Implement the Compressor effect

Alc/ALc.c

@@ -526,9 +526,7 @@ static const ALCenums enumeration[] = {
 #endif
     DECL(AL_EFFECT_RING_MODULATOR),
     DECL(AL_EFFECT_AUTOWAH),
-#if 0
     DECL(AL_EFFECT_COMPRESSOR),
-#endif
     DECL(AL_EFFECT_EQUALIZER),
     DECL(AL_EFFECT_DEDICATED_LOW_FREQUENCY_EFFECT),
     DECL(AL_EFFECT_DEDICATED_DIALOGUE),
@@ -571,12 +569,6 @@ static const ALCenums enumeration[] = {
     DECL(AL_REVERB_ROOM_ROLLOFF_FACTOR),
     DECL(AL_REVERB_DECAY_HFLIMIT),
 
-    DECL(AL_ECHO_DELAY),
-    DECL(AL_ECHO_LRDELAY),
-    DECL(AL_ECHO_DAMPING),
-    DECL(AL_ECHO_FEEDBACK),
-    DECL(AL_ECHO_SPREAD),
-
     DECL(AL_CHORUS_WAVEFORM),
     DECL(AL_CHORUS_PHASE),
     DECL(AL_CHORUS_RATE),
@@ -584,6 +576,18 @@ static const ALCenums enumeration[] = {
     DECL(AL_CHORUS_FEEDBACK),
     DECL(AL_CHORUS_DELAY),
 
+    DECL(AL_DISTORTION_EDGE),
+    DECL(AL_DISTORTION_GAIN),
+    DECL(AL_DISTORTION_LOWPASS_CUTOFF),
+    DECL(AL_DISTORTION_EQCENTER),
+    DECL(AL_DISTORTION_EQBANDWIDTH),
+
+    DECL(AL_ECHO_DELAY),
+    DECL(AL_ECHO_LRDELAY),
+    DECL(AL_ECHO_DAMPING),
+    DECL(AL_ECHO_FEEDBACK),
+    DECL(AL_ECHO_SPREAD),
+
     DECL(AL_FLANGER_WAVEFORM),
     DECL(AL_FLANGER_PHASE),
     DECL(AL_FLANGER_RATE),
@@ -591,6 +595,12 @@ static const ALCenums enumeration[] = {
     DECL(AL_FLANGER_FEEDBACK),
     DECL(AL_FLANGER_DELAY),
 
+    DECL(AL_RING_MODULATOR_FREQUENCY),
+    DECL(AL_RING_MODULATOR_HIGHPASS_CUTOFF),
+    DECL(AL_RING_MODULATOR_WAVEFORM),
+
+    DECL(AL_COMPRESSOR_ONOFF),
+
     DECL(AL_EQUALIZER_LOW_GAIN),
     DECL(AL_EQUALIZER_LOW_CUTOFF),
     DECL(AL_EQUALIZER_MID1_GAIN),
@@ -602,16 +612,6 @@ static const ALCenums enumeration[] = {
     DECL(AL_EQUALIZER_HIGH_GAIN),
     DECL(AL_EQUALIZER_HIGH_CUTOFF),
 
-    DECL(AL_DISTORTION_EDGE),
-    DECL(AL_DISTORTION_GAIN),
-    DECL(AL_DISTORTION_LOWPASS_CUTOFF),
-    DECL(AL_DISTORTION_EQCENTER),
-    DECL(AL_DISTORTION_EQBANDWIDTH),
-
-    DECL(AL_RING_MODULATOR_FREQUENCY),
-    DECL(AL_RING_MODULATOR_HIGHPASS_CUTOFF),
-    DECL(AL_RING_MODULATOR_WAVEFORM),
-
     DECL(AL_DEDICATED_GAIN),
 
