decimator_1202.xml

<?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 &lt;steve@plugin.org.uk&gt;"/>
    <meta name="copyright" value="GPL"/>
    <code><![CDATA[
      #include <math.h>
      #include "ladspa-util.h"
    ]]></code>
  </global>

  <plugin label="decimator" id="1202" class="DistortionPlugin">
    <name>Decimator</name>
    <p>Decimates (reduces the effective sample rate), and reduces the bit depth of the input signal, allows non integer values for smooth transitions between clean and lofi signals.</p>

    <callback event="instantiate">
sample_rate = s_rate;
count = 0.0f;
last_out = 0.0f;
    </callback>

    <callback event="run"><![CDATA[
unsigned long pos;
float step, stepr, delta, ratio;
double dummy;

if (bits >= 31.0f || bits < 1.0f) {
	step = 0.0f;
	stepr = 1.0f;
} else {
	step = pow(0.5f, bits - 0.999f);
	stepr = 1/step;
}

if (fs >= sample_rate) {
	ratio = 1.0f;
} else {
	ratio = fs/sample_rate;
}

for (pos = 0; pos < sample_count; pos++) {
	count += ratio;

	if (count >= 1.0f) {
		count -= 1.0f;
		delta = modf((input[pos] + (input[pos]<0?-1.0:1.0)*step*0.5) * stepr, &dummy) * step;
		last_out = input[pos] - delta;
		buffer_write(output[pos], last_out);
	} else {
		buffer_write(output[pos], last_out);
	}
}

plugin_data->last_out = last_out;
plugin_data->count = count;
    ]]></callback>

    <port label="bits" dir="input" type="control" hint="default_maximum">
      <name>Bit depth</name>
      <range min="1" max="24"/>
      <p>The bit depth that the signal will be reduced to.</p>
    </port>

    <port label="fs" dir="input" type="control" hint="sample_rate,default_maximum">
      <name>Sample rate (Hz)</name>
      <range min="0.001" max="1"/>
      <p>The sample rate that the signal will be resampled at.</p>
    </port>

    <port label="input" dir="input" type="audio">
      <name>Input</name>
      <range min="-1.0" max="+1.0"/>
    </port>

    <port label="output" dir="output" type="audio">
      <name>Output</name>
      <range min="-1.0" max="+1.0"/>
    </port>

    <instance-data label="sample_rate" type="long"/>
    <instance-data label="count" type="float"/>
    <instance-data label="last_out" type="LADSPA_Data"/>
  </plugin>
</ladspa>