1501 lines
49 KiB
HTML
1501 lines
49 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Created by GNU Texinfo 6.8, https://www.gnu.org/software/texinfo/ -->
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<head>
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<meta charset="utf-8">
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<title>
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FFmpeg Utilities Documentation
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</title>
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<meta name="viewport" content="width=device-width,initial-scale=1.0">
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<link rel="stylesheet" type="text/css" href="bootstrap.min.css">
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<link rel="stylesheet" type="text/css" href="style.min.css">
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</head>
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<body>
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<div class="container">
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<h1>
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FFmpeg Utilities Documentation
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</h1>
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<div align="center">
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</div>
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<a name="SEC_Top"></a>
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<div class="Contents_element" id="SEC_Contents">
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<h2 class="contents-heading">Table of Contents</h2>
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<div class="contents">
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<ul class="no-bullet">
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<li><a id="toc-Description" href="#Description">1 Description</a></li>
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<li><a id="toc-Syntax" href="#Syntax">2 Syntax</a>
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<ul class="no-bullet">
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<li><a id="toc-Quoting-and-escaping" href="#Quoting-and-escaping">2.1 Quoting and escaping</a>
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<ul class="no-bullet">
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<li><a id="toc-Examples" href="#Examples">2.1.1 Examples</a></li>
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</ul></li>
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<li><a id="toc-Date" href="#Date">2.2 Date</a></li>
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<li><a id="toc-Time-duration" href="#Time-duration">2.3 Time duration</a>
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<ul class="no-bullet">
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<li><a id="toc-Examples-1" href="#Examples-1">2.3.1 Examples</a></li>
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</ul></li>
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<li><a id="toc-Video-size" href="#Video-size">2.4 Video size</a></li>
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<li><a id="toc-Video-rate" href="#Video-rate">2.5 Video rate</a></li>
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<li><a id="toc-Ratio" href="#Ratio">2.6 Ratio</a></li>
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<li><a id="toc-Color" href="#Color">2.7 Color</a></li>
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<li><a id="toc-Channel-Layout" href="#Channel-Layout">2.8 Channel Layout</a></li>
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</ul></li>
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<li><a id="toc-Expression-Evaluation" href="#Expression-Evaluation">3 Expression Evaluation</a></li>
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<li><a id="toc-See-Also" href="#See-Also">4 See Also</a></li>
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<li><a id="toc-Authors" href="#Authors">5 Authors</a></li>
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</ul>
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</div>
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</div>
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<a name="Description"></a>
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<h2 class="chapter">1 Description<span class="pull-right"><a class="anchor hidden-xs" href="#Description" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Description" aria-hidden="true">TOC</a></span></h2>
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<p>This document describes some generic features and utilities provided
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by the libavutil library.
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</p>
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<a name="Syntax"></a>
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<h2 class="chapter">2 Syntax<span class="pull-right"><a class="anchor hidden-xs" href="#Syntax" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Syntax" aria-hidden="true">TOC</a></span></h2>
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<p>This section documents the syntax and formats employed by the FFmpeg
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libraries and tools.
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</p>
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<span id="quoting_005fand_005fescaping"></span><a name="Quoting-and-escaping"></a>
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<h3 class="section">2.1 Quoting and escaping<span class="pull-right"><a class="anchor hidden-xs" href="#Quoting-and-escaping" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Quoting-and-escaping" aria-hidden="true">TOC</a></span></h3>
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<p>FFmpeg adopts the following quoting and escaping mechanism, unless
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explicitly specified. The following rules are applied:
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</p>
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<ul>
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<li> ‘<samp>'</samp>’ and ‘<samp>\</samp>’ are special characters (respectively used for
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quoting and escaping). In addition to them, there might be other
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special characters depending on the specific syntax where the escaping
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and quoting are employed.
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</li><li> A special character is escaped by prefixing it with a ‘<samp>\</samp>’.
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</li><li> All characters enclosed between ‘<samp>''</samp>’ are included literally in the
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parsed string. The quote character ‘<samp>'</samp>’ itself cannot be quoted,
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so you may need to close the quote and escape it.
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</li><li> Leading and trailing whitespaces, unless escaped or quoted, are
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removed from the parsed string.
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</li></ul>
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<p>Note that you may need to add a second level of escaping when using
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the command line or a script, which depends on the syntax of the
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adopted shell language.
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</p>
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<p>The function <code>av_get_token</code> defined in
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<samp>libavutil/avstring.h</samp> can be used to parse a token quoted or
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escaped according to the rules defined above.
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</p>
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<p>The tool <samp>tools/ffescape</samp> in the FFmpeg source tree can be used
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to automatically quote or escape a string in a script.
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</p>
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<a name="Examples"></a>
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<h4 class="subsection">2.1.1 Examples<span class="pull-right"><a class="anchor hidden-xs" href="#Examples" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Examples" aria-hidden="true">TOC</a></span></h4>
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<ul>
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<li> Escape the string <code>Crime d'Amour</code> containing the <code>'</code> special
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character:
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<div class="example">
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<pre class="example">Crime d\'Amour
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</pre></div>
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</li><li> The string above contains a quote, so the <code>'</code> needs to be escaped
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when quoting it:
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<div class="example">
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<pre class="example">'Crime d'\''Amour'
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</pre></div>
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</li><li> Include leading or trailing whitespaces using quoting:
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<div class="example">
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<pre class="example">' this string starts and ends with whitespaces '
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</pre></div>
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</li><li> Escaping and quoting can be mixed together:
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<div class="example">
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<pre class="example">' The string '\'string\'' is a string '
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</pre></div>
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</li><li> To include a literal ‘<samp>\</samp>’ you can use either escaping or quoting:
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<div class="example">
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<pre class="example">'c:\foo' can be written as c:\\foo
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</pre></div>
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</li></ul>
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<span id="date-syntax"></span><a name="Date"></a>
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<h3 class="section">2.2 Date<span class="pull-right"><a class="anchor hidden-xs" href="#Date" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Date" aria-hidden="true">TOC</a></span></h3>
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<p>The accepted syntax is:
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</p><div class="example">
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<pre class="example">[(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...]]])|(HHMMSS[.m...]]]))[Z]
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now
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</pre></div>
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<p>If the value is "now" it takes the current time.
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</p>
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<p>Time is local time unless Z is appended, in which case it is
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interpreted as UTC.
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If the year-month-day part is not specified it takes the current
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year-month-day.
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</p>
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<span id="time-duration-syntax"></span><a name="Time-duration"></a>
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<h3 class="section">2.3 Time duration<span class="pull-right"><a class="anchor hidden-xs" href="#Time-duration" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Time-duration" aria-hidden="true">TOC</a></span></h3>
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<p>There are two accepted syntaxes for expressing time duration.
