EFX: Frequency Shifter implementation

Add frequency shifter effect using discrete Hilbert transform. Only mono signal processing by now (LEFT_DIRECTION).

1 files changed, 323 insertions, 0 deletions

diff --git a/Alc/effects/fshifter.c b/Alc/effects/fshifter.c
new file mode 100644
index 00000000..2d1b64fe
--- /dev/null
+++ b/Alc/effects/fshifter.c
@@ -0,0 +1,323 @@
+/**

+ * OpenAL cross platform audio library

+ * Copyright (C) 2018 by Raul Herraiz.

+ * 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 <math.h>

+#include <stdlib.h>

+

+#include "alMain.h"

+#include "alAuxEffectSlot.h"

+#include "alError.h"

+#include "alu.h"

+#include "filters/defs.h"

+

+#include "alcomplex.h"

+

+#define HIL_SIZE 1024

+#define OVERSAMP       (1<<2)

+

+#define HIL_STEP    (HIL_SIZE / OVERSAMP)

+#define FIFO_LATENCY (HIL_STEP * (OVERSAMP-1))

+

+

+typedef struct ALfshifterState {

+    DERIVE_FROM_TYPE(ALeffectState);

+

+    /* Effect parameters */

+    ALsizei  count;

+    ALdouble frac_freq;

+    ALdouble inc;

+    ALdouble ld_sign;

+

+    /*Effects buffers*/ 

+    ALfloat   InFIFO[HIL_SIZE];

+    ALcomplex OutFIFO[HIL_SIZE];

+    ALcomplex OutputAccum[2*HIL_SIZE];

+    ALcomplex Analytic[HIL_SIZE];

+    ALcomplex Outdata[BUFFERSIZE];

+

+    alignas(16) ALfloat BufferOut[BUFFERSIZE];

+

+    /* Effect gains for each output channel */

+    ALfloat CurrentGains[MAX_OUTPUT_CHANNELS];

+    ALfloat TargetGains[MAX_OUTPUT_CHANNELS];

+

+} ALfshifterState;

+

+static ALvoid ALfshifterState_Destruct(ALfshifterState *state);

+static ALboolean ALfshifterState_deviceUpdate(ALfshifterState *state, ALCdevice *device);

+static ALvoid ALfshifterState_update(ALfshifterState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props);

+static ALvoid ALfshifterState_process(ALfshifterState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels);

+DECLARE_DEFAULT_ALLOCATORS(ALfshifterState)

+

+DEFINE_ALEFFECTSTATE_VTABLE(ALfshifterState);

+

+/* Define a Hann window, used to filter the HIL input and output. */

+alignas(16) static ALdouble HannWindow[HIL_SIZE];

+

+static void InitHannWindow(void)

+{

+    ALsizei i;

+

+    /* Create lookup table of the Hann window for the desired size, i.e. HIL_SIZE */

+    for(i = 0;i < HIL_SIZE>>1;i++)

+    {

+        ALdouble val = sin(M_PI * (ALdouble)i / (ALdouble)(HIL_SIZE-1));

+        HannWindow[i] = HannWindow[HIL_SIZE-1-i] = val * val;

+    }

+}

+

+static alonce_flag HannInitOnce = AL_ONCE_FLAG_INIT;

+

+static void ALfshifterState_Construct(ALfshifterState *state)

+{

+    ALeffectState_Construct(STATIC_CAST(ALeffectState, state));

+    SET_VTABLE2(ALfshifterState, ALeffectState, state);

+

+    alcall_once(&HannInitOnce, InitHannWindow);

+}

+

+static ALvoid ALfshifterState_Destruct(ALfshifterState *state)

+{

+    ALeffectState_Destruct(STATIC_CAST(ALeffectState,state));

+}

+

+static ALboolean ALfshifterState_deviceUpdate(ALfshifterState *state, ALCdevice *device)

+{

+    /* (Re-)initializing parameters and clear the buffers. */

+    state->count       =  FIFO_LATENCY;

+    state->frac_freq   =  0.0;

+    state->inc         =  0.0;

+    state->ld_sign     = -1.0;

+

+    memset(state->InFIFO     , 0, HIL_SIZE*sizeof(ALfloat));

+    memset(state->OutFIFO    , 0, HIL_SIZE*sizeof(ALcomplex));

