<?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>clip</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="clfilt.html" title="clfilt" /> <link rel="next" href="clockoff.html" title="clockoff" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">clip</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="clfilt.html">Prev</a> </td> <th width="60%" align="center">Orchestra Opcodes and Operators</th> <td width="20%" align="right"> <a accesskey="n" href="clockoff.html">Next</a></td> </tr> </table> <hr /> </div> <div class="refentry"> <a id="clip"></a> <div class="titlepage"></div> <a id="IndexClip" class="indexterm"></a> <div class="refnamediv"> <h2> <span class="refentrytitle">clip</span> </h2> <p>clip — Clips a signal to a predefined limit. </p> </div> <div class="refsect1"> <a id="idm281472946484536"></a> <h2>Description</h2> <p> Clips an a-rate signal to a predefined limit, in a <span class="quote">“<span class="quote">soft</span>”</span> manner, using one of three methods. </p> </div> <div class="refsect1"> <a id="idm281472946482904"></a> <h2>Syntax</h2> <pre class="synopsis">ares <span class="command"><strong>clip</strong></span> asig, imeth, ilimit [, iarg]</pre> </div> <div class="refsect1"> <a id="idm281472946480680"></a> <h2>Initialization</h2> <p> <span class="emphasis"><em>imeth</em></span> -- selects the clipping method. The default is 0. The methods are: </p> <div class="itemizedlist"> <ul class="itemizedlist" style="list-style-type: disc; "> <li class="listitem"> <p>0 = Bram de Jong method (default)</p> </li> <li class="listitem"> <p>1 = sine clipping</p> </li> <li class="listitem"> <p>2 = tanh clipping</p> </li> </ul> </div> <p> </p> <p> <span class="emphasis"><em>ilimit</em></span> -- limiting value </p> <p> <span class="emphasis"><em>iarg</em></span> (optional, default=0.5) -- when <span class="emphasis"><em>imeth</em></span> = 0, indicates the point at which clipping starts, in the range 0 - 1. Not used when <span class="emphasis"><em>imeth</em></span> = 1 or <span class="emphasis"><em>imeth</em></span> = 2. Default is 0.5. </p> </div> <div class="refsect1"> <a id="idm281472946400648"></a> <h2>Performance</h2> <p> <span class="emphasis"><em>asig</em></span> -- a-rate input signal </p> <p> The Bram de Jong method (<span class="emphasis"><em>imeth</em></span> = 0) applies the algorithm (denoting <span class="emphasis"><em>ilimit</em></span> as <span class="emphasis"><em>limit</em></span> and <span class="emphasis"><em>iarg</em></span> as <span class="emphasis"><em>a</em></span>): </p> <p> </p> <div class="informalexample"> <pre class="programlisting"> |<span class="emphasis"><em>x</em></span>| >= 0 and |<span class="emphasis"><em>x</em></span>| <= (<span class="emphasis"><em>limit*a</em></span>): f(<span class="emphasis"><em>x</em></span>) = f(<span class="emphasis"><em>x</em></span>) |<span class="emphasis"><em>x</em></span>| > (<span class="emphasis"><em>limit*a</em></span>) and |<span class="emphasis"><em>x</em></span>| <= <span class="emphasis"><em>limit</em></span>: f(<span class="emphasis"><em>x</em></span>) = sign(<span class="emphasis"><em>x</em></span>) * (<span class="emphasis"><em>limit*a</em></span>+(<span class="emphasis"><em>x-limit*a</em></span>)/(1+((<span class="emphasis"><em>x-limit*a</em></span>)/(<span class="emphasis"><em>limit</em></span>*(1-<span class="emphasis"><em>a</em></span>)))<sup>2</sup>)) |<span class="emphasis"><em>x</em></span>| > <span class="emphasis"><em>limit</em></span>: f(<span class="emphasis"><em>x</em></span>) = sign(<span class="emphasis"><em>x</em></span>) * (<span class="emphasis"><em>limit</em></span>*(<span class="emphasis"><em>1+a</em></span>))/2</pre> </div> <p> </p> <p> The second method (<span class="emphasis"><em>imeth</em></span> = 1) is the sine clip: </p> <p> </p> <div class="informalexample"> <pre class="programlisting"> |<span class="emphasis"><em>x</em></span>| < <span class="emphasis"><em>limit</em></span>: f(<span class="emphasis"><em>x</em></span>) = <span class="emphasis"><em>limit</em></span> * sin(π*<span class="emphasis"><em>x</em></span>/(2*<span class="emphasis"><em>limit</em></span>)), |<span class="emphasis"><em>x</em></span>| >= <span