.FOAOut->Buffer; mOutChannels = target.FOAOut->NumChannels; for(i = 0;i < MAX_EFFECT_CHANNELS;i++) ComputePanGains(target.FOAOut, alu::Matrix::Identity()[i].data(), slot->Params.Gain, mChans[i].TargetGains); } void ALequalizerState::process(ALsizei SamplesToDo, const ALfloat (*RESTRICT SamplesIn)[BUFFERSIZE], ALfloat (*RESTRICT SamplesOut)[BUFFERSIZE], ALsizei NumChannels) { for(ALsizei c{0};c < MAX_EFFECT_CHANNELS;c++) { mChans[c].filter[0].process(mSampleBuffer, SamplesIn[c], SamplesToDo); mChans[c].filter[1].process(mSampleBuffer, mSampleBuffer, SamplesToDo); mChans[c].filter[2].process(mSampleBuffer, mSampleBuffer, SamplesToDo); mChans[c].filter[3].process(mSampleBuffer, mSampleBuffer, SamplesToDo); MixSamples(mSampleBuffer, NumChannels, SamplesOut, mChans[c].CurrentGains, mChans[c].TargetGains, SamplesToDo, 0, SamplesToDo); } } } // namespace struct EqualizerStateFactory final : public EffectStateFactory { EffectState *create() override; }; EffectState *EqualizerStateFactory::create() { return new ALequalizerState{}; } EffectStateFactory *EqualizerStateFactory_getFactory(void) { static EqualizerStateFactory EqualizerFactory{}; return &EqualizerFactory; } void ALequalizer_setParami(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint UNUSED(val)) { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); } void ALequalizer_setParamiv(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, const ALint *UNUSED(vals)) { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); } 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)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band gain out of range"); props->Equalizer.LowGain = val; break; case AL_EQUALIZER_LOW_CUTOFF: if(!(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band cutoff out of range"); props->Equalizer.LowCutoff = val; break; case AL_EQUALIZER_MID1_GAIN: if(!(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band gain out of range"); props->Equalizer.Mid1Gain = val; break; case AL_EQUALIZER_MID1_CENTER: if(!(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band center out of range"); props->Equalizer.Mid1Center = val; break; case AL_EQUALIZER_MID1_WIDTH: if(!(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band width out of range"); props->Equalizer.Mid1Width = val; break; case AL_EQUALIZER_MID2_GAIN: if(!(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band gain out of range"); props->Equalizer.Mid2Gain = val; break; case AL_EQUALIZER_MID2_CENTER: if(!(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band center out of range"); props->Equalizer.Mid2Center = val; break; case AL_EQUALIZER_MID2_WIDTH: if(!(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band width out of range"); props->Equalizer.Mid2Width = val; break; case AL_EQUALIZER_HIGH_GAIN: if(!(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band gain out of range"); props->Equalizer.HighGain = val; break; case AL_EQUALIZER_HIGH_CUTOFF: if(!(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF)) SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band cutoff out of range"); props->Equalizer.HighCutoff = val; break; default: alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param); } } 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 param, ALint *UNUSED(val)) { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); } void ALequalizer_getParamiv(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint *UNUSED(vals)) { alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); } 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: alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param); } } void ALequalizer_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals) { ALequalizer_getParamf(effect, context, param, vals); } DEFINE_ALEFFECT_VTABLE(ALequalizer);