<?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>follow2</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="follow.html" title="follow" /> <link rel="next" href="foscil.html" title="foscil" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">follow2</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="follow.html">Prev</a> </td> <th width="60%" align="center">Orchestra Opcodes and Operators</th> <td width="20%" align="right"> <a accesskey="n" href="foscil.html">Next</a></td> </tr> </table> <hr /> </div> <div class="refentry" title="follow2"> <a id="follow2"></a> <div class="titlepage"></div> <a id="IndexFollow2" class="indexterm"></a> <div class="refnamediv"> <h2> <span class="refentrytitle">follow2</span> </h2> <p>follow2 — Another controllable envelope extractor. </p> </div> <div class="refsect1" title="Description"> <a id="idp24084968"></a> <h2>Description</h2> <p> A controllable envelope extractor using the algorithm attributed to Jean-Marc Jot. </p> </div> <div class="refsect1" title="Syntax"> <a id="idp24085776"></a> <h2>Syntax</h2> <pre class="synopsis">ares <span class="command"><strong>follow2</strong></span> asig, katt, krel</pre> </div> <div class="refsect1" title="Performance"> <a id="idp24086888"></a> <h2>Performance</h2> <p> <span class="emphasis"><em>asig</em></span> -- the input signal whose envelope is followed </p> <p> <span class="emphasis"><em>katt</em></span> -- the attack rate (60dB attack time in seconds) </p> <p> <span class="emphasis"><em>krel</em></span> -- the decay rate (60dB decay time in seconds) </p> <p> The output tracks the amplitude envelope of the input signal. The rate at which the output grows to follow the signal is controlled by the <span class="emphasis"><em>katt</em></span>, and the rate at which it decreases in response to a lower amplitude, is controlled by the <span class="emphasis"><em>krel</em></span>. This gives a smoother envelope than <span class="emphasis"><em>follow</em></span>. </p> </div> <div class="refsect1" title="Examples"> <a id="idp24089992"></a> <h2>Examples</h2> <p> Here is an example of the follow2 opcode. It uses the file <a class="ulink" href="examples/follow2.csd" target="_top"><em class="citetitle">follow2.csd</em></a>, and <a class="ulink" href="examples/beats.wav" target="_top"><em class="citetitle">beats.wav</em></a>. </p> <div class="example"> <a id="idp24091408"></a> <p class="title"> <strong>Example 287. Example of the follow2 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> -odac <span class="comment">;;;realtime audio out</span> <span class="comment">;-iadc ;;;uncomment -iadc if realtime audio input is needed too</span> <span class="comment">; For Non-realtime ouput leave only the line below:</span> <span class="comment">; -o follow2.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">ksmps</span> <span class="op">=</span> 32 <span class="ohdr">nchnls</span> <span class="op">=</span> 2 <span class="ohdr">0dbfs</span> <span class="op">=</span> 1 <span class="oblock">instr</span> 1 asig <span class="opc">soundin</span> "beats.wav" <span class="opc">outs</span> asig, asig <span class="oblock">endin</span> <span class="oblock">instr</span> 2 <span class="comment">;using follow2</span> as <span class="opc">soundin</span> "beats.wav" af <span class="opc">follow2</span> as, p4, p5 ar <span class="opc">rand</span> 44100 <span class="comment">;noise</span> <span class="comment">; "beats.wav" provides amplitude for noise</span> asig <span class="opc">balance</span> ar, af <span class="opc">outs</span> asig, asig <span class="oblock">endin</span> <span class="csdtag"></CsInstruments></span> <span class="csdtag"><CsScore></span> <span class="stamnt">i</span> 1 0 2 <span class="stamnt">i</span> 2 2 2 0.001 0.01 <span class="comment">;quick attack & deacy</span> <span class="stamnt">i</span> 2 5 2 0.1 0.5 <span class="comment">;slow attack & deacy </span> <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="Credits"> <a id="idp24093688"></a> <h2>Credits</h2> <p> </p> <table border="0" summary="Simple list" class="simplelist"> <tr> <td>Author: John ffitch</td> </tr> <tr> <td>The algorithm for the <span class="emphasis"><em>follow2</em></span> is attributed to Jean-Marc Jot.</td> </tr> <tr> <td>University of Bath, Codemist Ltd.</td> </tr> <tr> <td>Bath, UK</td> </tr> <tr> <td>February 2000</td> </tr> </table> <p> </p> <p>New in Csound version 4.03</p> <p>Added notes by Rasmus Ekman on September 2002.</p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="follow.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="foscil.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">follow </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> foscil</td> </tr> </table> </div> </body> </html>