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livetrax/libs/ardour/iec2ppmdsp.cc

101 lines
2.1 KiB
C++

/*
Copyright (C) 2012 Fons Adriaensen <fons@linuxaudio.org>
Adopted for Ardour 2013 by Robin Gareus <robin@gareus.org>
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.
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <math.h>
#include "ardour/iec2ppmdsp.h"
float Iec2ppmdsp::_w1;
float Iec2ppmdsp::_w2;
float Iec2ppmdsp::_w3;
float Iec2ppmdsp::_g;
Iec2ppmdsp::Iec2ppmdsp (void) :
_z1 (0),
_z2 (0),
_m (0),
_res (true)
{
}
Iec2ppmdsp::~Iec2ppmdsp (void)
{
}
void Iec2ppmdsp::process (float const *p, int n)
{
float z1, z2, m, t;
z1 = _z1 > 20 ? 20 : (_z1 < 0 ? 0 : _z1);
z2 = _z2 > 20 ? 20 : (_z2 < 0 ? 0 : _z2);
m = _res ? 0: _m;
_res = false;
n /= 4;
while (n--)
{
z1 *= _w3;
z2 *= _w3;
t = fabsf (*p++);
if (t > z1) z1 += _w1 * (t - z1);
if (t > z2) z2 += _w2 * (t - z2);
t = fabsf (*p++);
if (t > z1) z1 += _w1 * (t - z1);
if (t > z2) z2 += _w2 * (t - z2);
t = fabsf (*p++);
if (t > z1) z1 += _w1 * (t - z1);
if (t > z2) z2 += _w2 * (t - z2);
t = fabsf (*p++);
if (t > z1) z1 += _w1 * (t - z1);
if (t > z2) z2 += _w2 * (t - z2);
t = z1 + z2;
if (t > m) m = t;
}
_z1 = z1 + 1e-10f;
_z2 = z2 + 1e-10f;
_m = m;
}
float Iec2ppmdsp::read (void)
{
_res = true;
return _g * _m;
}
void Iec2ppmdsp::reset ()
{
_z1 = _z2 = _m = .0f;
_res = true;
}
void Iec2ppmdsp::init (float fsamp)
{
_w1 = 200.0f / fsamp;
_w2 = 860.0f / fsamp;
_w3 = 1.0f - 4.0f / fsamp;
_g = 0.5141f;
}
/* vi:set ts=8 sts=8 sw=4: */