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/* -*- Mode: C ; c-basic-offset: 2 -*- */
/*****************************************************************************
*
* Copyright (C) 2007 Nedko Arnaudov <nedko@arnaudov.name>
* Copyright (C) Josh Green <jgreen@users.sourceforge.net>
* Copyright (C) Achim Settelmeier <vocoder@m1.sirlab.de>
*
* 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; version 2 of the License
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
*****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <assert.h>
#include <lv2.h>
#define MAX_BANDS 16
#define AMPLIFIER 16.0
struct bandpass
{
float c, f, att;
float freq;
float low1, low2;
float mid1, mid2;
float high1, high2;
float y;
};
struct bands_out
{
float decay;
float oldval;
float level; /* 0.0 - 1.0 level of this output band */
};
const float decay_table[] =
{
1/100.0,
1/100.0, 1/100.0, 1/100.0,
1/125.0, 1/125.0, 1/125.0,
1/166.0, 1/166.0, 1/166.0,
1/200.0, 1/200.0, 1/200.0,
1/250.0, 1/250.0, 1/250.0
};
/* The port numbers for the plugin: */
#define PORT_FORMANT 0
#define PORT_CARRIER 1
#define PORT_OUTPUT 2
#define CTRL_BANDCOUNT 3
#define CTRL_BAND1LVL 4
#define PORT_COUNT 4 + MAX_BANDS
/* useful macros */
#undef CLAMP
#define CLAMP(x, low, high) (((x) > (high)) ? (high) : (((x) < (low)) ? (low) : (x)))
/* Instance data for the vocoder plugin */
struct vocoder
{
float sample_rate;
int num_bands; /* current number of bands */
float mainvol; /* main volume */
struct bandpass bands_formant[MAX_BANDS]; /* one structure per band */
struct bandpass bands_carrier[MAX_BANDS]; /* one structure per band */
struct bands_out bands_out[MAX_BANDS]; /* one structure per band */
/* Ports */
float * portFormant; /* Formant signal port data location */
float * portCarrier; /* Carrier signal port data location */
float * portOutput; /* Output audio port data location */
float * ctrlBandCount; /* Band count control */
float * ctrlBandLevels[MAX_BANDS]; /* level controls for each band */
};
void
vocoder_do_bandpasses(
struct bandpass * bands,
float sample,
struct vocoder * vocoder_ptr)
{
int i;
for (i=0; i < vocoder_ptr->num_bands; i++)
{
bands[i].high1 = sample - bands[i].f * bands[i].mid1 - bands[i].low1;
bands[i].mid1 += bands[i].high1 * bands[i].c;
bands[i].low1 += bands[i].mid1;
bands[i].high2 = bands[i].low1 - bands[i].f * bands[i].mid2 - bands[i].low2;
bands[i].mid2 += bands[i].high2 * bands[i].c;
bands[i].low2 += bands[i].mid2;
bands[i].y = bands[i].high2 * bands[i].att;
}
}
static
LV2_Handle
instantiate(
const LV2_Descriptor * descriptor,
double sample_rate,
const char * bundle_path,
const LV2_Feature * const * host_features)
{
struct vocoder * vocoder_ptr;
vocoder_ptr = malloc(sizeof(struct vocoder));
if (vocoder_ptr == NULL)
{
return NULL;
}
vocoder_ptr->sample_rate = sample_rate;
vocoder_ptr->num_bands = -1;
return (LV2_Handle)vocoder_ptr;
}
#define vocoder_ptr ((struct vocoder *)lv2instance)
/* Initialise and activate a plugin instance. */
static
void
activate(
LV2_Handle lv2instance)
{
int i;
vocoder_ptr->mainvol = 1.0 * AMPLIFIER;
for (i = 0; i < MAX_BANDS; i++)
{
vocoder_ptr->bands_out[i].oldval = 0.0;
}
}
static
void
deactivate(
LV2_Handle lv2instance)
{
}
