<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>dconv</title>
<link rel="stylesheet" type="text/css" href="csound.css" />
<meta name="generator" content="DocBook XSL Stylesheets V1.76.1" />
<link rel="home" href="index.html" title="The Canonical Csound Reference Manual" />
<link rel="up" href="OpcodesTop.html" title="Orchestra Opcodes and Operators" />
<link rel="prev" href="dcblock2.html" title="dcblock2" />
<link rel="next" href="delay.html" title="delay" />
</head>
<body>
<div class="navheader">
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">dconv</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="dcblock2.html">Prev</a> </td>
<th width="60%" align="center">Orchestra Opcodes and Operators</th>
<td width="20%" align="right"> <a accesskey="n" href="delay.html">Next</a></td>
</tr>
</table>
<hr />
</div>
<div class="refentry" title="dconv">
<a id="dconv"></a>
<div class="titlepage"></div>
<a id="IndexDconv" class="indexterm"></a>
<div class="refnamediv">
<h2>
<span class="refentrytitle">dconv</span>
</h2>
<p>dconv —
A direct convolution opcode.
</p>
</div>
<div class="refsect1" title="Description">
<a id="idp17732760"></a>
<h2>Description</h2>
<p>
A direct convolution opcode.
</p>
</div>
<div class="refsect1" title="Syntax">
<a id="idp17733400"></a>
<h2>Syntax</h2>
<pre class="synopsis">ares <span class="command"><strong>dconv</strong></span> asig, isize, ifn</pre>
</div>
<div class="refsect1" title="Initialization">
<a id="idp17743856"></a>
<h2>Initialization</h2>
<p>
<span class="emphasis"><em>isize</em></span> -- the size of the convolution buffer to use. If the buffer size is smaller than the size of <span class="emphasis"><em>ifn</em></span>, then only the first <span class="emphasis"><em>isize</em></span> values will be used from the table.
</p>
<p>
<span class="emphasis"><em>ifn</em></span> -- table number of a stored function containing the impulse response for convolution.
</p>
</div>
<div class="refsect1" title="Performance">
<a id="idp17745696"></a>
<h2>Performance</h2>
<p>
Rather than the analysis/resynthesis method of the <span class="emphasis"><em>convolve</em></span> opcode, <span class="emphasis"><em>dconv</em></span> uses direct convolution to create the result. For small tables it can do this quite efficiently, however larger table require much more time to run. <span class="emphasis"><em>dconv</em></span> does (<span class="emphasis"><em>isize</em></span> * <span class="emphasis"><em>ksmps</em></span>) multiplies on every k-cycle. Therefore, reverb and delay effects are best done with other opcodes (unless the times are short).
</p>
<p>
<span class="emphasis"><em>dconv</em></span> was designed to be used with time varying tables to facilitate new realtime filtering capabilities.
</p>
</div>
<div class="refsect1" title="Examples">
<a id="idp17748240"></a>
<h2>Examples</h2>
<p>
Here is an example of the dconv opcode. It uses the file <a class="ulink" href="examples/dconv.csd" target="_top"><em class="citetitle">dconv.csd</em></a>.
</p>
<div class="example">
<a id="idp17749208"></a>
<p class="title">
<strong>Example 158. Example of the dconv opcode.</strong>
</p>
<div class="example-contents">
<p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
<pre class="programlisting">
<span class="csdtag"><CsoundSynthesizer></span>
<span class="csdtag"><CsOptions></span>
<span class="comment">; Select audio/midi flags here according to platform</span>
<span class="comment">; Audio out Audio in No messages</span>
-odac -iadc -d <span class="comment">;;;RT audio I/O</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o dconv.wav -W ;;; for file output any platform</span>
<span class="csdtag"></CsOptions></span>
<span class="csdtag"><CsInstruments></span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">kr</span> <span class="op">=</span> 4410
<span class="ohdr">ksmps</span> <span class="op">=</span> 10
<span class="ohdr">nchnls</span> <span class="op">=</span> 1
<span class="omacro">#define</span> RANDI(A) #kout <span class="opc">randi</span> 1, kfq, $A<span class="op">*</span>.001<span class="op">+</span>iseed, 1
<span class="opc">tablew</span> kout, $A, itable#
<span class="oblock">instr</span> 1
itable <span class="opc">init</span> 1
iseed <span class="opc">init</span> .6
isize <span class="opc">init</span> <span class="opc">ftlen</span>(itable)
kfq <span class="opc">line</span> 1, p3, 10
$RANDI(0)
$RANDI(1)
$RANDI(2)
$RANDI(3)
$RANDI(4)
$RANDI(5)
$RANDI(6)
$RANDI(7)
$RANDI(8)
$RANDI(9)
$RANDI(10)
$RANDI(11)
$RANDI(12)
$RANDI(13)
$RANDI(14)
$RANDI(15)
asig <span class="opc">rand</span> 10000, .5, 1
asig <span class="opc">butlp</span> asig, 5000
asig <span class="opc">dconv</span> asig, isize, itable
<span class="opc">out</span> asig <span class="op">*</span>.5
<span class="oblock">endin</span>
<span class="csdtag"></CsInstruments></span>
<span class="csdtag"><CsScore></span>
<span class="stamnt">f</span>1 0 16 10 1
<span class="stamnt">i</span>1 0 10
<span class="stamnt">e</span>
<span class="csdtag"></CsScore></span>
<span class="csdtag"></CsoundSynthesizer></span>
</pre>
</div>
</div>
<p><br class="example-break" />
</p>
</div>
<div class="refsect1" title="See also">
<a id="idp17782648"></a>
<h2>See also</h2>
<p>
<a class="link" href="pconvolve.html" title="pconvolve"><em class="citetitle">pconvolve</em></a>,
<a class="link" href="convolve.html" title="convolve"><em class="citetitle">convolve</em></a>,
<a class="link" href="ftconv.html" title="ftconv"><em class="citetitle">ftconv</em></a>
</p>
</div>
<div class="refsect1" title="Credits">
<a id="idp17784624"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: William <span class="quote">“<span class="quote">Pete</span>”</span> Moss</td>
</tr>
<tr>
<td>2001</td>
</tr>
</table>
<p>
</p>
<p>New in version 4.12</p>
</div>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="dcblock2.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="OpcodesTop.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="delay.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">dcblock2 </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> delay</td>
</tr>
</table>
</div>
</body>
</html>
distrib
>
Mageia
>
5
>
x86_64
>
media
>
core-release
>
by-pkgid
>
b707d9a4ee443103660a75ccb6e51334
>
files
>
521
