fad_delay_1192.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>
#include "ladspa-util.h"

#define BASE_BUFFER 8 // Base buffer length (s)
		</code>
	</global>

	<plugin label="fadDelay" id="1192" class="DelayPlugin">
		<name>Fractionally Addressed Delay Line</name>
		<p>A fixed ring buffer delay implementation. Has different dynamics to a normal delay, more suitable for certain things.</p>
		<p>Changes in delay length are generally more pleasing, but delays >2s long have reduced sound quality.</p>

		<callback event="instantiate"><![CDATA[
			unsigned int min_bs;

			sample_rate = s_rate;
			min_bs = BASE_BUFFER * s_rate;
			for (buffer_size = 4096; buffer_size < min_bs;
			     buffer_size *= 2);
			buffer = calloc(buffer_size, sizeof(LADSPA_Data));
			buffer_mask = buffer_size - 1;
			phase = 0;
			last_phase = 0;
			last_in = 0.0f;
		]]></callback>

		<callback event="activate">
			int i;

			for (i = 0; i &lt; buffer_size; i++) {
				buffer[i] = 0;
			}
			phase = 0;
			last_phase = 0;
			last_in = 0.0f;
		</callback>

		<callback event="cleanup">
			free(plugin_data->buffer);
		</callback>

		<callback event="run"><![CDATA[
long int pos;
float increment = (float)buffer_size / ((float)sample_rate *
					f_max(fabs(delay), 0.01));
float lin_int, lin_inc;
int track;
int fph;
LADSPA_Data out;
const float fb = DB_CO(fb_db);

for (pos = 0; pos < sample_count; pos++) {
	fph = f_round(floor(phase));
	last_phase = fph;
	lin_int = phase - (float)fph;
	out = LIN_INTERP(lin_int, buffer[(fph+1) & buffer_mask],
	 buffer[(fph+2) & buffer_mask]);
	phase += increment;
	lin_inc = 1.0f / (floor(phase) - last_phase + 1);
	lin_inc = lin_inc > 1.0f ? 1.0f : lin_inc;
	lin_int = 0.0f;
	for (track = last_phase; track < phase; track++) {
		lin_int += lin_inc;
		buffer[track % buffer_size] = out * fb +
		 LIN_INTERP(lin_int, last_in, input[pos]);
	}
	last_in = input[pos];
	buffer_write(output[pos], out);
	if (phase >= buffer_size) {
		phase -= buffer_size;
	}
}

// Store current phase in instance
plugin_data->phase = phase;
plugin_data->last_phase = last_phase;
plugin_data->last_in = last_in;
		]]></callback>

		<port label="delay" dir="input" type="control" hint="default_1">
			<name>Delay (seconds)</name>
			<p>The neutral delay time is 2 seconds. Times above 2 seconds will have reduced quality and times below will have increased CPU usage.</p>
			<range min="0.1" max="10"/>
		</port>

		<port label="fb_db" dir="input" type="control" hint="default_0">
			<name>Feedback (dB)</name>
			<range min="-70" max="0"/>
		</port>

		<port label="input" dir="input" type="audio">
			<name>Input</name>
		</port>

		<port label="output" dir="output" type="audio">
			<name>Output</name>
		</port>

		<instance-data label="buffer" type="LADSPA_Data *"/>
		<instance-data label="phase" type="float"/>
		<instance-data label="last_phase" type="int"/>
		<instance-data label="last_in" type="LADSPA_Data"/>
		<instance-data label="buffer_size" type="unsigned long"/>
		<instance-data label="buffer_mask" type="unsigned long"/>
		<instance-data label="sample_rate" type="long"/>
	</plugin>
</ladspa>