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</p>
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<div class="example">
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<pre class="example">[-][<var>HH</var>:]<var>MM</var>:<var>SS</var>[.<var>m</var>...]
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</pre></div>
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<p><var>HH</var> expresses the number of hours, <var>MM</var> the number of minutes
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for a maximum of 2 digits, and <var>SS</var> the number of seconds for a
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maximum of 2 digits. The <var>m</var> at the end expresses decimal value for
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<var>SS</var>.
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</p>
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<p><em>or</em>
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</p>
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<div class="example">
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<pre class="example">[-]<var>S</var>+[.<var>m</var>...][s|ms|us]
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</pre></div>
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<p><var>S</var> expresses the number of seconds, with the optional decimal part
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<var>m</var>. The optional literal suffixes ‘<samp>s</samp>’, ‘<samp>ms</samp>’ or ‘<samp>us</samp>’
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indicate to interpret the value as seconds, milliseconds or microseconds,
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respectively.
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</p>
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<p>In both expressions, the optional ‘<samp>-</samp>’ indicates negative duration.
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</p>
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<a name="Examples-1"></a>
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<h4 class="subsection">2.3.1 Examples<span class="pull-right"><a class="anchor hidden-xs" href="#Examples-1" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Examples-1" aria-hidden="true">TOC</a></span></h4>
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<p>The following examples are all valid time duration:
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</p>
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<dl compact="compact">
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<dt><span>‘<samp>55</samp>’</span></dt>
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<dd><p>55 seconds
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</p>
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</dd>
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<dt><span>‘<samp>0.2</samp>’</span></dt>
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<dd><p>0.2 seconds
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</p>
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</dd>
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<dt><span>‘<samp>200ms</samp>’</span></dt>
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<dd><p>200 milliseconds, that’s 0.2s
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</p>
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</dd>
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<dt><span>‘<samp>200000us</samp>’</span></dt>
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<dd><p>200000 microseconds, that’s 0.2s
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</p>
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</dd>
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<dt><span>‘<samp>12:03:45</samp>’</span></dt>
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<dd><p>12 hours, 03 minutes and 45 seconds
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</p>
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</dd>
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<dt><span>‘<samp>23.189</samp>’</span></dt>
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<dd><p>23.189 seconds
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</p></dd>
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</dl>
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<span id="video-size-syntax"></span><a name="Video-size"></a>
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<h3 class="section">2.4 Video size<span class="pull-right"><a class="anchor hidden-xs" href="#Video-size" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Video-size" aria-hidden="true">TOC</a></span></h3>
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<p>Specify the size of the sourced video, it may be a string of the form
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<var>width</var>x<var>height</var>, or the name of a size abbreviation.
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</p>
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<p>The following abbreviations are recognized:
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</p><dl compact="compact">
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<dt><span>‘<samp>ntsc</samp>’</span></dt>
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<dd><p>720x480
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</p></dd>
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<dt><span>‘<samp>pal</samp>’</span></dt>
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<dd><p>720x576
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</p></dd>
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<dt><span>‘<samp>qntsc</samp>’</span></dt>
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<dd><p>352x240
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</p></dd>
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<dt><span>‘<samp>qpal</samp>’</span></dt>
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<dd><p>352x288
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</p></dd>
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<dt><span>‘<samp>sntsc</samp>’</span></dt>
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<dd><p>640x480
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</p></dd>
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<dt><span>‘<samp>spal</samp>’</span></dt>
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<dd><p>768x576
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</p></dd>
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<dt><span>‘<samp>film</samp>’</span></dt>
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<dd><p>352x240
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</p></dd>
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<dt><span>‘<samp>ntsc-film</samp>’</span></dt>
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<dd><p>352x240
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</p></dd>
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<dt><span>‘<samp>sqcif</samp>’</span></dt>
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<dd><p>128x96
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</p></dd>
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<dt><span>‘<samp>qcif</samp>’</span></dt>
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<dd><p>176x144
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</p></dd>
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<dt><span>‘<samp>cif</samp>’</span></dt>
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<dd><p>352x288
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</p></dd>
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<dt><span>‘<samp>4cif</samp>’</span></dt>
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<dd><p>704x576
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</p></dd>
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<dt><span>‘<samp>16cif</samp>’</span></dt>
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<dd><p>1408x1152
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</p></dd>
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<dt><span>‘<samp>qqvga</samp>’</span></dt>
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<dd><p>160x120
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</p></dd>
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<dt><span>‘<samp>qvga</samp>’</span></dt>
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<dd><p>320x240
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</p></dd>
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<dt><span>‘<samp>vga</samp>’</span></dt>
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<dd><p>640x480
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</p></dd>
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<dt><span>‘<samp>svga</samp>’</span></dt>
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<dd><p>800x600
