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<?xml version="1.0" ?>
<!DOCTYPE ladspa SYSTEM "ladspa-swh.dtd">
<?xml-stylesheet href="ladspa.css" type="text/css" ?>
<ladspa>
<global>
<meta name="maker" value="Steve Harris <steve@plugin.org.uk>"/>
<meta name="copyright" value="GPL"/>
<meta name="properties" value="HARD_RT_CAPABLE"/>
<code>
#include "ladspa-util.h"
#define COMB_SIZE 0x4000
#define COMB_MASK 0x3FFF
</code>
</global>
<plugin label="combSplitter" id="1411" class="CombPlugin">
<name>Comb Splitter</name>
<p>Divides the input up into two parts with frequency peaks at f Hz intervals, skewed by f/2 Hz between the two outputs. Mixing the two outputs will get you exactly the input signal.</p>
<p>I generally use this trick to divide up an input signal, process the two halves differently, then mix them again. It sounds pretty funky.</p>
<callback event="instantiate">
sample_rate = s_rate;
comb_tbl = malloc(sizeof(LADSPA_Data) * COMB_SIZE);
comb_pos = 0;
last_offset = 1000;
</callback>
<callback event="activate">
int i;
for (i = 0; i < COMB_SIZE; i++) {
comb_tbl[i] = 0;
}
comb_pos = 0;
last_offset = 1000;
</callback>
<callback event="cleanup">
free(plugin_data->comb_tbl);
</callback>
<callback event="run"><![CDATA[
float offset;
int data_pos;
unsigned long pos;
float xf, xf_step, d_pos, fr, interp, in;
offset = sample_rate / freq;
offset = f_clamp(offset, 0, COMB_SIZE - 1);
xf_step = 1.0f / (float)sample_count;
xf = 0.0f;
for (pos = 0; pos < sample_count; pos++) {
xf += xf_step;
d_pos = comb_pos - LIN_INTERP(xf, last_offset, offset);
data_pos = f_trunc(d_pos);
fr = d_pos - data_pos;
interp = cube_interp(fr, comb_tbl[(data_pos - 1) & COMB_MASK], comb_tbl[data_pos & COMB_MASK], comb_tbl[(data_pos + 1) & COMB_MASK], comb_tbl[(data_pos + 2) & COMB_MASK]);
in = input[pos];
comb_tbl[comb_pos] = in;
buffer_write(out1[pos], (in + interp) * 0.5f);
buffer_write(out2[pos], (in - interp) * 0.5f);
comb_pos = (comb_pos + 1) & COMB_MASK;
}
plugin_data->comb_pos = comb_pos;
plugin_data->last_offset = offset;
]]></callback>
<port label="freq" dir="input" type="control" hint="default_low">
<name>Band separation (Hz)</name>
<range min="16" max="640"/>
<p>The distance between the frequency peaks.</p>
</port>
<port label="input" dir="input" type="audio">
<name>Input</name>
</port>
<port label="out1" dir="output" type="audio">
<name>Output 1</name>
<p>The sum output.</p>
</port>
<port label="out2" dir="output" type="audio">
<name>Output 2</name>
<p>The difference output.</p>
</port>
<instance-data label="comb_tbl" type="LADSPA_Data *"/>
<instance-data label="comb_pos" type="long"/>
<instance-data label="sample_rate" type="long"/>
<instance-data label="last_offset" type="float"/>
</plugin>
</ladspa>
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