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<refentry id="sndloop">
<indexterm id="Indexsndloop"><primary>sndloop</primary></indexterm>
<refentryinfo><title>Signal Generators:Sample Playback</title></refentryinfo>
<refmeta>
<refentrytitle>sndloop</refentrytitle>
</refmeta>
<refnamediv>
<refname>sndloop</refname>
<refpurpose>
A sound looper with pitch control.
</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<para>
This opcode records input audio and plays it back in a loop with user-defined
duration and crossfade time. It also allows the pitch of the loop to be controlled,
including reversed playback.
</para>
</refsect1>
<refsect1>
<title>Syntax</title>
<synopsis>asig, krec <command>sndloop</command> ain, kpitch, ktrig, idur, ifad</synopsis>
</refsect1>
<refsect1>
<title>Initialization</title>
<para>
<emphasis>idur </emphasis> -- loop duration in seconds
</para>
<para>
<emphasis>ifad </emphasis> -- crossfade duration in seconds
</para>
</refsect1>
<refsect1>
<title>Performance</title>
<para>
<emphasis>asig</emphasis> -- output sig
</para>
<para>
<emphasis>krec</emphasis> -- 'rec on' signal, 1 when recording, 0 otherwise
</para>
<para>
<emphasis>kpitch</emphasis> -- pitch control (transposition ratio); negative values play the loop back in reverse
</para>
<para>
<emphasis>ktrig</emphasis> -- trigger signal: when 0, processing is bypassed. When switched on (ktrig >= 1),
the opcode starts recording until the loop memory is full. It then plays
the looped sound until it is switched off again (ktrig = 0). Another recording
can start again with ktrig >= 1.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
<example>
<title>Example</title>
<programlisting>
asig <emphasis role="opc">in</emphasis> <emphasis role="comment">; get the signal in</emphasis>
ktrig <emphasis role="opc">line</emphasis> 0, 1, 1 <emphasis role="comment">; trigger signal</emphasis>
aout,krec <emphasis role="opc">sndloop</emphasis> asig, 1, ktrig, 4, 0.05 <emphasis role="comment">; rec starts at 1 sec, for 4 secs 0.05 crossfade</emphasis>
<emphasis role="opc">printk</emphasis> 1, krec <emphasis role="comment">; prints the recording signal</emphasis>
<emphasis role="opc">out</emphasis> aout</programlisting>
</example>
</para>
<para>
The example above shows the basic operation of sndloop. Pitch can
be controlled at the k-rate, recording is started as soon as the
trigger value is >= 1. Recording can be restarted by making the trigger 0 and
then 1 again.
</para>
</refsect1>
<refsect1>
<title>Credits</title>
<para>
<simplelist>
<member>Author: &namevictor;</member>
<member>April 2005 </member>
</simplelist>
</para>
<para>New in Version 5.00</para>
</refsect1>
</refentry>
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