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</p></dd>
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<dt><span>‘<samp>xga</samp>’</span></dt>
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<dd><p>1024x768
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</p></dd>
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<dt><span>‘<samp>uxga</samp>’</span></dt>
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<dd><p>1600x1200
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</p></dd>
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<dt><span>‘<samp>qxga</samp>’</span></dt>
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<dd><p>2048x1536
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</p></dd>
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<dt><span>‘<samp>sxga</samp>’</span></dt>
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<dd><p>1280x1024
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</p></dd>
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<dt><span>‘<samp>qsxga</samp>’</span></dt>
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<dd><p>2560x2048
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</p></dd>
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||
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<dt><span>‘<samp>hsxga</samp>’</span></dt>
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||
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<dd><p>5120x4096
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</p></dd>
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||
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<dt><span>‘<samp>wvga</samp>’</span></dt>
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<dd><p>852x480
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</p></dd>
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<dt><span>‘<samp>wxga</samp>’</span></dt>
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<dd><p>1366x768
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</p></dd>
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<dt><span>‘<samp>wsxga</samp>’</span></dt>
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<dd><p>1600x1024
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</p></dd>
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<dt><span>‘<samp>wuxga</samp>’</span></dt>
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<dd><p>1920x1200
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</p></dd>
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<dt><span>‘<samp>woxga</samp>’</span></dt>
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<dd><p>2560x1600
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</p></dd>
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<dt><span>‘<samp>wqsxga</samp>’</span></dt>
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<dd><p>3200x2048
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</p></dd>
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<dt><span>‘<samp>wquxga</samp>’</span></dt>
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<dd><p>3840x2400
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</p></dd>
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<dt><span>‘<samp>whsxga</samp>’</span></dt>
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<dd><p>6400x4096
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|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>whuxga</samp>’</span></dt>
|
||
|
|
<dd><p>7680x4800
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>cga</samp>’</span></dt>
|
||
|
|
<dd><p>320x200
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>ega</samp>’</span></dt>
|
||
|
|
<dd><p>640x350
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>hd480</samp>’</span></dt>
|
||
|
|
<dd><p>852x480
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>hd720</samp>’</span></dt>
|
||
|
|
<dd><p>1280x720
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>hd1080</samp>’</span></dt>
|
||
|
|
<dd><p>1920x1080
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>2k</samp>’</span></dt>
|
||
|
|
<dd><p>2048x1080
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>2kflat</samp>’</span></dt>
|
||
|
|
<dd><p>1998x1080
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>2kscope</samp>’</span></dt>
|
||
|
|
<dd><p>2048x858
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>4k</samp>’</span></dt>
|
||
|
|
<dd><p>4096x2160
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>4kflat</samp>’</span></dt>
|
||
|
|
<dd><p>3996x2160
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>4kscope</samp>’</span></dt>
|
||
|
|
<dd><p>4096x1716
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>nhd</samp>’</span></dt>
|
||
|
|
<dd><p>640x360
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>hqvga</samp>’</span></dt>
|
||
|
|
<dd><p>240x160
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>wqvga</samp>’</span></dt>
|
||
|
|
<dd><p>400x240
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>fwqvga</samp>’</span></dt>
|
||
|
|
<dd><p>432x240
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>hvga</samp>’</span></dt>
|
||
|
|
<dd><p>480x320
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>qhd</samp>’</span></dt>
|
||
|
|
<dd><p>960x540
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>2kdci</samp>’</span></dt>
|
||
|
|
<dd><p>2048x1080
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>4kdci</samp>’</span></dt>
|
||
|
|
<dd><p>4096x2160
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>uhd2160</samp>’</span></dt>
|
||
|
|
<dd><p>3840x2160
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>uhd4320</samp>’</span></dt>
|
||
|
|
<dd><p>7680x4320
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<span id="video-rate-syntax"></span><a name="Video-rate"></a>
|
||
|
|
<h3 class="section">2.5 Video rate<span class="pull-right"><a class="anchor hidden-xs" href="#Video-rate" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Video-rate" aria-hidden="true">TOC</a></span></h3>
|
||
|
|
|
||
|
|
<p>Specify the frame rate of a video, expressed as the number of frames
|
||
|
|
generated per second. It has to be a string in the format
|
||
|
|
<var>frame_rate_num</var>/<var>frame_rate_den</var>, an integer number, a float
|
||
|
|
number or a valid video frame rate abbreviation.
|
||
|
|
</p>
|
||
|
|
<p>The following abbreviations are recognized:
|
||
|
|
</p><dl compact="compact">
|
||
|
|
<dt><span>‘<samp>ntsc</samp>’</span></dt>
|
||
|
|
<dd><p>30000/1001
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>pal</samp>’</span></dt>
|
||
|
|
<dd><p>25/1
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>qntsc</samp>’</span></dt>
|
||
|
|
<dd><p>30000/1001
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>qpal</samp>’</span></dt>
|
||
|
|
<dd><p>25/1
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>sntsc</samp>’</span></dt>
|
||
|
|
<dd><p>30000/1001
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>spal</samp>’</span></dt>
|
||
|
|
<dd><p>25/1
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>film</samp>’</span></dt>
|
||
|
|
<dd><p>24/1
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>ntsc-film</samp>’</span></dt>
|
||
|
|
<dd><p>24000/1001
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<span id="ratio-syntax"></span><a name="Ratio"></a>
|
||
|
|
<h3 class="section">2.6 Ratio<span class="pull-right"><a class="anchor hidden-xs" href="#Ratio" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Ratio" aria-hidden="true">TOC</a></span></h3>
|
||
|
|
|
||
|
|
<p>A ratio can be expressed as an expression, or in the form
|
||
|
|
<var>numerator</var>:<var>denominator</var>.
|
||
|
|
</p>
|
||
|
|
<p>Note that a ratio with infinite (1/0) or negative value is
|
||
|
|
considered valid, so you should check on the returned value if you
|
||
|
|
want to exclude those values.
|
||
|
|
</p>
|
||
|
|
<p>The undefined value can be expressed using the "0:0" string.
|
||
|
|
</p>
|
||
|
|
<span id="color-syntax"></span><a name="Color"></a>
|
||
|
|
<h3 class="section">2.7 Color<span class="pull-right"><a class="anchor hidden-xs" href="#Color" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Color" aria-hidden="true">TOC</a></span></h3>
|
||
|
|
|
||
|
|
<p>It can be the name of a color as defined below (case insensitive match) or a
|
||
|
|
<code>[0x|#]RRGGBB[AA]</code> sequence, possibly followed by @ and a string
|
||
|
|
representing the alpha component.
|
||
|
|
</p>
|
||
|
|
<p>The alpha component may be a string composed by "0x" followed by an
|
||
|
|
hexadecimal number or a decimal number between 0.0 and 1.0, which
|
||
|
|
represents the opacity value (‘<samp>0x00</samp>’ or ‘<samp>0.0</samp>’ means completely
|
||
|
|
transparent, ‘<samp>0xff</samp>’ or ‘<samp>1.0</samp>’ completely opaque). If the alpha
|
||
|
|
component is not specified then ‘<samp>0xff</samp>’ is assumed.
|
||
|
|
</p>
|
||
|
|
<p>The string ‘<samp>random</samp>’ will result in a random color.
