<?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>0dbfs</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="opnot.html" title="!" /> <link rel="next" href="A4.html" title="A4" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">0dbfs</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="opnot.html">Prev</a> </td> <th width="60%" align="center">Orchestra Opcodes and Operators</th> <td width="20%" align="right"> <a accesskey="n" href="A4.html">Next</a></td> </tr> </table> <hr /> </div> <div class="refentry"> <a id="Zerodbfs"></a> <div class="titlepage"></div> <a id="Index0dbfs" class="indexterm"></a> <div class="refnamediv"> <h2> <span class="refentrytitle">0dbfs</span> </h2> <p>0dbfs — Sets the value of 0 decibels using full scale amplitude. </p> </div> <div class="refsect1"> <a id="idm281472952639128"></a> <h2>Description</h2> <p> Sets the value of 0 decibels using full scale amplitude. </p> </div> <div class="refsect1"> <a id="idm281472952566312"></a> <h2>Syntax</h2> <pre class="synopsis"><span class="command"><strong>0dbfs</strong></span> = iarg</pre> <pre class="synopsis"><span class="command"><strong>0dbfs</strong></span> </pre> </div> <div class="refsect1"> <a id="idm281472952563112"></a> <h2>Initialization</h2> <p> <span class="emphasis"><em>iarg</em></span> -- the value of 0 decibels using full scale amplitude. </p> </div> <div class="refsect1"> <a id="idm281472952561336"></a> <h2>Performance</h2> <p> The default is 32767, so all existing orcs <span class="emphasis"><em>should</em></span> work. </p> <p> Amplitude values in Csound are always relative to a "<a class="link" href="Zerodbfs.html" title="0dbfs"><em class="citetitle">0dbfs</em></a>" value representing the peak available amplitude before clipping. In the original Csound, this value was always 32767, corresponding to the bipolar range of a 16bit soundfile or 16bit AD/DA codec. This remains the <span class="emphasis"><em>default</em></span> peak amplitude for Csound, for backward compatibility. The <a class="link" href="Zerodbfs.html" title="0dbfs"><em class="citetitle">0dbfs</em></a> value enables Csound to produce appropriately scaled values to whatever output format is being used, whether 16bit integer, 24bit integer, 32bit floats, or even 32bit integers. </p> <p> OdBFS can be defined in the header, to set the amplitude reference Csound will use, but it can also be used as a varible inside instruments like this: </p> <div class="informalexample"> <pre class="programlisting">ipeak <span class="op">=</span> <span class="ohdr">0dbfs</span></pre> </div> <p> </p> <div class="informalexample"> <pre class="programlisting"> asig <span class="opc">oscil</span> <span class="ohdr">0dbfs</span>, freq, 1 <span class="opc">out</span> asig * 0.3 * <span class="ohdr">0dbfs</span></pre> </div> <p> </p> <p> The purpose of the <span class="emphasis"><em>0dbfs</em></span> opcode is for people to start to code 0dbfs-relatively (and use the <a class="link" href="ampdbfs.html" title="ampdbfs"><em class="citetitle">ampdbfs()</em></a> opcodes a lot more!), rather than use explicit sample values. Using 0dbfs=1 is in accordance to industry practice, as ranges from -1 to 1 are used in most commercial plugin formats and in most other synthesis systems like Pure Data. </p> <p> Floats written to a file, when <span class="emphasis"><em>0dbfs = 1</em></span>, will in effect go through no range translation at all. So the numbers in the file are exactly what the orc says they are. </p> <p>For more details on amplitude values in Csound, see the section <a class="link" href="UsingDesign.html#AmplitudeCsound" title="Amplitude values in Csound"><em class="citetitle">Amplitude values in Csound</em></a></p> </div> <div class="refsect1"> <a id="idm281472952543464"></a> <h2>Example</h2> <p> Here is an example of the 0dbfs opcode. It uses the file <a class="ulink" href="examples/0dbfs.csd" target="_top"><em class="citetitle">0dbfs.csd</em></a>. </p> <div class="example"> <a id="idm281472952541608"></a> <p class="title"> <strong>Example 37. Example of the 0dbfs 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="idm281472788273320"></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> <span class="c1">; Audio out Audio in No messages</span> -odac -iadc -d <span class="c1">;;;RT audio I/O</span> <span class="c1">; For Non-realtime ouput leave only the line below:</span> <span class="c1">; -o 0dbfs.wav -W ;;; for file output any platform</span> <span class="nt"></CsOptions></span> <span class="nt"><CsInstruments></span> <span class="c1">; Initialize the global variables.