     { NULL, (ALCenum)0 }

Alc/effects/compressor.c

@@ -0,0 +1,216 @@
+/**
+ * OpenAL cross platform audio library
+ * Copyright (C) 2013 by Anis A. Hireche
+ * 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., 59 Temple Place - Suite 330,
+ *  Boston, MA  02111-1307, USA.
+ * Or go to http://www.gnu.org/copyleft/lgpl.html
+ */
+
+#include <stdlib.h>
+
+#include "config.h"
+#include "alError.h"
+#include "alMain.h"
+#include "alAuxEffectSlot.h"
+#include "alu.h"
+
+typedef struct ALcompressorStateFactory {
+    DERIVE_FROM_TYPE(ALeffectStateFactory);
+} ALcompressorStateFactory;
+
+static ALcompressorStateFactory CompressorFactory;
+
+
+typedef struct ALcompressorState {
+    DERIVE_FROM_TYPE(ALeffectState);
+
+    /* Effect gains for each channel */
+    ALfloat Gain[MaxChannels];
+
+    /* Effect parameters */
+    ALboolean Enabled;
+    ALfloat Envelope;
+    ALfloat EnvGain;
+    ALfloat Attack;
+    ALfloat Release;
+} ALcompressorState;
+
+static ALvoid ALcompressorState_Destruct(ALcompressorState *state)
+{
+    (void)state;
+}
+
+static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device)
+{
+    state->Attack = expf(-1.0f / (device->Frequency * 0.0001f));
+    state->Release = expf(-1.0f / (device->Frequency * 0.3f));
+    state->Envelope = 0.0f;
+    state->EnvGain = 1.0f;
+
+    return AL_TRUE;
+}
+
+static ALvoid ALcompressorState_update(ALcompressorState *state, ALCdevice *Device, const ALeffectslot *Slot)
+{
+    ALfloat gain;
+
+    state->Enabled = Slot->EffectProps.Compressor.OnOff;
+    /* FIXME: Could maybe use the compressor's attack/release to move the gain to 1? */
+    if(!state->Enabled)
+        state->EnvGain = 1.0f;
+
+    gain = sqrtf(1.0f / Device->NumChan) * Slot->Gain;
+    SetGains(Device, gain, state->Gain);
+}
+
+static ALvoid ALcompressorState_process(ALcompressorState *state, ALuint SamplesToDo, const ALfloat *SamplesIn, ALfloat (*SamplesOut)[BUFFERSIZE])
+{
+    ALfloat env = state->Envelope;
+    ALfloat envgain = state->EnvGain;
+    ALfloat tattack = state->Attack;
+    ALfloat trelease = state->Release;
+    ALuint it, kt;
+    ALuint base;
+    ALfloat theta;
+    ALfloat rms;
+
+    for(base = 0;base < SamplesToDo;)
+    {
+        ALfloat temps[64];
+        ALuint td = minu(SamplesToDo-base, 64);
+        ALfloat summ = 0.0f;
+
+        for(it = 0;it < td;it++)
+        {
+            ALfloat smp = SamplesIn[it+base] * 0.5f;
+            summ += smp * smp;
+            temps[it] = smp;
+        }
+
+        if(state->Enabled)
+        {
+            const ALfloat threshold = 0.5f;
+            const ALfloat slope = 0.5f;
+
+            /* computing rms and envelope */
+            rms = sqrtf(summ / td);
+            theta = ((rms > env) ? tattack : trelease);
+            env = (1.0f - theta)*rms + theta*env;
+
+            /* applying a hard-knee rms based compressor */
+            if(env > threshold)
+                envgain = envgain - (env - threshold) * slope;
+        }
+
+        for(kt = 0;kt < MaxChannels;kt++)
+        {
+            ALfloat gain = state->Gain[kt] * envgain * 2.0f;
+            if(!(gain > 0.00001f))
+                continue;
+
+            for(it = 0;it < td;it++)
+                SamplesOut[kt][base+it] += gain * temps[it];
+        }
+
+        base += td;
+    }
+
+    state->Envelope = env;
+    state->EnvGain = envgain;
+}
+
+static void ALcompressorState_Delete(ALcompressorState *state)
+{
+    free(state);
+}
+
+DEFINE_ALEFFECTSTATE_VTABLE(ALcompressorState);
+
+
+static ALeffectState *ALcompressorStateFactory_create(ALcompressorStateFactory *factory)
+{
+    ALcompressorState *state;
+    (void)factory;
+
+    state = malloc(sizeof(*state));
+    if(!state) return NULL;
+    SET_VTABLE2(ALcompressorState, ALeffectState, state);
+
+    return STATIC_CAST(ALeffectState, state);
+}
+
+DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALcompressorStateFactory);
+
+ALeffectStateFactory *ALcompressorStateFactory_getFactory(void)
+{
+    SET_VTABLE2(ALcompressorStateFactory, ALeffectStateFactory, &CompressorFactory);
+    return STATIC_CAST(ALeffectStateFactory, &CompressorFactory);
+}
+
+
+void ALcompressor_setParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)
+{
+    ALeffectProps *props = &effect->Props;
+    switch(param)
+    {
+        case AL_COMPRESSOR_ONOFF:
+            if(!(val >= AL_COMPRESSOR_MIN_ONOFF && val <= AL_COMPRESSOR_MAX_ONOFF))
+                SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
+            props->Compressor.OnOff = val;
+            break;
+
+    default:
+        SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
+    }
+}
+
+void ALcompressor_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
+{
+    ALcompressor_setParami(effect, context, param, vals[0]);
+}
+
+void ALcompressor_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
+{SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); (void)effect;(void)param;(void)val;}
+
+void ALcompressor_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
+{
+    ALcompressor_setParamf(effect, context, param, vals[0]);
+}
+
+void ALcompressor_getParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)
+{ 
+    const ALeffectProps *props = &effect->Props;
+    switch(param)
+    {
+        case AL_COMPRESSOR_ONOFF:
+            *val = props->Compressor.OnOff;
+            break;
+        default:
+            SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
+    }
+}
+void ALcompressor_getParamiv(ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
+{
+    ALcompressor_getParami(effect, context, param, vals);
+}
+void ALcompressor_getParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
+{SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); (void)effect;(void)param;(void)val;}
+
+void ALcompressor_getParamfv(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
+{
+    ALcompressor_getParamf(effect, context, param, vals);
+}
+
+DEFINE_ALEFFECT_VTABLE(ALcompressor);