class="emphasis"><em>limit</em></span>: f(<span class="emphasis"><em>x</em></span>) = <span class="emphasis"><em>limit</em></span> * sign(<span class="emphasis"><em>x</em></span>)</pre> </div> <p> </p> <p> The third method (<span class="emphasis"><em>imeth = 2</em></span>) is the tanh clip: </p> <p> </p> <div class="informalexample"> <pre class="programlisting"> |<span class="emphasis"><em>x</em></span>| < <span class="emphasis"><em>limit</em></span>: f(<span class="emphasis"><em>x</em></span>) = <span class="emphasis"><em>limit</em></span> * tanh(<span class="emphasis"><em>x/limit</em></span>)/tanh(1), |<span class="emphasis"><em>x</em></span>| >= <span class="emphasis"><em>limit</em></span>: f(<span class="emphasis"><em>x</em></span>) = <span class="emphasis"><em>limit</em></span> * sign(<span class="emphasis"><em>x</em></span>)</pre> </div> <p> </p> <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> <table border="0" summary="Note: Note"> <tr> <td rowspan="2" align="center" valign="top" width="25"> <img alt="[Note]" src="images/note.png" /> </td> <th align="left">Note</th> </tr> <tr> <td align="left" valign="top"> <p> Method 1 appears to be non-functional at release of Csound version 4.07. </p> </td> </tr> </table> </div> </div> <div class="refsect1"> <a id="idm281472946368744"></a> <h2>Examples</h2> <p> Here is an example of the clip opcode. It uses the file <a class="ulink" href="examples/clip.csd" target="_top"><em class="citetitle">clip.csd</em></a>. </p> <div class="example"> <a id="idm281472946366888"></a> <p class="title"> <strong>Example 132. Example of the clip 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="idm281472779696824"></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">;;;RT audio out</span> <span class="c1">;-iadc ;;;uncomment -iadc if RT audio input is needed too</span> <span class="c1">; For Non-realtime ouput leave only the line below:</span> <span class="c1">; -o clip.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> <span class="c1">; white noise</span> a<span class="n">rnd</span> <span class="nb">rand</span> <span class="mi">1</span> <span class="c1">; full amlitude</span> <span class="c1">; Clip the noisy waveform's amplitude to 0.5</span> a<span class="n">1</span> <span class="nb">clip</span> a<span class="n">rnd</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mf">0.5</span> <span class="nb">outs</span> a<span class="n">1</span><span class="p">,</span> a<span class="n">1</span> <span class="kd">endin</span> <span class="kd">instr</span> <span class="nf">2</span> <span class="c1">; white noise</span> a<span class="n">rnd</span> <span class="nb">rand</span> <span class="mi">1</span> <span class="c1">; full amlitude</span> <span class="c1">; Clip the noisy waveform's amplitude to 0.1</span> a<span class="n">1</span> <span class="nb">clip</span> a<span class="n">rnd</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mf">0.1</span> <span class="nb">outs</span> a<span class="n">1</span><span class="p">,</span> a<span class="n">1</span> <span class="kd">endin</span> <span class="nt"></CsInstruments></span> <span class="nt"><CsScore></span> <span class="c1">; Play Instrument #1 for one second.</span> <span class="nb">i</span> <span class="mi">1</span> <span class="mi">0</span> <span class="mi">1</span> <span class="c1">; Play Instrument #2 for one second.</span> <span class="nb">i</span> <span class="mi">2</span> <span class="mi">1</span> <span class="mi">1</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="idm281472946362696"></a> <h2>Credits</h2> <p> </p> <table border="0" summary="Simple list" class="simplelist"> <tr> <td>Author: John ffitch</td> </tr> <tr> <td>University of Bath, Codemist Ltd.</td> </tr> <tr> <td>Bath, UK</td> </tr> <tr> <td>August, 2000</td> </tr> </table> <p> </p> <p>New in Csound version 4.07</p> <p>September 2009: Thanks to a note from Paolo Dell'Osso, corrected the formula.</p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="clfilt.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="clockoff.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">clfilt </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> clockoff</td> </tr> </table> </div> </body> </html>