|
||
|
|
</p>
|
||
|
|
<p>The following names of colors are recognized:
|
||
|
|
</p><dl compact="compact">
|
||
|
|
<dt><span>‘<samp>AliceBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0xF0F8FF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>AntiqueWhite</samp>’</span></dt>
|
||
|
|
<dd><p>0xFAEBD7
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Aqua</samp>’</span></dt>
|
||
|
|
<dd><p>0x00FFFF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Aquamarine</samp>’</span></dt>
|
||
|
|
<dd><p>0x7FFFD4
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Azure</samp>’</span></dt>
|
||
|
|
<dd><p>0xF0FFFF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Beige</samp>’</span></dt>
|
||
|
|
<dd><p>0xF5F5DC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Bisque</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFE4C4
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Black</samp>’</span></dt>
|
||
|
|
<dd><p>0x000000
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>BlanchedAlmond</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFEBCD
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Blue</samp>’</span></dt>
|
||
|
|
<dd><p>0x0000FF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>BlueViolet</samp>’</span></dt>
|
||
|
|
<dd><p>0x8A2BE2
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Brown</samp>’</span></dt>
|
||
|
|
<dd><p>0xA52A2A
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>BurlyWood</samp>’</span></dt>
|
||
|
|
<dd><p>0xDEB887
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>CadetBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x5F9EA0
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Chartreuse</samp>’</span></dt>
|
||
|
|
<dd><p>0x7FFF00
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Chocolate</samp>’</span></dt>
|
||
|
|
<dd><p>0xD2691E
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Coral</samp>’</span></dt>
|
||
|
|
<dd><p>0xFF7F50
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>CornflowerBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x6495ED
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Cornsilk</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFF8DC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Crimson</samp>’</span></dt>
|
||
|
|
<dd><p>0xDC143C
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Cyan</samp>’</span></dt>
|
||
|
|
<dd><p>0x00FFFF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x00008B
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkCyan</samp>’</span></dt>
|
||
|
|
<dd><p>0x008B8B
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkGoldenRod</samp>’</span></dt>
|
||
|
|
<dd><p>0xB8860B
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkGray</samp>’</span></dt>
|
||
|
|
<dd><p>0xA9A9A9
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x006400
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkKhaki</samp>’</span></dt>
|
||
|
|
<dd><p>0xBDB76B
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkMagenta</samp>’</span></dt>
|
||
|
|
<dd><p>0x8B008B
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkOliveGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x556B2F
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Darkorange</samp>’</span></dt>
|
||
|
|
<dd><p>0xFF8C00
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkOrchid</samp>’</span></dt>
|
||
|
|
<dd><p>0x9932CC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkRed</samp>’</span></dt>
|
||
|
|
<dd><p>0x8B0000
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkSalmon</samp>’</span></dt>
|
||
|
|
<dd><p>0xE9967A
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkSeaGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x8FBC8F
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkSlateBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x483D8B
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkSlateGray</samp>’</span></dt>
|
||
|
|
<dd><p>0x2F4F4F
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkTurquoise</samp>’</span></dt>
|
||
|
|
<dd><p>0x00CED1
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DarkViolet</samp>’</span></dt>
|
||
|
|
<dd><p>0x9400D3
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DeepPink</samp>’</span></dt>
|
||
|
|
<dd><p>0xFF1493
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DeepSkyBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x00BFFF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DimGray</samp>’</span></dt>
|
||
|
|
<dd><p>0x696969
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DodgerBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x1E90FF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>FireBrick</samp>’</span></dt>
|
||
|
|
<dd><p>0xB22222
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>FloralWhite</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFFAF0
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>ForestGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x228B22
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Fuchsia</samp>’</span></dt>
|
||
|
|
<dd><p>0xFF00FF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Gainsboro</samp>’</span></dt>
|
||
|
|
<dd><p>0xDCDCDC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>GhostWhite</samp>’</span></dt>
|
||
|
|
<dd><p>0xF8F8FF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Gold</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFD700
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>GoldenRod</samp>’</span></dt>
|
||
|
|
<dd><p>0xDAA520
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Gray</samp>’</span></dt>
|
||
|
|
<dd><p>0x808080
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Green</samp>’</span></dt>
|
||
|
|
<dd><p>0x008000
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>GreenYellow</samp>’</span></dt>
|
||
|
|
<dd><p>0xADFF2F
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>HoneyDew</samp>’</span></dt>
|
||
|
|
<dd><p>0xF0FFF0
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>HotPink</samp>’</span></dt>
|
||
|
|
<dd><p>0xFF69B4
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>IndianRed</samp>’</span></dt>
|
||
|
|
<dd><p>0xCD5C5C
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Indigo</samp>’</span></dt>
|
||
|
|
<dd><p>0x4B0082
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Ivory</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFFFF0
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Khaki</samp>’</span></dt>
|
||
|
|
<dd><p>0xF0E68C
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Lavender</samp>’</span></dt>
|
||
|
|
<dd><p>0xE6E6FA
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LavenderBlush</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFF0F5
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LawnGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x7CFC00
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LemonChiffon</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFFACD
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0xADD8E6
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightCoral</samp>’</span></dt>
|
||
|
|
<dd><p>0xF08080
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightCyan</samp>’</span></dt>
|
||
|
|
<dd><p>0xE0FFFF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightGoldenRodYellow</samp>’</span></dt>
|
||
|
|
<dd><p>0xFAFAD2
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x90EE90
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightGrey</samp>’</span></dt>
|
||
|
|
<dd><p>0xD3D3D3
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightPink</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFB6C1
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightSalmon</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFA07A
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightSeaGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x20B2AA
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightSkyBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x87CEFA
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightSlateGray</samp>’</span></dt>
|
||
|
|
<dd><p>0x778899
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightSteelBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0xB0C4DE
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LightYellow</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFFFE0
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Lime</samp>’</span></dt>
|
||
|
|
<dd><p>0x00FF00
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LimeGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x32CD32
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Linen</samp>’</span></dt>
|
||
|
|
<dd><p>0xFAF0E6
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Magenta</samp>’</span></dt>
|
||
|
|
<dd><p>0xFF00FF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Maroon</samp>’</span></dt>
|
||
|
|
<dd><p>0x800000
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MediumAquaMarine</samp>’</span></dt>
|
||
|
|
<dd><p>0x66CDAA
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MediumBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x0000CD
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MediumOrchid</samp>’</span></dt>
|
||
|
|
<dd><p>0xBA55D3
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MediumPurple</samp>’</span></dt>
|
||
|
|
<dd><p>0x9370D8
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MediumSeaGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x3CB371
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MediumSlateBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x7B68EE
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MediumSpringGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x00FA9A
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MediumTurquoise</samp>’</span></dt>
|
||
|
|
<dd><p>0x48D1CC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MediumVioletRed</samp>’</span></dt>
|
||
|
|
<dd><p>0xC71585
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MidnightBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x191970
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MintCream</samp>’</span></dt>
|
||
|
|
<dd><p>0xF5FFFA
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>MistyRose</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFE4E1
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Moccasin</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFE4B5
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>NavajoWhite</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFDEAD
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Navy</samp>’</span></dt>
|
||
|
|
<dd><p>0x000080
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>OldLace</samp>’</span></dt>
|
||
|
|
<dd><p>0xFDF5E6
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Olive</samp>’</span></dt>
|
||
|
|
<dd><p>0x808000
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>OliveDrab</samp>’</span></dt>
|
||
|
|
<dd><p>0x6B8E23
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Orange</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFA500
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>OrangeRed</samp>’</span></dt>
|
||
|
|
<dd><p>0xFF4500
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Orchid</samp>’</span></dt>
|
||
|
|
<dd><p>0xDA70D6
