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/*
Copyright (C) 2001-2002 Stefan Westerfeld
stefan@space.twc.de
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
#include <math.h>
#include <arts/debug.h>
#include <arts/fft.h>
#include <arts/stdsynthmodule.h>
#include <arts/connect.h>
#include "artsmoduleseffects.h"
#include <stdio.h>
#include <stdlib.h>
#include <kglobal.h>
#include <klocale.h>
using namespace std;
using namespace Arts;
static inline bool odd(int x) { return ((x & 1) == 1); }
/* returns a blackman window: x is supposed to be in the interval [0..1] */
static inline float blackmanWindow(float x)
{
if(x < 0) return 0;
if(x > 1) return 0;
return 0.42-0.5*cos(M_PI*x*2)+0.08*cos(4*M_PI*x);
}
void firapprox(double *filter, int filtersize, vector<GraphPoint>& points)
{
assert((filtersize >= 3) && odd(filtersize));
int fft_size = 8;
while(fft_size/2 < filtersize)
fft_size *= 2;
vector<GraphPoint>::iterator pi = points.begin();
float lfreq=-2, lval=1.0, rfreq=-1, rval=1.0;
float *re = (float*) malloc(fft_size * sizeof(float));
for(int i=0;i<fft_size/2;i++)
{
float freq = float(i)/float(fft_size/2);
while(freq > rfreq && pi != points.end())
{
lfreq = rfreq; rfreq = pi->x;
lval = rval; rval = pi->y;
pi++;
}
float pos = (freq-lfreq)/(rfreq-lfreq);
float val = lval*(1.0-pos) + rval*pos;
//printf("%f %f\n",freq,val);
re[i] = re[fft_size-1-i] = val;
}
float *filter_re = (float*) malloc(fft_size * sizeof(float));
float *filter_im = (float*) malloc(fft_size * sizeof(float));
arts_fft_float (fft_size, 1, re, 0, filter_re, filter_im);
for(int i=0;i<filtersize;i++)
{
filter[i] = filter_re[(i+fft_size-filtersize/2) & (fft_size-1)]
* blackmanWindow(float(i+1)/float(filtersize+1));
}
free(re);
free(filter_re);
free(filter_im);
}
namespace Arts {
class Synth_STEREO_FIR_EQUALIZER_impl
: virtual public Synth_STEREO_FIR_EQUALIZER_skel,
virtual public StdSynthModule
{
vector<GraphPoint> _frequencies;
long _taps;
unsigned long bpos;
double filter[256];
float lbuffer[256];
float rbuffer[256];
public:
Synth_STEREO_FIR_EQUALIZER_impl()
{
_frequencies.push_back(GraphPoint(0.0,1.0));
_frequencies.push_back(GraphPoint(1.0,1.0));
_taps = 3;
for(bpos = 0; bpos < 256; bpos++)
lbuffer[bpos] = rbuffer[bpos] = 0.0;
calcFilter();
}
vector<GraphPoint> *frequencies() {
return new vector<GraphPoint>(_frequencies);
}
void frequencies(const vector<GraphPoint>& newFrequencies)
{
_frequencies = newFrequencies;
calcFilter();
}
long taps()
{
return _taps;
}
void taps(long newTaps)
{
arts_return_if_fail(newTaps >= 3 && newTaps <= 255);
if(!odd(newTaps))
newTaps++;
_taps = newTaps;
calcFilter();
}
void calcFilter()
{
firapprox(filter, _taps, _frequencies);
}
void calculateBlock(unsigned long samples)
{
for(unsigned i=0;i<samples;i++)
{
double lval = 0.0;
double rval = 0.0;
lbuffer[bpos & 255] = inleft[i];
rbuffer[bpos & 255] = inright[i];
for(int j=0;j<_taps;j++)
{
lval += lbuffer[(bpos-j) & 255] * filter[j];
rval += rbuffer[(bpos-j) & 255] * filter[j];
}
outleft[i] = lval;
outright[i] = rval;
bpos++;
}
}
};
REGISTER_IMPLEMENTATION(Synth_STEREO_FIR_EQUALIZER_impl);
class StereoFirEqualizerGuiFactory_impl : public StereoFirEqualizerGuiFactory_skel
{
public:
Widget createGui(Object equalizer);
};
REGISTER_IMPLEMENTATION(StereoFirEqualizerGuiFactory_impl);
}
Widget StereoFirEqualizerGuiFactory_impl::createGui(Object object)
{
KGlobal::locale()->insertCatalogue( "artsmodules" );
arts_return_val_if_fail(!object.isNull(), Arts::Widget::null());
Synth_STEREO_FIR_EQUALIZER equalizer = DynamicCast(object);
arts_return_val_if_fail(!equalizer.isNull(), Arts::Widget::null());
VBox vbox;
vbox.show();
Graph g;
g.parent(vbox);
g.width(400);
g.height(230);
g.caption(i18n("a graph").utf8().data());
g.minx(0.0);
g.maxx(1.0);
g.miny(0.0);
g.maxy(1.0);
g.show();
GraphLine gline;
gline.graph(g);
vector<GraphPoint> *points = equalizer.frequencies();
gline.points(*points);
delete points;
gline.color("red");
gline.editable(true);
connect(gline,"points_changed", equalizer, "frequencies");
g._addChild(gline,"gline");
SpinBox spinbox;
spinbox.caption(i18n("channels").utf8().data());
spinbox.min(3); spinbox.max(255);
spinbox.value(equalizer.taps());
spinbox.parent(vbox);
spinbox.show();
connect(spinbox,"value_changed", equalizer, "taps");
vbox._addChild(spinbox,"spinbox");
vbox._addChild(g,"g");
return vbox;
}
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