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/*
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/vumeterdsp.h"
float Vumeterdsp::_w;
float Vumeterdsp::_g;
Vumeterdsp::Vumeterdsp (void) :
_z1 (0),
_z2 (0),
_m (0),
_res (true)
{
}
Vumeterdsp::~Vumeterdsp (void)
{
}
void Vumeterdsp::process (float *p, int n)
{
float z1, z2, m, t1, t2;
z1 = _z1;
z2 = _z2;
m = _res ? 0: _m;
_res = false;
n /= 4;
while (n--)
{
t2 = z2 / 2;
t1 = fabsf (*p++) - t2;
z1 += _w * (t1 - z1);
t1 = fabsf (*p++) - t2;
z1 += _w * (t1 - z1);
t1 = fabsf (*p++) - t2;
z1 += _w * (t1 - z1);
t1 = fabsf (*p++) - t2;
z1 += _w * (t1 - z1);
z2 += 4 * _w * (z1 - z2);
if (z2 > m) m = z2;
}
_z1 = z1;
_z2 = z2 + 1e-10f;
_m = m;
}
float Vumeterdsp::read (void)
{
_res = true;
return _g * _m;
}
void Vumeterdsp::reset ()
{
_z1 = _z2 = _m = .0f;
_res = true;
}
void Vumeterdsp::init (float fsamp)
{
_w = 11.1f / fsamp;
_g = 1.5f * 1.571f;
}
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