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>PaleGoldenRod</samp>’</span></dt>
|
||
|
|
<dd><p>0xEEE8AA
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>PaleGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x98FB98
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>PaleTurquoise</samp>’</span></dt>
|
||
|
|
<dd><p>0xAFEEEE
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>PaleVioletRed</samp>’</span></dt>
|
||
|
|
<dd><p>0xD87093
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>PapayaWhip</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFEFD5
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>PeachPuff</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFDAB9
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Peru</samp>’</span></dt>
|
||
|
|
<dd><p>0xCD853F
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Pink</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFC0CB
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Plum</samp>’</span></dt>
|
||
|
|
<dd><p>0xDDA0DD
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>PowderBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0xB0E0E6
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Purple</samp>’</span></dt>
|
||
|
|
<dd><p>0x800080
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Red</samp>’</span></dt>
|
||
|
|
<dd><p>0xFF0000
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>RosyBrown</samp>’</span></dt>
|
||
|
|
<dd><p>0xBC8F8F
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>RoyalBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x4169E1
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SaddleBrown</samp>’</span></dt>
|
||
|
|
<dd><p>0x8B4513
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Salmon</samp>’</span></dt>
|
||
|
|
<dd><p>0xFA8072
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SandyBrown</samp>’</span></dt>
|
||
|
|
<dd><p>0xF4A460
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SeaGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x2E8B57
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SeaShell</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFF5EE
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Sienna</samp>’</span></dt>
|
||
|
|
<dd><p>0xA0522D
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Silver</samp>’</span></dt>
|
||
|
|
<dd><p>0xC0C0C0
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SkyBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x87CEEB
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SlateBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x6A5ACD
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SlateGray</samp>’</span></dt>
|
||
|
|
<dd><p>0x708090
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Snow</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFFAFA
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SpringGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x00FF7F
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SteelBlue</samp>’</span></dt>
|
||
|
|
<dd><p>0x4682B4
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Tan</samp>’</span></dt>
|
||
|
|
<dd><p>0xD2B48C
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Teal</samp>’</span></dt>
|
||
|
|
<dd><p>0x008080
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Thistle</samp>’</span></dt>
|
||
|
|
<dd><p>0xD8BFD8
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Tomato</samp>’</span></dt>
|
||
|
|
<dd><p>0xFF6347
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Turquoise</samp>’</span></dt>
|
||
|
|
<dd><p>0x40E0D0
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Violet</samp>’</span></dt>
|
||
|
|
<dd><p>0xEE82EE
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Wheat</samp>’</span></dt>
|
||
|
|
<dd><p>0xF5DEB3
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>White</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFFFFF
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>WhiteSmoke</samp>’</span></dt>
|
||
|
|
<dd><p>0xF5F5F5
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>Yellow</samp>’</span></dt>
|
||
|
|
<dd><p>0xFFFF00
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>YellowGreen</samp>’</span></dt>
|
||
|
|
<dd><p>0x9ACD32
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<span id="channel-layout-syntax"></span><a name="Channel-Layout"></a>
|
||
|
|
<h3 class="section">2.8 Channel Layout<span class="pull-right"><a class="anchor hidden-xs" href="#Channel-Layout" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Channel-Layout" aria-hidden="true">TOC</a></span></h3>
|
||
|
|
|
||
|
|
<p>A channel layout specifies the spatial disposition of the channels in
|
||
|
|
a multi-channel audio stream. To specify a channel layout, FFmpeg
|
||
|
|
makes use of a special syntax.
|
||
|
|
</p>
|
||
|
|
<p>Individual channels are identified by an id, as given by the table
|
||
|
|
below:
|
||
|
|
</p><dl compact="compact">
|
||
|
|
<dt><span>‘<samp>FL</samp>’</span></dt>
|
||
|
|
<dd><p>front left
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>FR</samp>’</span></dt>
|
||
|
|
<dd><p>front right
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>FC</samp>’</span></dt>
|
||
|
|
<dd><p>front center
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LFE</samp>’</span></dt>
|
||
|
|
<dd><p>low frequency
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>BL</samp>’</span></dt>
|
||
|
|
<dd><p>back left
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>BR</samp>’</span></dt>
|
||
|
|
<dd><p>back right
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>FLC</samp>’</span></dt>
|
||
|
|
<dd><p>front left-of-center
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>FRC</samp>’</span></dt>
|
||
|
|
<dd><p>front right-of-center
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>BC</samp>’</span></dt>
|
||
|
|
<dd><p>back center
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SL</samp>’</span></dt>
|
||
|
|
<dd><p>side left
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SR</samp>’</span></dt>
|
||
|
|
<dd><p>side right
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>TC</samp>’</span></dt>
|
||
|
|
<dd><p>top center
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>TFL</samp>’</span></dt>
|
||
|
|
<dd><p>top front left
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>TFC</samp>’</span></dt>
|
||
|
|
<dd><p>top front center
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>TFR</samp>’</span></dt>
|
||
|
|
<dd><p>top front right
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>TBL</samp>’</span></dt>
|
||
|
|
<dd><p>top back left
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>TBC</samp>’</span></dt>
|
||
|
|
<dd><p>top back center
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>TBR</samp>’</span></dt>
|
||
|
|
<dd><p>top back right
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DL</samp>’</span></dt>
|
||
|
|
<dd><p>downmix left
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>DR</samp>’</span></dt>
|
||
|
|
<dd><p>downmix right
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>WL</samp>’</span></dt>
|
||
|
|
<dd><p>wide left
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>WR</samp>’</span></dt>
|
||
|
|
<dd><p>wide right
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SDL</samp>’</span></dt>
|
||
|
|
<dd><p>surround direct left
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>SDR</samp>’</span></dt>
|
||
|
|
<dd><p>surround direct right
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>LFE2</samp>’</span></dt>
|
||
|
|
<dd><p>low frequency 2
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>Standard channel layout compositions can be specified by using the
|
||
|
|
following identifiers:
|
||
|
|
</p><dl compact="compact">
|
||
|
|
<dt><span>‘<samp>mono</samp>’</span></dt>
|
||
|
|
<dd><p>FC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>stereo</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>2.1</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+LFE
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>3.0</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>3.0(back)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+BC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>4.0</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+BC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>quad</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+BL+BR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>quad(side)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>3.1</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>5.0</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+BL+BR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>5.0(side)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>4.1</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+BC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>5.1</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+BL+BR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>5.1(side)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>6.0</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+BC+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>6.0(front)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FLC+FRC+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>hexagonal</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+BL+BR+BC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>6.1</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+BC+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>6.1</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+BL+BR+BC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>6.1(front)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+LFE+FLC+FRC+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>7.0</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+BL+BR+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>7.0(front)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+FLC+FRC+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>7.1</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+BL+BR+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>7.1(wide)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+BL+BR+FLC+FRC
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>7.1(wide-side)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+FLC+FRC+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>7.1(top)</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+BL+BR+TFL+TFR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>octagonal</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+BL+BR+BC+SL+SR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>cube</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+BL+BR+TFL+TFR+TBL+TBR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>hexadecagonal</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+BL+BR+BC+SL+SR+WL+WR+TBL+TBR+TBC+TFC+TFL+TFR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>downmix</samp>’</span></dt>
|
||
|
|
<dd><p>DL+DR
|
||
|
|
</p></dd>
|
||
|
|
<dt><span>‘<samp>22.2</samp>’</span></dt>
|
||
|
|
<dd><p>FL+FR+FC+LFE+BL+BR+FLC+FRC+BC+SL+SR+TC+TFL+TFC+TFR+TBL+TBC+TBR+LFE2+TSL+TSR+BFC+BFL+BFR
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>A custom channel layout can be specified as a sequence of terms, separated by ’+’.