CMakeLists.txt

@@ -474,6 +474,7 @@ SET(ALC_OBJS  Alc/ALc.c
               Alc/bs2b.c
               Alc/effects/autowah.c
               Alc/effects/chorus.c
+              Alc/effects/compressor.c
               Alc/effects/dedicated.c
               Alc/effects/distortion.c
               Alc/effects/echo.c

OpenAL32/Include/alAuxEffectSlot.h

@@ -98,6 +98,7 @@ ALeffectStateFactory *ALnullStateFactory_getFactory(void);
 ALeffectStateFactory *ALreverbStateFactory_getFactory(void);
 ALeffectStateFactory *ALautowahStateFactory_getFactory(void);
 ALeffectStateFactory *ALchorusStateFactory_getFactory(void);
+ALeffectStateFactory *ALcompressorStateFactory_getFactory(void);
 ALeffectStateFactory *ALdistortionStateFactory_getFactory(void);
 ALeffectStateFactory *ALechoStateFactory_getFactory(void);
 ALeffectStateFactory *ALequalizerStateFactory_getFactory(void);

OpenAL32/Include/alEffect.h

@@ -14,6 +14,7 @@ enum {
     REVERB,
     AUTOWAH,
     CHORUS,
+    COMPRESSOR,
     DISTORTION,
     ECHO,
     EQUALIZER,
@@ -52,6 +53,7 @@ extern const struct ALeffectVtable ALeaxreverb_vtable;
 extern const struct ALeffectVtable ALreverb_vtable;
 extern const struct ALeffectVtable ALautowah_vtable;
 extern const struct ALeffectVtable ALchorus_vtable;
+extern const struct ALeffectVtable ALcompressor_vtable;
 extern const struct ALeffectVtable ALdistortion_vtable;
 extern const struct ALeffectVtable ALecho_vtable;
 extern const struct ALeffectVtable ALequalizer_vtable;
@@ -98,26 +100,6 @@ typedef union ALeffectProps {
         ALfloat Resonance;
     } Autowah;
 
-    struct {
-        ALfloat Delay;
-        ALfloat LRDelay;
-
-        ALfloat Damping;
-        ALfloat Feedback;
-
-        ALfloat Spread;
-    } Echo;
-
-    struct {
-        ALfloat Frequency;
-        ALfloat HighPassCutoff;
-        ALint Waveform;
-    } Modulator;
-
-    struct {
-        ALfloat Gain;
-    } Dedicated;
-
     struct {
         ALint Waveform;
         ALint Phase;
@@ -128,13 +110,26 @@ typedef union ALeffectProps {
     } Chorus;
 
     struct {
-        ALint Waveform;
-        ALint Phase;
-        ALfloat Rate;
-        ALfloat Depth;
-        ALfloat Feedback;
+        ALboolean OnOff;
+    } Compressor;
+
+    struct {
+        ALfloat Edge;
+        ALfloat Gain;
+        ALfloat LowpassCutoff;
+        ALfloat EQCenter;
+        ALfloat EQBandwidth;
+    } Distortion;
+
+    struct {
         ALfloat Delay;
-    } Flanger;
+        ALfloat LRDelay;
+
+        ALfloat Damping;
+        ALfloat Feedback;
+
+        ALfloat Spread;
+    } Echo;
 
