<?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>downsamp</title> <link rel="stylesheet" type="text/css" href="csound.css" /> <link rel="stylesheet" type="text/css" href="syntax-highlighting.css" /> <meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /> <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="dot.html" title="dot" /> <link rel="next" href="dripwater.html" title="dripwater" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">downsamp</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="dot.html">Prev</a> </td> <th width="60%" align="center">Orchestra Opcodes and Operators</th> <td width="20%" align="right"> <a accesskey="n" href="dripwater.html">Next</a></td> </tr> </table> <hr /> </div> <div class="refentry"> <a id="downsamp"></a> <div class="titlepage"></div> <a id="IndexDownsamp" class="indexterm"></a> <div class="refnamediv"> <h2> <span class="refentrytitle">downsamp</span> </h2> <p>downsamp — Modify a signal by down-sampling. </p> </div> <div class="refsect1"> <a id="idm281472940833112"></a> <h2>Description</h2> <p> Modify a signal by down-sampling. </p> </div> <div class="refsect1"> <a id="idm281472940831784"></a> <h2>Syntax</h2> <pre class="synopsis">kres <span class="command"><strong>downsamp</strong></span> asig [, iwlen]</pre> </div> <div class="refsect1"> <a id="idm281472940829544"></a> <h2>Initialization</h2> <p> <span class="emphasis"><em>iwlen</em></span> (optional) -- window length in samples over which the audio signal is averaged to determine a downsampled value. Maximum length is <span class="emphasis"><em>ksmps</em></span>; 0 and 1 imply no window averaging. The default value is 0. </p> </div> <div class="refsect1"> <a id="idm281472940827208"></a> <h2>Performance</h2> <p> <span class="emphasis"><em>downsamp</em></span> converts an audio signal to a control signal by downsampling. It produces one kval for each audio control period. The optional window invokes a simple averaging process to suppress foldover. </p> </div> <div class="refsect1"> <a id="idm281472940825160"></a> <h2>Examples</h2> <p> Here is an example of the downsamp opcode. It uses the file <a class="ulink" href="examples/downsamp.csd" target="_top"><em class="citetitle">downsamp.csd</em></a>. </p> <div class="example"> <a id="idm281472940823384"></a> <p class="title"> <strong>Example 222. Example of the downsamp 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> <div class="refsect1"> <a id="idm281472773665656"></a> <pre class="programlisting"> <span class="nt"><CsoundSynthesizer></span> <span class="nt"><CsOptions></span> <span class="c1">; Select audio/midi flags here according to platform</span> -odac <span class="c1">;;;realtime audio out</span> <span class="c1">;-iadc ;;;uncomment -iadc if realtime audio input is needed too</span> <span class="c1">; For Non-realtime ouput leave only the line below:</span> <span class="c1">; -o downsamp.wav -W ;;; for file output any platform</span> <span class="nt"></CsOptions></span> <span class="nt"><CsInstruments></span> <span class="vg">sr</span> <span class="o">=</span> <span class="mi">44100</span> <span class="vg">ksmps</span> <span class="o">=</span> <span class="mi">32</span> <span class="vg">nchnls</span> <span class="o">=</span> <span class="mi">2</span> <span class="vg">0dbfs</span> <span class="o">=</span> <span class="mi">1</span> <span class="kd">instr</span> <span class="nf">1</span> i<span class="n">frq</span> <span class="o">=</span> <span class="nb">cpspch</span><span class="p">(</span><span class="nb">p4</span><span class="p">)</span> a<span class="n">in</span> <span class="nb">diskin2</span> <span class="s">"beats.wav"</span><span class="p">,</span> <span class="mi">1</span> a<span class="n">env</span> <span class="nb">follow</span> a<span class="n">in</span><span class="p">,</span> <span class="mf">.001</span> <span class="c1">;take the amplitude every 1/1000th of a second</span> a<span class="n">low</span> <span class="nb">tone</span> a<span class="n">env</span><span class="p">,</span> <span class="mi">25</span> <span class="c1">;lowpass-filter (25 Hz) for a clean signal</span> k<span class="n">env</span> <span class="nb">downsamp</span> a<span class="n">low</span> a<span class="n">sig</span> <span class="nb">pluck</span> k<span class="n">env</span><span class="p">,</span> i<span class="n">frq</span><span class="p">,</span> <span class="mi">15</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="mi">1</span> <span class="nb">outs</span> a<span class="n">sig</span><span class="p">,</span> a<span class="n">sig</span> <span class="kd">endin</span> <span class="nt"></CsInstruments></span> <span class="nt"><CsScore></span> <span class="nb">i</span> <span class="mi">1</span> <span class="mi">0</span> <span class="mi">2</span> <span class="mi">9</span> <span class="nb">i</span> <span class="mi">1</span> <span class="o">+</span> <span class="o">.</span> <span class="mi">7</span> <span class="nb">i</span> <span class="mi">1</span> <span class="o">+</span> <span class="o">.</span> <span class="mi">5</span> <span class="nb">e</span> <span class="nt"></CsScore></span> <span class="nt"></CsoundSynthesizer></span> </pre> </div> </div> </div> <p><br class="example-break" /> </p> </div> <div class="refsect1"> <a id="idm281472940819160"></a> <h2>See Also</h2> <p> <a class="link" href="diff.html" title="diff"><em class="citetitle">diff</em></a>, <a class="link" href="integ.html" title="integ"><em class="citetitle">integ</em></a>, <a class="link" href="interp.html" title="interp"><em class="citetitle">interp</em></a>, <a class="link" href="samphold.html" title="samphold"><em class="citetitle">samphold</em></a>, <a class="link" href="upsamp.html" title="upsamp"><em class="citetitle">upsamp</em></a> </p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="dot.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="dripwater.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">dot </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> dripwater</td> </tr> </table> </div> </body> </html>