|
||
|
|
Each term can be:
|
||
|
|
</p><ul>
|
||
|
|
<li> the name of a single channel (e.g. ‘<samp>FL</samp>’, ‘<samp>FR</samp>’, ‘<samp>FC</samp>’, ‘<samp>LFE</samp>’, etc.),
|
||
|
|
each optionally containing a custom name after a ’@’, (e.g. ‘<samp>FL@Left</samp>’,
|
||
|
|
‘<samp>FR@Right</samp>’, ‘<samp>FC@Center</samp>’, ‘<samp>LFE@Low_Frequency</samp>’, etc.)
|
||
|
|
</li></ul>
|
||
|
|
|
||
|
|
<p>A standard channel layout can be specified by the following:
|
||
|
|
</p><ul>
|
||
|
|
<li> the name of a single channel (e.g. ‘<samp>FL</samp>’, ‘<samp>FR</samp>’, ‘<samp>FC</samp>’, ‘<samp>LFE</samp>’, etc.)
|
||
|
|
|
||
|
|
</li><li> the name of a standard channel layout (e.g. ‘<samp>mono</samp>’,
|
||
|
|
‘<samp>stereo</samp>’, ‘<samp>4.0</samp>’, ‘<samp>quad</samp>’, ‘<samp>5.0</samp>’, etc.)
|
||
|
|
|
||
|
|
</li><li> a number of channels, in decimal, followed by ’c’, yielding the default channel
|
||
|
|
layout for that number of channels (see the function
|
||
|
|
<code>av_channel_layout_default</code>). Note that not all channel counts have a
|
||
|
|
default layout.
|
||
|
|
|
||
|
|
</li><li> a number of channels, in decimal, followed by ’C’, yielding an unknown channel
|
||
|
|
layout with the specified number of channels. Note that not all channel layout
|
||
|
|
specification strings support unknown channel layouts.
|
||
|
|
|
||
|
|
</li><li> a channel layout mask, in hexadecimal starting with "0x" (see the
|
||
|
|
<code>AV_CH_*</code> macros in <samp>libavutil/channel_layout.h</samp>.
|
||
|
|
</li></ul>
|
||
|
|
|
||
|
|
<p>Before libavutil version 53 the trailing character "c" to specify a number of
|
||
|
|
channels was optional, but now it is required, while a channel layout mask can
|
||
|
|
also be specified as a decimal number (if and only if not followed by "c" or "C").
|
||
|
|
</p>
|
||
|
|
<p>See also the function <code>av_channel_layout_from_string</code> defined in
|
||
|
|
<samp>libavutil/channel_layout.h</samp>.
|
||
|
|
</p>
|
||
|
|
<a name="Expression-Evaluation"></a>
|
||
|
|
<h2 class="chapter">3 Expression Evaluation<span class="pull-right"><a class="anchor hidden-xs" href="#Expression-Evaluation" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Expression-Evaluation" aria-hidden="true">TOC</a></span></h2>
|
||
|
|
|
||
|
|
<p>When evaluating an arithmetic expression, FFmpeg uses an internal
|
||
|
|
formula evaluator, implemented through the <samp>libavutil/eval.h</samp>
|
||
|
|
interface.
|
||
|
|
</p>
|
||
|
|
<p>An expression may contain unary, binary operators, constants, and
|
||
|
|
functions.
|
||
|
|
</p>
|
||
|
|
<p>Two expressions <var>expr1</var> and <var>expr2</var> can be combined to form
|
||
|
|
another expression "<var>expr1</var>;<var>expr2</var>".
|
||
|
|
<var>expr1</var> and <var>expr2</var> are evaluated in turn, and the new
|
||
|
|
expression evaluates to the value of <var>expr2</var>.
|
||
|
|
</p>
|
||
|
|
<p>The following binary operators are available: <code>+</code>, <code>-</code>,
|
||
|
|
<code>*</code>, <code>/</code>, <code>^</code>.
|
||
|
|
</p>
|
||
|
|
<p>The following unary operators are available: <code>+</code>, <code>-</code>.
|
||
|
|
</p>
|
||
|
|
<p>The following functions are available:
|
||
|
|
</p><dl compact="compact">
|
||
|
|
<dt><span><samp>abs(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute absolute value of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>acos(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute arccosine of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>asin(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute arcsine of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>atan(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute arctangent of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>atan2(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Compute principal value of the arc tangent of <var>y</var>/<var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>between(x, min, max)</samp></span></dt>
|
||
|
|
<dd><p>Return 1 if <var>x</var> is greater than or equal to <var>min</var> and lesser than or
|
||
|
|
equal to <var>max</var>, 0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>bitand(x, y)</samp></span></dt>
|
||
|
|
<dt><span><samp>bitor(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Compute bitwise and/or operation on <var>x</var> and <var>y</var>.
|
||
|
|
</p>
|
||
|
|
<p>The results of the evaluation of <var>x</var> and <var>y</var> are converted to
|
||
|
|
integers before executing the bitwise operation.
|
||
|
|
</p>
|
||
|
|
<p>Note that both the conversion to integer and the conversion back to
|
||
|
|
floating point can lose precision. Beware of unexpected results for
|
||
|
|
large numbers (usually 2^53 and larger).
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>ceil(expr)</samp></span></dt>
|
||
|
|
<dd><p>Round the value of expression <var>expr</var> upwards to the nearest
|
||
|
|
integer. For example, "ceil(1.5)" is "2.0".
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>clip(x, min, max)</samp></span></dt>
|
||
|
|
<dd><p>Return the value of <var>x</var> clipped between <var>min</var> and <var>max</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>cos(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute cosine of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>cosh(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute hyperbolic cosine of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>eq(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Return 1 if <var>x</var> and <var>y</var> are equivalent, 0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>exp(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute exponential of <var>x</var> (with base <code>e</code>, the Euler’s number).