</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">10</span> <span class="vg">nchnls</span> <span class="o">=</span> <span class="mi">2</span> <span class="c1">; Set the 0dbfs to 1.</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">; from linear amplitude (0-1 range)</span> <span class="nb">print</span> <span class="nb">p4</span> a<span class="n">1</span> <span class="nb">oscil</span> <span class="nb">p4</span><span class="p">,</span> <span class="mi">440</span><span class="p">,</span> <span class="mi">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="kd">instr</span> <span class="nf">2</span> <span class="c1">; from linear amplitude (0-32767 range)</span> i<span class="n">amp</span> <span class="o">=</span> <span class="nb">p4</span> <span class="o">/</span> <span class="mi">32767</span> <span class="nb">print</span> i<span class="n">amp</span> a<span class="n">1</span> <span class="nb">oscil</span> i<span class="n">amp</span><span class="p">,</span> <span class="mi">440</span><span class="p">,</span> <span class="mi">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="kd">instr</span> <span class="nf">3</span> <span class="c1">; from dB FS</span> i<span class="n">amp</span> <span class="o">=</span> <span class="nb">ampdbfs</span><span class="p">(</span><span class="nb">p4</span><span class="p">)</span> <span class="nb">print</span> i<span class="n">amp</span> a<span class="n">1</span> <span class="nb">oscil</span> i<span class="n">amp</span><span class="p">,</span> <span class="mi">440</span><span class="p">,</span> <span class="mi">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">; Table #1, a sine wave.</span> <span class="nb">f</span> <span class="mi">1</span> <span class="mi">0</span> <span class="mi">16384</span> <span class="mi">10</span> <span class="mi">1</span> <span class="nb">i</span> <span class="mi">1</span> <span class="mi">0</span> <span class="mi">1</span> <span class="mi">1</span> <span class="nb">i</span> <span class="mi">1</span> <span class="o">+</span> <span class="mi">1</span> <span class="mf">0.5</span> <span class="nb">i</span> <span class="mi">1</span> <span class="o">+</span> <span class="mi">1</span> <span class="mf">0.1</span> <span class="nb">s</span> <span class="nb">i</span> <span class="mi">2</span> <span class="mi">0</span> <span class="mi">1</span> <span class="mi">32767</span> <span class="nb">i</span> <span class="mi">2</span> <span class="o">+</span> <span class="mi">1</span> <span class="p">[</span><span class="mi">32767</span><span class="o">/</span><span class="mi">2</span><span class="p">]</span> <span class="nb">i</span> <span class="mi">2</span> <span class="o">+</span> <span class="mi">1</span> <span class="p">[</span><span class="mf">3276.7</span><span class="p">]</span> <span class="nb">s</span> <span class="nb">i</span> <span class="mi">3</span> <span class="mi">0</span> <span class="mi">1</span> <span class="mi">0</span> <span class="nb">i</span> <span class="mi">3</span> <span class="o">+</span> <span class="mi">1</span> <span class="o">-</span><span class="mi">6</span> <span class="nb">i</span> <span class="mi">3</span> <span class="o">+</span> <span class="mi">1</span> <span class="o">-</span><span class="mi">20</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="idm281472952537384"></a> <h2>See also</h2> <p> <a class="link" href="ampdbfs.html" title="ampdbfs"> <em class="citetitle">ampdbfs()</em> </a> </p> </div> <div class="refsect1"> <a id="idm281472952535560"></a> <h2>Credits</h2> <p> </p> <table border="0" summary="Simple list" class="simplelist"> <tr> <td>Author: Richard Dobson</td> </tr> <tr> <td>May 2002</td> </tr> </table> <p> </p> <p>New in version 4.10</p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="opnot.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="A4.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">! </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> A4</td> </tr> </table> </div> </body> </html>