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/*
cw_binaural~: a binaural synthesis external for pure data
by David Doukhan - david.doukhan@gmail.com - http://perso.limsi.fr/doukhan
and Anne Sedes - sedes.anne@gmail.com
Copyright (C) 2009-2011 David Doukhan and Anne Sedes
For more details, see CW_binaural~, a binaural synthesis external for Pure Data
David Doukhan and Anne Sedes, PDCON09
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 3 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.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <math.h>
#include "delay.hpp"
#include "logstring.hpp"
Delay* Delay::create(string delay_name, unsigned size)
{
//slog << "creating delay " << delay_name << endl;
// kind of factory design pattern
if (!delay_name.compare("Hermite4"))
return new SCDelay(size);
else if (!delay_name.compare("nodelay"))
return new NoDelay(size);
else if (!delay_name.compare("linear"))
return new BasicInterpolDelay(size);
else if (!delay_name.compare("nofractional"))
return new DummyDelay(size);
else if (!delay_name.compare("6points"))
return new CZDelay(size);
else
{
slog << delay_name << " delay method is not supported" << endl;
throw 0;
}
}
Delay::Delay(unsigned size): _size(size)
{
// FIXME
// ASUMPTION: ITD WILL NEVER BE > SIZE/2
// IT SHOULD BE CHECKED DURING ITD COMPUTATION
_fifo = new float[size];
_fifo_id = 0;
for (unsigned i = 0; i < size; ++i)
_fifo[i] = 0;
_cur_delay = 0;
}
Delay::~Delay()
{
delete [] _fifo;
}
inline void Delay::push_value(float f)
{
_fifo_id = (_fifo_id ? _fifo_id - 1 : _size - 1);
_fifo[_fifo_id] = f;
}
// That ugly macro has been done because of the inneficiency
// of virtual interpolation functions for demanding RT purposes
#define DELAY_PROCESS(code) \
unsigned i; \
_old_delay = _cur_delay; _cur_delay = new_delay; \
float delay = _old_delay; \
const float inc_delay = (_cur_delay - _old_delay) / n; \
\
for (i = 0; i < n; ++i, delay += inc_delay) \
{ \
push_value(input[i]); \
/* compute the id of the current output element \
delayed by and integer value */ \
float floor_delay = floorf(delay); \
\
/* get the current element id in the fifo */ \
unsigned id = _fifo_id + (unsigned) floor_delay; \
if (id >= _size) \
id -= _size; \
\
/* compute the fractional part of the delay */ \
float frac_del = delay - floor_delay; \
\
code \
\
output[i] = res; \
}
void DummyDelay::process(const float* input, float* output, float new_delay, unsigned n)
{
DELAY_PROCESS(
float res = _fifo[id];
)
}
void BasicInterpolDelay::process(const float* input, float* output, float new_delay, unsigned n)
{
DELAY_PROCESS(
unsigned older = (id + 1 == _size ? 0: id + 1);
float res = _fifo[id] * frac_del + (1 - frac_del) * _fifo[older];
)
}
void SCDelay::process(const float* input, float* output, float new_delay, unsigned n)
{
DELAY_PROCESS(
float y0 = _fifo[id];
float y1 = _fifo[(id + 1) % _size];
float y2 = _fifo[(id + 2) % _size];
float y3 = _fifo[(id + 3) % _size];
// 4-point, 3rd-order Hermite (x-form)
float c0 = y1;
float c1 = 0.5 * (y2 - y0);
float c2 = y0 - 2.5 * y1 + 2. * y2 - 0.5 * y3;
float c3 = 0.5 * (y3 - y0) + 1.5 * (y1 - y2);
float res = ((c3 * frac_del + c2) * frac_del + c1) * frac_del + c0;
)
}
void CZDelay::process(const float* input, float* output, float new_delay, unsigned n)
{
// 6 points interpolation
DELAY_PROCESS(
float ym2 = _fifo[id];
float ym1 = _fifo[(id + 1) % _size];
float y0 = _fifo[(id + 2) % _size];
float y1 = _fifo[(id + 3) % _size];
float y2 = _fifo[(id + 4) % _size];
float y3 = _fifo[(id + 5) % _size];
float a0= y0;
float a1= (1./12.)*ym2 - (2./3.)*ym1 + (2./3.)*y1 - (1./12.)*y2;
float a2= (-1./24.)*ym2 + (2./3.)*ym1 - (5./4.)*y0 + (2./3.)*y1 - (1./24.)*y2;
float a3= (-3./8.)*ym2 + (13./8.)*ym1 - (35./12.)*y0 + (11./4.)*y1 - (11./8.)*y2 + (7./24.)*y3;
float a4= (13./24.)*ym2 - (8./3.)*ym1 + (21./4.)*y0 - (31./6.)*y1 + (61./24.)*y2 - (1./2.)*y3;
float a5= (-5./24.)*ym2 + (25./24.)*ym1 - (25./12.)*y0 + (25./12.)*y1 - (25./24.)*y2 + (5./24.)*y3;
float res = a0 + frac_del * (a1 + frac_del * (a2 + frac_del * (a3 + frac_del * (a4 + frac_del * a5))));
)
}
void NoDelay::process(const float *input, float *output, float new_delay, unsigned n)
{
for (unsigned i = 0; i < n; ++i)
output[i] = input[i];
}
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