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>floor(expr)</samp></span></dt>
|
||
|
|
<dd><p>Round the value of expression <var>expr</var> downwards to the nearest
|
||
|
|
integer. For example, "floor(-1.5)" is "-2.0".
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>gauss(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute Gauss function of <var>x</var>, corresponding to
|
||
|
|
<code>exp(-x*x/2) / sqrt(2*PI)</code>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>gcd(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Return the greatest common divisor of <var>x</var> and <var>y</var>. If both <var>x</var> and
|
||
|
|
<var>y</var> are 0 or either or both are less than zero then behavior is undefined.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>gt(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Return 1 if <var>x</var> is greater than <var>y</var>, 0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>gte(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Return 1 if <var>x</var> is greater than or equal to <var>y</var>, 0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>hypot(x, y)</samp></span></dt>
|
||
|
|
<dd><p>This function is similar to the C function with the same name; it returns
|
||
|
|
"sqrt(<var>x</var>*<var>x</var> + <var>y</var>*<var>y</var>)", the length of the hypotenuse of a
|
||
|
|
right triangle with sides of length <var>x</var> and <var>y</var>, or the distance of the
|
||
|
|
point (<var>x</var>, <var>y</var>) from the origin.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>if(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Evaluate <var>x</var>, and if the result is non-zero return the result of
|
||
|
|
the evaluation of <var>y</var>, return 0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>if(x, y, z)</samp></span></dt>
|
||
|
|
<dd><p>Evaluate <var>x</var>, and if the result is non-zero return the evaluation
|
||
|
|
result of <var>y</var>, otherwise the evaluation result of <var>z</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>ifnot(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Evaluate <var>x</var>, and if the result is zero return the result of the
|
||
|
|
evaluation of <var>y</var>, return 0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>ifnot(x, y, z)</samp></span></dt>
|
||
|
|
<dd><p>Evaluate <var>x</var>, and if the result is zero return the evaluation
|
||
|
|
result of <var>y</var>, otherwise the evaluation result of <var>z</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>isinf(x)</samp></span></dt>
|
||
|
|
<dd><p>Return 1.0 if <var>x</var> is +/-INFINITY, 0.0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>isnan(x)</samp></span></dt>
|
||
|
|
<dd><p>Return 1.0 if <var>x</var> is NAN, 0.0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>ld(var)</samp></span></dt>
|
||
|
|
<dd><p>Load the value of the internal variable with number
|
||
|
|
<var>var</var>, which was previously stored with st(<var>var</var>, <var>expr</var>).
|
||
|
|
The function returns the loaded value.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>lerp(x, y, z)</samp></span></dt>
|
||
|
|
<dd><p>Return linear interpolation between <var>x</var> and <var>y</var> by amount of <var>z</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>log(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute natural logarithm of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>lt(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Return 1 if <var>x</var> is lesser than <var>y</var>, 0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>lte(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Return 1 if <var>x</var> is lesser than or equal to <var>y</var>, 0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>max(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Return the maximum between <var>x</var> and <var>y</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>min(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Return the minimum between <var>x</var> and <var>y</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>mod(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Compute the remainder of division of <var>x</var> by <var>y</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>not(expr)</samp></span></dt>
|
||
|
|
<dd><p>Return 1.0 if <var>expr</var> is zero, 0.0 otherwise.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>pow(x, y)</samp></span></dt>
|
||
|
|
<dd><p>Compute the power of <var>x</var> elevated <var>y</var>, it is equivalent to
|
||
|
|
"(<var>x</var>)^(<var>y</var>)".
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>print(t)</samp></span></dt>
|
||
|
|
<dt><span><samp>print(t, l)</samp></span></dt>
|
||
|
|
<dd><p>Print the value of expression <var>t</var> with loglevel <var>l</var>. If
|
||
|
|
<var>l</var> is not specified then a default log level is used.
|
||
|
|
Returns the value of the expression printed.
|
||
|
|
</p>
|
||
|
|
<p>Prints t with loglevel l
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>random(x)</samp></span></dt>
|
||
|
|
<dd><p>Return a pseudo random value between 0.0 and 1.0. <var>x</var> is the index of the
|
||
|
|
internal variable which will be used to save the seed/state.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>root(expr, max)</samp></span></dt>
|
||
|
|
<dd><p>Find an input value for which the function represented by <var>expr</var>
|
||
|
|
with argument <var>ld(0)</var> is 0 in the interval 0..<var>max</var>.
|
||
|
|
</p>
|
||
|
|
<p>The expression in <var>expr</var> must denote a continuous function or the
|
||
|
|
result is undefined.
|
||
|
|
</p>
|
||
|
|
<p><var>ld(0)</var> is used to represent the function input value, which means
|
||
|
|
that the given expression will be evaluated multiple times with
|
||
|
|
various input values that the expression can access through
|
||
|
|
<code>ld(0)</code>. When the expression evaluates to 0 then the
|
||
|
|
corresponding input value will be returned.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>round(expr)</samp></span></dt>
|
||
|
|
<dd><p>Round the value of expression <var>expr</var> to the nearest integer. For example, "round(1.5)" is "2.0".
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>sgn(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute sign of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>sin(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute sine of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>sinh(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute hyperbolic sine of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>sqrt(expr)</samp></span></dt>
|
||
|
|
<dd><p>Compute the square root of <var>expr</var>. This is equivalent to
|
||
|
|
"(<var>expr</var>)^.5".
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>squish(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute expression <code>1/(1 + exp(4*x))</code>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>st(var, expr)</samp></span></dt>
|
||
|
|
<dd><p>Store the value of the expression <var>expr</var> in an internal
|
||
|
|
variable. <var>var</var> specifies the number of the variable where to
|
||
|
|
store the value, and it is a value ranging from 0 to 9. The function
|
||
|
|
returns the value stored in the internal variable.
|
||
|
|
Note, Variables are currently not shared between expressions.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>tan(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute tangent of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>tanh(x)</samp></span></dt>
|
||
|
|
<dd><p>Compute hyperbolic tangent of <var>x</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>taylor(expr, x)</samp></span></dt>
|
||
|
|
<dt><span><samp>taylor(expr, x, id)</samp></span></dt>
|
||
|
|
<dd><p>Evaluate a Taylor series at <var>x</var>, given an expression representing
|
||
|
|
the <code>ld(id)</code>-th derivative of a function at 0.
|
||
|
|
</p>
|
||
|
|
<p>When the series does not converge the result is undefined.
|
||
|
|
</p>
|
||
|
|
<p><var>ld(id)</var> is used to represent the derivative order in <var>expr</var>,
|
||
|
|
which means that the given expression will be evaluated multiple times
|
||
|
|
with various input values that the expression can access through
|
||
|
|
<code>ld(id)</code>. If <var>id</var> is not specified then 0 is assumed.
|
||
|
|
</p>
|
||
|
|
<p>Note, when you have the derivatives at y instead of 0,
|
||
|
|
<code>taylor(expr, x-y)</code> can be used.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>time(0)</samp></span></dt>
|
||
|
|
<dd><p>Return the current (wallclock) time in seconds.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>trunc(expr)</samp></span></dt>
|
||
|
|
<dd><p>Round the value of expression <var>expr</var> towards zero to the nearest
|
||
|
|
integer. For example, "trunc(-1.5)" is "-1.0".
