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livetrax/libs/plugins/a-comp.lv2/a-comp.c

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2016-07-02 21:21:44 -04:00
/* a-comp
* Copyright (C) 2016 Damien Zammit <damien@zamaudio.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*/
#include <math.h>
#include <stdlib.h>
#include "lv2/lv2plug.in/ns/lv2core/lv2.h"
#define ACOMP_URI "urn:ardour:a-comp"
typedef enum {
ACOMP_INPUT0 = 0,
ACOMP_INPUT1,
ACOMP_OUTPUT,
ACOMP_ATTACK,
ACOMP_RELEASE,
ACOMP_KNEE,
ACOMP_RATIO,
ACOMP_THRESHOLD,
ACOMP_MAKEUP,
ACOMP_GAINR,
ACOMP_OUTLEVEL,
ACOMP_SIDECHAIN,
} PortIndex;
typedef struct {
float* input0;
float* input1;
float* output;
float* attack;
float* release;
float* knee;
float* ratio;
float* thresdb;
float* makeup;
float* gainr;
float* outlevel;
float* sidechain;
float srate;
float old_yl;
float old_y1;
float old_yg;
} AComp;
static LV2_Handle
instantiate(const LV2_Descriptor* descriptor,
double rate,
const char* bundle_path,
const LV2_Feature* const* features)
{
AComp* acomp = (AComp*)malloc(sizeof(AComp));
acomp->srate = rate;
acomp->old_yl=acomp->old_y1=acomp->old_yg=0.f;
return (LV2_Handle)acomp;
}
static void
connect_port(LV2_Handle instance,
uint32_t port,
void* data)
{
AComp* acomp = (AComp*)instance;
switch ((PortIndex)port) {
case ACOMP_ATTACK:
acomp->attack = (float*)data;
break;
case ACOMP_RELEASE:
acomp->release = (float*)data;
break;
case ACOMP_KNEE:
acomp->knee = (float*)data;
break;
case ACOMP_RATIO:
acomp->ratio = (float*)data;
break;
case ACOMP_THRESHOLD:
acomp->thresdb = (float*)data;
break;
case ACOMP_MAKEUP:
acomp->makeup = (float*)data;
break;
case ACOMP_GAINR:
acomp->gainr = (float*)data;
break;
case ACOMP_OUTLEVEL:
acomp->outlevel = (float*)data;
break;
case ACOMP_SIDECHAIN:
acomp->sidechain = (float*)data;
break;
case ACOMP_INPUT0:
acomp->input0 = (float*)data;
break;
case ACOMP_INPUT1:
acomp->input1 = (float*)data;
break;
case ACOMP_OUTPUT:
acomp->output = (float*)data;
break;
}
}
// Force already-denormal float value to zero
static inline float
sanitize_denormal(float value) {
if (!isnormal(value)) {
value = 0.f;
}
return value;
}
static inline float
from_dB(float gdb) {
return (exp(gdb/20.f*log(10.f)));
}
static inline float
to_dB(float g) {
return (20.f*log10(g));
}
static void
activate(LV2_Handle instance)
{
AComp* acomp = (AComp*)instance;
*(acomp->gainr) = 0.0f;
*(acomp->outlevel) = -45.0f;
acomp->old_yl=acomp->old_y1=acomp->old_yg=0.f;
}
static void
run(LV2_Handle instance, uint32_t n_samples)
{
AComp* acomp = (AComp*)instance;
const float* const input0 = acomp->input0;
const float* const input1 = acomp->input1;
float* const output = acomp->output;
float srate = acomp->srate;
float width = (6.f * *(acomp->knee)) + 0.01;
float cdb=0.f;
float attack_coeff = exp(-1000.f/(*(acomp->attack) * srate));
float release_coeff = exp(-1000.f/(*(acomp->release) * srate));
float max = 0.f;
float lgaininp = 0.f;
float Lgain = 1.f;
float Lxg, Lxl, Lyg, Lyl, Ly1;
int usesidechain = (*(acomp->sidechain) < 0.5) ? 0 : 1;
uint32_t i;
float ingain;
float in0;
float in1;
float ratio = *(acomp->ratio);
float thresdb = *(acomp->thresdb);
for (i = 0; i < n_samples; i++) {
in0 = input0[i];
in1 = input1[i];
ingain = usesidechain ? in1 : in0;
Lyg = 0.f;
Lxg = (ingain==0.f) ? -160.f : to_dB(fabs(ingain));
Lxg = sanitize_denormal(Lxg);
Lyg = Lxg + (1.f/ratio-1.f)*(Lxg-thresdb+width/2.f)*(Lxg-thresdb+width/2.f)/(2.f*width);
if (2.f*(Lxg-thresdb) < -width) {
Lyg = Lxg;
} else {
Lyg = thresdb + (Lxg-thresdb)/ratio;
Lyg = sanitize_denormal(Lyg);
}
Lxl = Lxg - Lyg;
acomp->old_y1 = sanitize_denormal(acomp->old_y1);
acomp->old_yl = sanitize_denormal(acomp->old_yl);
Ly1 = fmaxf(Lxl, release_coeff * acomp->old_y1+(1.f-release_coeff)*Lxl);
Lyl = attack_coeff * acomp->old_yl+(1.f-attack_coeff)*Ly1;
Ly1 = sanitize_denormal(Ly1);
Lyl = sanitize_denormal(Lyl);
cdb = -Lyl;
Lgain = from_dB(cdb);
*(acomp->gainr) = Lyl;
lgaininp = in0 * Lgain;
output[i] = lgaininp * from_dB(*(acomp->makeup));
max = (fabsf(output[i]) > max) ? fabsf(output[i]) : sanitize_denormal(max);
acomp->old_yl = Lyl;
acomp->old_y1 = Ly1;
acomp->old_yg = Lyg;
}
*(acomp->outlevel) = (max == 0.f) ? -45.f : to_dB(max);
}
static void
deactivate(LV2_Handle instance)
{
}
static void
cleanup(LV2_Handle instance)
{
free(instance);
}
static const void*
extension_data(const char* uri)
{
return NULL;
}
static const LV2_Descriptor descriptor = {
ACOMP_URI,
instantiate,
connect_port,
activate,
run,
deactivate,
cleanup,
extension_data
};
LV2_SYMBOL_EXPORT
const LV2_Descriptor*
lv2_descriptor(uint32_t index)
{
switch (index) {
case 0:
return &descriptor;
default:
return NULL;
}
}