+    memset(state->OutputAccum, 0, 2*HIL_SIZE*sizeof(ALcomplex));

+    memset(state->Analytic   , 0, HIL_SIZE*sizeof(ALcomplex));

+

+    memset(state->CurrentGains, 0, sizeof(state->CurrentGains));

+    memset(state->TargetGains,  0, sizeof(state->TargetGains));

+

+    return AL_TRUE;

+}

+

+static ALvoid ALfshifterState_update(ALfshifterState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props)

+{

+    const ALCdevice *device = context->Device;

+    ALfloat coeffs[MAX_AMBI_COEFFS];

+

+    state->frac_freq = props->Fshifter.Frequency/device->Frequency;

+

+    switch (props->Fshifter.Left_direction)

+    {

+      case AL_FREQUENCY_SHIFTER_DIRECTION_DOWN:

+           state->ld_sign   = -1.0;

+      break;

+

+      case AL_FREQUENCY_SHIFTER_DIRECTION_UP:

+           state->ld_sign   =  1.0;

+      break;

+

+      case AL_FREQUENCY_SHIFTER_DIRECTION_OFF:

+           state->frac_freq =  0.0;

+      break;

+    }

+

+    CalcAngleCoeffs(0.0f, 0.0f, 0.0f, coeffs);

+    ComputeDryPanGains(&device->Dry, coeffs, slot->Params.Gain, state->TargetGains);

+}

+

+static ALvoid ALfshifterState_process(ALfshifterState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels)

+{

+    ALsizei i,k;

+    ALfloat *restrict BufferOut  = state->BufferOut;

+

+    for (i = 0; i < SamplesToDo; i++){

+

+        /* Fill FIFO buffer with samples data */

+        state->InFIFO[state->count] = SamplesIn[0][i];

+        state->Outdata[i]  = state->OutFIFO[state->count-FIFO_LATENCY];

+

+        state->count++;

+

+        /* Check whether FIFO buffer is filled */

+        if (state->count >= HIL_SIZE ) 

+        {

+            state->count = FIFO_LATENCY;

+

+            /* Real signal windowing and store in Analytic buffer */

+            for (k = 0; k < HIL_SIZE;k++) 

+            {

+                state->Analytic[k].Real = state->InFIFO[k] * HannWindow[k];

+                state->Analytic[k].Imag = 0.0f;

+            }

+            /*Processing signal by Discrete Hilbert Transform (analytical signal)*/

+            hilbert(HIL_SIZE, state->Analytic);

+

+            /* Windowing and add to output accumulator */ 

+            for(k=0; k < HIL_SIZE; k++) 

+            {

+                state->OutputAccum[k].Real  +=  2.0f*HannWindow[k]*state->Analytic[k].Real / OVERSAMP;

+                state->OutputAccum[k].Imag  +=  2.0f*HannWindow[k]*state->Analytic[k].Imag / OVERSAMP;

+            }

+            for (k = 0; k < HIL_STEP; k++) 

+            {

+                state->OutFIFO[k] = state->OutputAccum[k];

+            }

+

+            /* shift accumulator */

+            memmove(state->OutputAccum, state->OutputAccum + HIL_STEP, HIL_SIZE*sizeof(ALcomplex));

+

+            /* move input FIFO */

+            for (k = 0; k < FIFO_LATENCY; k++) state->InFIFO[k] = state->InFIFO[k + HIL_STEP];

+            }

+    }

+    /*Process frequency shifter using the analytic signal obtained*/

+    for ( k = 0; k < SamplesToDo; k++, state->inc += state->frac_freq ) 

+    {

+        ALdouble phase;

+

+        if( state->inc >= 1.0 )  state->inc -= 1.0;

+

+        phase = (2.0*M_PI*state->inc);

+

+        BufferOut[k] = (ALfloat)(state->Outdata[k].Real*cos(phase) + 

+                                 state->ld_sign*state->Outdata[k].Imag*sin(phase));

+    }

+

+    /* Now, mix the processed sound data to the output. */

+    MixSamples(BufferOut, NumChannels, SamplesOut, state->CurrentGains, state->TargetGains,

+               maxi(SamplesToDo, 512), 0, SamplesToDo);

+

+}

+

+typedef struct FshifterStateFactory {

+    DERIVE_FROM_TYPE(EffectStateFactory);

