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git-svn-id: https://lmms.svn.sf.net/svnroot/lmms/branches/lmms-mv@726 0778d3d1-df1d-0410-868b-ea421aaaa00d
149 lines
2.8 KiB
C++
149 lines
2.8 KiB
C++
/*
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Clip.cc
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Copyright 2003-7 Tim Goetze <tim@quitte.de>
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http://quitte.de/dsp/
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simple oversampled hard clipper
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*/
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/*
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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02111-1307, USA or point your web browser to http://www.gnu.org.
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*/
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#include "basics.h"
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#include "Clip.h"
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#include "Descriptor.h"
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void
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Clip::init()
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{
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gain = 1;
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threshold[0] = -.9;
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threshold[1] = +.9;
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/* going a bit lower than nominal with fc */
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double f = .5 * M_PI / OVERSAMPLE;
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/* construct the upsampler filter kernel */
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DSP::sinc (f, up.c, FIR_SIZE);
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DSP::kaiser<DSP::apply_window> (up.c, FIR_SIZE, 6.4);
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/* copy upsampler filter kernel for downsampler, make sum */
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double s = 0;
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for (int i = 0; i < up.n; ++i)
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down.c[i] = up.c[i],
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s += up.c[i];
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/* scale downsampler kernel for unity gain */
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s = 1 / s;
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for (int i = 0; i < down.n; ++i)
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down.c[i] *= s;
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/* scale upsampler kernel for unity gain */
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s *= OVERSAMPLE;
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for (int i = 0; i < up.n; ++i)
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up.c[i] *= s;
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}
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inline d_sample
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Clip::clip (d_sample a)
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{
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if (a < threshold[0])
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return threshold[0];
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if (a > threshold[1])
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return threshold[1];
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return a;
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}
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template <sample_func_t F>
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void
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Clip::one_cycle (int frames)
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{
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d_sample * s = ports[0];
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double g = getport (1);
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double gf;
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if (g == gain_db)
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gf = 1;
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else
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{
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gain_db = g;
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d_sample g = DSP::db2lin (gain_db);
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gf = pow (g / gain, 1 / (double) frames);
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}
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d_sample * d = ports[2];
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*ports[3] = OVERSAMPLE;
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for (int i = 0; i < frames; ++i)
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{
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register d_sample a = gain * s[i];
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a = down.process (clip (up.upsample (a)));
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for (int o = 1; o < OVERSAMPLE; ++o)
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down.store (clip (up.pad (o)));
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F (d, i, a, adding_gain);
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gain *= gf;
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}
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}
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/* //////////////////////////////////////////////////////////////////////// */
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PortInfo
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Clip::port_info [] =
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{
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{
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"in",
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INPUT | AUDIO,
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{BOUNDED, -1, 1}
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}, {
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"gain (dB)",
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INPUT | CONTROL,
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{BOUNDED | DEFAULT_1, -72, 72}
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}, {
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"out",
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OUTPUT | AUDIO,
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{0}
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}, {
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"latency",
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OUTPUT | CONTROL,
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{0}
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}
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};
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template <> void
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Descriptor<Clip>::setup()
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{
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UniqueID = 1771;
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Label = "Clip";
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Properties = HARD_RT;
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Name = CAPS "Clip - Hard clipper, 8x oversampled";
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Maker = "Tim Goetze <tim@quitte.de>";
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Copyright = "GPL, 2003-7";
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/* fill port info and vtable */
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autogen();
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}
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