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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="Lukas Pirl <lv2@lukas-pirl.de>"/>
<meta name="copyright" value="GPL"/>
<meta name="properties" value="HARD_RT_CAPABLE"/>
<code><![CDATA[
#include "ladspa-util.h"
#define MAX_OFFSET 24000
#define BUFFER_LEN (MAX_OFFSET*2 + 1)
#define BUFFER_POS(a) (((a) + BUFFER_LEN) % BUFFER_LEN)
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))
]]></code>
</global>
<plugin label="offset" id="1916" class="UtilityPlugin">
<name>Offset, sample-based</name>
<p>Intended to be used to eliminate offset between tracks (e.g. single sound source simultaneously recorded from different distances).</p>
<callback event="instantiate"><![CDATA[
buffer = calloc(BUFFER_LEN, sizeof(LADSPA_Data));
]]></callback>
<callback event="activate"><![CDATA[
memset(buffer, 0, BUFFER_LEN * sizeof(LADSPA_Data));
plugin_data->buffer_w_pos = 0;
plugin_data->last_offset = 0;
]]></callback>
<callback event="cleanup"><![CDATA[
free(plugin_data->buffer);
]]></callback>
<callback event="run"><![CDATA[
long buffer_r_pos, offset_delta, i;
if (automatable > 0) {
// report the maximum offset as latency to the host
*(plugin_data->latency) = MAX_OFFSET;
// and delay by the maximum offset by default
// (results in no audible offset)
buffer_r_pos = BUFFER_POS(buffer_w_pos - MAX_OFFSET);
// apply user-configured offset (results in the desired offset):
buffer_r_pos = BUFFER_POS(buffer_r_pos + (long)offset);
} else {
// report the currently required latency
// (the LV2 specification does not allow a negative latency)
*(plugin_data->latency) = MAX((long)offset, 0);
// if delaying, apply the configured offset
// (otherwise we rely on the host's latency compensation)
buffer_r_pos = BUFFER_POS(buffer_w_pos + MIN((long)offset, 0));
}
// if the offset increased, zero the buffer accordingly
offset_delta = (long)offset - last_offset;
for (; offset_delta>0; offset_delta--) {
buffer[BUFFER_POS(buffer_r_pos - offset_delta)] = 0.0f;
}
for (i=0; i<sample_count; i++) {
buffer[buffer_w_pos] = input[i];
buffer_w_pos = BUFFER_POS(buffer_w_pos + 1);
buffer_write(output[i], buffer[buffer_r_pos]);
buffer[buffer_r_pos] = 0.0f;
buffer_r_pos = BUFFER_POS(buffer_r_pos + 1);
}
plugin_data->buffer_w_pos = buffer_w_pos;
plugin_data->last_offset = (long)offset;
]]></callback>
<port label="offset" dir="input" type="control" hint="default_0,causes_artifacts">
<name>offset (in samples)</name>
<p>If positive, input will be played earlier; if negative, it's a delay.</p>
<range min="-24000" max="24000" steps="48001"/>
</port>
<port label="automatable" dir="input" type="control" hint="default_0,toggled">
<name>automatable (possibly adds playback delay)</name>
<p>Turn this off if the offset does not change when rolling. Otherwise, the required buffer possibly adds a playback delay.</p>
</port>
<port label="input" dir="input" type="audio">
<name>Input</name>
</port>
<port label="output" dir="output" type="audio">
<name>Output</name>
</port>
<port label="latency" dir="output" type="control">
<name>latency</name>
</port>
<!-- this is a ring buffer -->
<instance-data label="buffer" type="LADSPA_Data *" />
<instance-data label="buffer_w_pos" type="long" />
<instance-data label="last_offset" type="long" />
</plugin>
</ladspa>
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