+} FshifterStateFactory;

+

+static ALeffectState *FshifterStateFactory_create(FshifterStateFactory *UNUSED(factory))

+{

+    ALfshifterState *state;

+

+    NEW_OBJ0(state, ALfshifterState)();

+    if(!state) return NULL;

+

+    return STATIC_CAST(ALeffectState, state);

+}

+

+DEFINE_EFFECTSTATEFACTORY_VTABLE(FshifterStateFactory);

+

+EffectStateFactory *FshifterStateFactory_getFactory(void)

+{

+    static FshifterStateFactory FshifterFactory = { { GET_VTABLE2(FshifterStateFactory, EffectStateFactory) } };

+

+    return STATIC_CAST(EffectStateFactory, &FshifterFactory);

+}

+

+void ALfshifter_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)

+{

+    ALeffectProps *props = &effect->Props;

+    switch(param)

+    {

+        case AL_FREQUENCY_SHIFTER_FREQUENCY:

+            if(!(val >= AL_FREQUENCY_SHIFTER_MIN_FREQUENCY && val <= AL_FREQUENCY_SHIFTER_MAX_FREQUENCY))

+                SETERR_RETURN(context, AL_INVALID_VALUE,,"Frequency shifter frequency out of range");

+            props->Fshifter.Frequency = (ALfloat) val;

+            break;

+

+        default:

+            alSetError(context, AL_INVALID_ENUM, "Invalid frequency shifter float property 0x%04x", param);

+    }

+}

+

+void ALfshifter_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)

+{

+    ALfshifter_setParamf(effect, context, param, vals[0]);

+}

+

+void ALfshifter_setParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)

+{

+    ALeffectProps *props = &effect->Props;

+    switch(param)

+    {

+        case AL_FREQUENCY_SHIFTER_LEFT_DIRECTION:

+            if(!(val >= AL_FREQUENCY_SHIFTER_MIN_LEFT_DIRECTION && val <= AL_FREQUENCY_SHIFTER_MAX_LEFT_DIRECTION))

+                SETERR_RETURN(context, AL_INVALID_VALUE,,"Frequency shifter left direction out of range");

+            props->Fshifter.Left_direction = val;

+            break;

+

+        case AL_FREQUENCY_SHIFTER_RIGHT_DIRECTION:

+            if(!(val >= AL_FREQUENCY_SHIFTER_MIN_RIGHT_DIRECTION && val <= AL_FREQUENCY_SHIFTER_MAX_RIGHT_DIRECTION))

+                SETERR_RETURN(context, AL_INVALID_VALUE,,"Frequency shifter right direction out of range");

+            props->Fshifter.Right_direction = val;

+            break;

+

+        default:

+            alSetError(context, AL_INVALID_ENUM, "Invalid frequency shifter integer property 0x%04x", param);

+    }

+}

+void ALfshifter_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)

+{

+    ALfshifter_setParami(effect, context, param, vals[0]);

+}

+

+void ALfshifter_getParami(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)

+{

+    const ALeffectProps *props = &effect->Props;

+    switch(param)

+    {

+        case AL_FREQUENCY_SHIFTER_LEFT_DIRECTION:

+            *val = (ALint)props->Fshifter.Left_direction;

+            break;

+        case AL_FREQUENCY_SHIFTER_RIGHT_DIRECTION:

+            *val = (ALint)props->Fshifter.Right_direction;

+            break;

+        default:

+            alSetError(context, AL_INVALID_ENUM, "Invalid frequency shifter integer property 0x%04x", param);

+    }

+}

+void ALfshifter_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)

+{

+    ALfshifter_getParami(effect, context, param, vals);

+}

+

+void ALfshifter_getParamf(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)

+{

+

+    const ALeffectProps *props = &effect->Props;

+    switch(param)

+    {

+        case AL_FREQUENCY_SHIFTER_FREQUENCY:

+            *val = (ALfloat)props->Fshifter.Frequency;

+            break;

+

+        default:

+            alSetError(context, AL_INVALID_ENUM, "Invalid frequency shifter float property 0x%04x", param);

+    }

+

+}

+

+void ALfshifter_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)

+{

+    ALfshifter_getParamf(effect, context, param, vals);

+}

+

+DEFINE_ALEFFECT_VTABLE(ALfshifter);