/* Connect a port to a data location. */
static
void
connect_port(
LV2_Handle lv2instance,
uint32_t port,
void * data)
{
switch (port)
{
case PORT_FORMANT: /* formant port */
vocoder_ptr->portFormant = data;
return;
case PORT_CARRIER: /* carrier port */
vocoder_ptr->portCarrier = data;
return;
case PORT_OUTPUT: /* output port */
vocoder_ptr->portOutput = data;
return;
case CTRL_BANDCOUNT: /* band count control */
vocoder_ptr->ctrlBandCount = data;
return;
}
/* a band level control? */
if (port >= CTRL_BAND1LVL && port < CTRL_BAND1LVL + MAX_BANDS)
{
vocoder_ptr->ctrlBandLevels[port - CTRL_BAND1LVL] = data;
return;
}
assert(0);
}
/* Run a vocoder instance for a block of SampleCount samples. */
static
void
run(
LV2_Handle lv2instance,
uint32_t sample_count)
{
int i, j, numbands;
float a;
float x, c;
numbands = (int)(*vocoder_ptr->ctrlBandCount);
if (numbands < 1 || numbands > MAX_BANDS) numbands = MAX_BANDS;
/* initialize bandpass information if num_bands control has changed,
or on first run */
if (vocoder_ptr->num_bands != numbands)
{
vocoder_ptr->num_bands = numbands;
for(i=0; i < numbands; i++)
{
memset(&vocoder_ptr->bands_formant[i], 0, sizeof(struct bandpass));
a = 16.0 * i/(double)numbands; // stretch existing bands
if (a < 4.0)
vocoder_ptr->bands_formant[i].freq = 150 + 420 * a / 4.0;
else
vocoder_ptr->bands_formant[i].freq = 600 * pow (1.23, a - 4.0);
c = vocoder_ptr->bands_formant[i].freq * 2 * M_PI / vocoder_ptr->sample_rate;
vocoder_ptr->bands_formant[i].c = c * c;
vocoder_ptr->bands_formant[i].f = 0.4/c;
vocoder_ptr->bands_formant[i].att =
1/(6.0 + ((exp (vocoder_ptr->bands_formant[i].freq
/ vocoder_ptr->sample_rate) - 1) * 10));
memcpy(&vocoder_ptr->bands_carrier[i],
&vocoder_ptr->bands_formant[i], sizeof(struct bandpass));
vocoder_ptr->bands_out[i].decay = decay_table[(int)a];
vocoder_ptr->bands_out[i].level =
CLAMP (*vocoder_ptr->ctrlBandLevels[i], 0.0, 1.0);
}
}
else /* get current values of band level controls */
{
for (i = 0; i < numbands; i++)
vocoder_ptr->bands_out[i].level = CLAMP (*vocoder_ptr->ctrlBandLevels[i],
0.0, 1.0);
}
for (i=0; i < sample_count; i++)
{
vocoder_do_bandpasses(vocoder_ptr->bands_carrier, vocoder_ptr->portCarrier[i], vocoder_ptr);
vocoder_do_bandpasses(vocoder_ptr->bands_formant, vocoder_ptr->portFormant[i], vocoder_ptr);
vocoder_ptr->portOutput[i] = 0.0;
for (j=0; j < numbands; j++)
{
vocoder_ptr->bands_out[j].oldval = vocoder_ptr->bands_out[j].oldval
+ (fabs (vocoder_ptr->bands_formant[j].y)
- vocoder_ptr->bands_out[j].oldval)
* vocoder_ptr->bands_out[j].decay;
x = vocoder_ptr->bands_carrier[j].y * vocoder_ptr->bands_out[j].oldval;
vocoder_ptr->portOutput[i] += x * vocoder_ptr->bands_out[j].level;
}
vocoder_ptr->portOutput[i] *= vocoder_ptr->mainvol;
}
}
static
void
cleanup(LV2_Handle lv2instance)
{
free(vocoder_ptr);
}
static LV2_Descriptor g_lv2descriptor =
{
.URI = "http://home.gna.org/lv2vocoder/1",
.instantiate = instantiate,
.connect_port = connect_port,
.activate = activate,
.deactivate = deactivate,
.run = run,
.cleanup = cleanup,
};
const LV2_Descriptor *
lv2_descriptor(uint32_t index)
{
if (index == 0)
{
return &g_lv2descriptor;
}
return NULL;
}
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