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><span><samp>while(cond, expr)</samp></span></dt>
|
||
|
|
<dd><p>Evaluate expression <var>expr</var> while the expression <var>cond</var> is
|
||
|
|
non-zero, and returns the value of the last <var>expr</var> evaluation, or
|
||
|
|
NAN if <var>cond</var> was always false.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>The following constants are available:
|
||
|
|
</p><dl compact="compact">
|
||
|
|
<dt><span><samp>PI</samp></span></dt>
|
||
|
|
<dd><p>area of the unit disc, approximately 3.14
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>E</samp></span></dt>
|
||
|
|
<dd><p>exp(1) (Euler’s number), approximately 2.718
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>PHI</samp></span></dt>
|
||
|
|
<dd><p>golden ratio (1+sqrt(5))/2, approximately 1.618
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>Assuming that an expression is considered "true" if it has a non-zero
|
||
|
|
value, note that:
|
||
|
|
</p>
|
||
|
|
<p><code>*</code> works like AND
|
||
|
|
</p>
|
||
|
|
<p><code>+</code> works like OR
|
||
|
|
</p>
|
||
|
|
<p>For example the construct:
|
||
|
|
</p><div class="example">
|
||
|
|
<pre class="example">if (A AND B) then C
|
||
|
|
</pre></div>
|
||
|
|
<p>is equivalent to:
|
||
|
|
</p><div class="example">
|
||
|
|
<pre class="example">if(A*B, C)
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>In your C code, you can extend the list of unary and binary functions,
|
||
|
|
and define recognized constants, so that they are available for your
|
||
|
|
expressions.
|
||
|
|
</p>
|
||
|
|
<p>The evaluator also recognizes the International System unit prefixes.
|
||
|
|
If ’i’ is appended after the prefix, binary prefixes are used, which
|
||
|
|
are based on powers of 1024 instead of powers of 1000.
|
||
|
|
The ’B’ postfix multiplies the value by 8, and can be appended after a
|
||
|
|
unit prefix or used alone. This allows using for example ’KB’, ’MiB’,
|
||
|
|
’G’ and ’B’ as number postfix.
|
||
|
|
</p>
|
||
|
|
<p>The list of available International System prefixes follows, with
|
||
|
|
indication of the corresponding powers of 10 and of 2.
|
||
|
|
</p><dl compact="compact">
|
||
|
|
<dt><span><samp>y</samp></span></dt>
|
||
|
|
<dd><p>10^-24 / 2^-80
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>z</samp></span></dt>
|
||
|
|
<dd><p>10^-21 / 2^-70
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>a</samp></span></dt>
|
||
|
|
<dd><p>10^-18 / 2^-60
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>f</samp></span></dt>
|
||
|
|
<dd><p>10^-15 / 2^-50
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>p</samp></span></dt>
|
||
|
|
<dd><p>10^-12 / 2^-40
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>n</samp></span></dt>
|
||
|
|
<dd><p>10^-9 / 2^-30
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>u</samp></span></dt>
|
||
|
|
<dd><p>10^-6 / 2^-20
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>m</samp></span></dt>
|
||
|
|
<dd><p>10^-3 / 2^-10
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>c</samp></span></dt>
|
||
|
|
<dd><p>10^-2
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>d</samp></span></dt>
|
||
|
|
<dd><p>10^-1
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>h</samp></span></dt>
|
||
|
|
<dd><p>10^2
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>k</samp></span></dt>
|
||
|
|
<dd><p>10^3 / 2^10
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>K</samp></span></dt>
|
||
|
|
<dd><p>10^3 / 2^10
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>M</samp></span></dt>
|
||
|
|
<dd><p>10^6 / 2^20
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>G</samp></span></dt>
|
||
|
|
<dd><p>10^9 / 2^30
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>T</samp></span></dt>
|
||
|
|
<dd><p>10^12 / 2^40
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>P</samp></span></dt>
|
||
|
|
<dd><p>10^15 / 2^50
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>E</samp></span></dt>
|
||
|
|
<dd><p>10^18 / 2^60
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>Z</samp></span></dt>
|
||
|
|
<dd><p>10^21 / 2^70
|
||
|
|
</p></dd>
|
||
|
|
<dt><span><samp>Y</samp></span></dt>
|
||
|
|
<dd><p>10^24 / 2^80
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
|
||
|
|
<a name="See-Also"></a>
|
||
|
|
<h2 class="chapter">4 See Also<span class="pull-right"><a class="anchor hidden-xs" href="#See-Also" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-See-Also" aria-hidden="true">TOC</a></span></h2>
|
||
|
|
|
||
|
|
<p><a href="ffmpeg.html">ffmpeg</a>, <a href="ffplay.html">ffplay</a>, <a href="ffprobe.html">ffprobe</a>,
|
||
|
|
<a href="libavutil.html">libavutil</a>
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<a name="Authors"></a>
|
||
|
|
<h2 class="chapter">5 Authors<span class="pull-right"><a class="anchor hidden-xs" href="#Authors" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Authors" aria-hidden="true">TOC</a></span></h2>
|
||
|
|
|
||
|
|
<p>The FFmpeg developers.
|
||
|
|
</p>
|
||
|
|
<p>For details about the authorship, see the Git history of the project
|
||
|
|
(https://git.ffmpeg.org/ffmpeg), e.g. by typing the command
|
||
|
|
<code>git log</code> in the FFmpeg source directory, or browsing the
|
||
|
|
online repository at <a href="https://git.ffmpeg.org/ffmpeg">https://git.ffmpeg.org/ffmpeg</a>.
|
||
|
|
</p>
|
||
|
|
<p>Maintainers for the specific components are listed in the file
|
||
|
|
<samp>MAINTAINERS</samp> in the source code tree.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p style="font-size: small;">
|
||
|
|
This document was generated using <a href="https://www.gnu.org/software/texinfo/"><em>makeinfo</em></a>.
|
||
|
|
</p>
|
||
|
|
</div>
|
||
|
|
</body>
|
||
|
|
</html>
|