     struct {
         ALfloat Delay;
@@ -151,12 +146,23 @@ typedef union ALeffectProps {
     } Equalizer;
 
     struct {
-        ALfloat Edge;
+        ALint Waveform;
+        ALint Phase;
+        ALfloat Rate;
+        ALfloat Depth;
+        ALfloat Feedback;
+        ALfloat Delay;
+    } Flanger;
+
+    struct {
+        ALfloat Frequency;
+        ALfloat HighPassCutoff;
+        ALint Waveform;
+    } Modulator;
+
+    struct {
         ALfloat Gain;
-        ALfloat LowpassCutoff;
-        ALfloat EQCenter;
-        ALfloat EQBandwidth;
-    } Distortion;
+    } Dedicated;
 } ALeffectProps;
 
 typedef struct ALeffect {

OpenAL32/alAuxEffectSlot.c

@@ -459,6 +459,7 @@ void InitEffectFactoryMap(void)
     InsertUIntMapEntry(&EffectStateFactoryMap, AL_EFFECT_REVERB, ALreverbStateFactory_getFactory);
     InsertUIntMapEntry(&EffectStateFactoryMap, AL_EFFECT_AUTOWAH, ALautowahStateFactory_getFactory);
     InsertUIntMapEntry(&EffectStateFactoryMap, AL_EFFECT_CHORUS, ALchorusStateFactory_getFactory);
+    InsertUIntMapEntry(&EffectStateFactoryMap, AL_EFFECT_COMPRESSOR, ALcompressorStateFactory_getFactory);
     InsertUIntMapEntry(&EffectStateFactoryMap, AL_EFFECT_DISTORTION, ALdistortionStateFactory_getFactory);
     InsertUIntMapEntry(&EffectStateFactoryMap, AL_EFFECT_ECHO, ALechoStateFactory_getFactory);
     InsertUIntMapEntry(&EffectStateFactoryMap, AL_EFFECT_EQUALIZER, ALequalizerStateFactory_getFactory);

OpenAL32/alEffect.c

@@ -429,6 +429,10 @@ static void InitEffectParams(ALeffect *effect, ALenum type)
         effect->Props.Chorus.Delay = AL_CHORUS_DEFAULT_DELAY;
         effect->vtbl = &ALchorus_vtable;
         break;
+    case AL_EFFECT_COMPRESSOR:
+        effect->Props.Compressor.OnOff = AL_COMPRESSOR_DEFAULT_ONOFF;
+        effect->vtbl = &ALcompressor_vtable;
+        break;
     case AL_EFFECT_DISTORTION:
         effect->Props.Distortion.Edge = AL_DISTORTION_DEFAULT_EDGE;
         effect->Props.Distortion.Gain = AL_DISTORTION_DEFAULT_GAIN;

OpenAL32/alExtension.c

@@ -40,6 +40,7 @@ const struct EffectList EffectList[] = {
     { "reverb",     REVERB,     "AL_EFFECT_REVERB",         AL_EFFECT_REVERB },
     { "autowah",    AUTOWAH,    "AL_EFFECT_AUTOWAH",        AL_EFFECT_AUTOWAH },
     { "chorus",     CHORUS,     "AL_EFFECT_CHORUS",         AL_EFFECT_CHORUS },
+    { "compressor", COMPRESSOR, "AL_EFFECT_COMPRESSOR",     AL_EFFECT_COMPRESSOR },
     { "distortion", DISTORTION, "AL_EFFECT_DISTORTION",     AL_EFFECT_DISTORTION },
     { "echo",       ECHO,       "AL_EFFECT_ECHO",           AL_EFFECT_ECHO },
     { "equalizer",  EQUALIZER,  "AL_EFFECT_EQUALIZER",      AL_EFFECT_EQUALIZER },

alsoftrc.sample

@@ -127,7 +127,7 @@
 #  Sets which effects to exclude, preventing apps from using them. This can
 #  help for apps that try to use effects which are too CPU intensive for the
 #  system to handle. Available effects are: eaxreverb,reverb,autowah,chorus,
-#  distortion,echo,equalizer,flanger,modulator,dedicated
+#  compressor,distortion,echo,equalizer,flanger,modulator,dedicated
 #excludefx =
 
 ## slots: