257 lines
8.4 KiB
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257 lines
8.4 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<!-- Created by GNU Texinfo 6.8, https://www.gnu.org/software/texinfo/ -->
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<title>
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FFmpeg Scaler 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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<body>
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<div class="container">
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<h1>
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FFmpeg Scaler 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-Scaler-Options" href="#Scaler-Options">2 Scaler Options</a></li>
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<li><a id="toc-See-Also" href="#See-Also">3 See Also</a></li>
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<li><a id="toc-Authors" href="#Authors">4 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>The FFmpeg rescaler provides a high-level interface to the libswscale
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library image conversion utilities. In particular it allows one to perform
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image rescaling and pixel format conversion.
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</p>
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<span id="scaler_005foptions"></span><a name="Scaler-Options"></a>
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<h2 class="chapter">2 Scaler Options<span class="pull-right"><a class="anchor hidden-xs" href="#Scaler-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Scaler-Options" aria-hidden="true">TOC</a></span></h2>
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<p>The video scaler supports the following named options.
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</p>
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<p>Options may be set by specifying -<var>option</var> <var>value</var> in the
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FFmpeg tools, with a few API-only exceptions noted below.
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For programmatic use, they can be set explicitly in the
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<code>SwsContext</code> options or through the <samp>libavutil/opt.h</samp> API.
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</p>
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<dl compact="compact">
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<dd>
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<span id="sws_005fflags"></span></dd>
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<dt><span><samp>sws_flags</samp></span></dt>
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<dd><p>Set the scaler flags. This is also used to set the scaling
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algorithm. Only a single algorithm should be selected. Default
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value is ‘<samp>bicubic</samp>’.
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</p>
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<p>It accepts the following values:
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</p><dl compact="compact">
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<dt><span>‘<samp>fast_bilinear</samp>’</span></dt>
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<dd><p>Select fast bilinear scaling algorithm.
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</p>
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</dd>
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<dt><span>‘<samp>bilinear</samp>’</span></dt>
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<dd><p>Select bilinear scaling algorithm.
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</p>
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</dd>
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<dt><span>‘<samp>bicubic</samp>’</span></dt>
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<dd><p>Select bicubic scaling algorithm.
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</p>
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</dd>
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<dt><span>‘<samp>experimental</samp>’</span></dt>
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<dd><p>Select experimental scaling algorithm.
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</p>
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</dd>
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<dt><span>‘<samp>neighbor</samp>’</span></dt>
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<dd><p>Select nearest neighbor rescaling algorithm.
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</p>
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</dd>
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<dt><span>‘<samp>area</samp>’</span></dt>
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<dd><p>Select averaging area rescaling algorithm.
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</p>
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</dd>
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<dt><span>‘<samp>bicublin</samp>’</span></dt>
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<dd><p>Select bicubic scaling algorithm for the luma component, bilinear for
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chroma components.
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</p>
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</dd>
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<dt><span>‘<samp>gauss</samp>’</span></dt>
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<dd><p>Select Gaussian rescaling algorithm.
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</p>
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</dd>
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<dt><span>‘<samp>sinc</samp>’</span></dt>
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<dd><p>Select sinc rescaling algorithm.
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</p>
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</dd>
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<dt><span>‘<samp>lanczos</samp>’</span></dt>
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<dd><p>Select Lanczos rescaling algorithm. The default width (alpha) is 3 and can be
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changed by setting <code>param0</code>.
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</p>
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</dd>
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<dt><span>‘<samp>spline</samp>’</span></dt>
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<dd><p>Select natural bicubic spline rescaling algorithm.
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</p>
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</dd>
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<dt><span>‘<samp>print_info</samp>’</span></dt>
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<dd><p>Enable printing/debug logging.
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</p>
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</dd>
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<dt><span>‘<samp>accurate_rnd</samp>’</span></dt>
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<dd><p>Enable accurate rounding.
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</p>
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</dd>
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<dt><span>‘<samp>full_chroma_int</samp>’</span></dt>
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<dd><p>Enable full chroma interpolation.
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</p>
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</dd>
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<dt><span>‘<samp>full_chroma_inp</samp>’</span></dt>
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<dd><p>Select full chroma input.
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</p>
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</dd>
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<dt><span>‘<samp>bitexact</samp>’</span></dt>
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<dd><p>Enable bitexact output.
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</p></dd>
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</dl>
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</dd>
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<dt><span><samp>srcw <var>(API only)</var></samp></span></dt>
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<dd><p>Set source width.
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</p>
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</dd>
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<dt><span><samp>srch <var>(API only)</var></samp></span></dt>
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<dd><p>Set source height.
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</p>
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</dd>
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<dt><span><samp>dstw <var>(API only)</var></samp></span></dt>
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<dd><p>Set destination width.
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</p>
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</dd>
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<dt><span><samp>dsth <var>(API only)</var></samp></span></dt>
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<dd><p>Set destination height.
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</p>
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</dd>
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<dt><span><samp>src_format <var>(API only)</var></samp></span></dt>
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<dd><p>Set source pixel format (must be expressed as an integer).
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</p>
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</dd>
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<dt><span><samp>dst_format <var>(API only)</var></samp></span></dt>
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<dd><p>Set destination pixel format (must be expressed as an integer).
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</p>
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</dd>
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<dt><span><samp>src_range <var>(boolean)</var></samp></span></dt>
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<dd><p>If value is set to <code>1</code>, indicates source is full range. Default value is
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<code>0</code>, which indicates source is limited range.
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</p>
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</dd>
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<dt><span><samp>dst_range <var>(boolean)</var></samp></span></dt>
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<dd><p>If value is set to <code>1</code>, enable full range for destination. Default value
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is <code>0</code>, which enables limited range.
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</p>
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<span id="sws_005fparams"></span></dd>
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<dt><span><samp>param0, param1</samp></span></dt>
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<dd><p>Set scaling algorithm parameters. The specified values are specific of
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some scaling algorithms and ignored by others. The specified values
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are floating point number values.
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</p>
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</dd>
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<dt><span><samp>sws_dither</samp></span></dt>
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<dd><p>Set the dithering algorithm. Accepts one of the following
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values. Default value is ‘<samp>auto</samp>’.
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</p>
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<dl compact="compact">
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<dt><span>‘<samp>auto</samp>’</span></dt>
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<dd><p>automatic choice
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</p>
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</dd>
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<dt><span>‘<samp>none</samp>’</span></dt>
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<dd><p>no dithering
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</p>
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</dd>
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<dt><span>‘<samp>bayer</samp>’</span></dt>
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<dd><p>bayer dither
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</p>
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</dd>
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<dt><span>‘<samp>ed</samp>’</span></dt>
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<dd><p>error diffusion dither
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</p>
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</dd>
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<dt><span>‘<samp>a_dither</samp>’</span></dt>
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<dd><p>arithmetic dither, based using addition
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</p>
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</dd>
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<dt><span>‘<samp>x_dither</samp>’</span></dt>
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<dd><p>arithmetic dither, based using xor (more random/less apparent patterning that
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a_dither).
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</p>
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</dd>
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</dl>
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</dd>
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<dt><span><samp>alphablend</samp></span></dt>
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<dd><p>Set the alpha blending to use when the input has alpha but the output does not.
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Default value is ‘<samp>none</samp>’.
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</p>
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<dl compact="compact">
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<dt><span>‘<samp>uniform_color</samp>’</span></dt>
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<dd><p>Blend onto a uniform background color
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</p>
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</dd>
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<dt><span>‘<samp>checkerboard</samp>’</span></dt>
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<dd><p>Blend onto a checkerboard
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</p>
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</dd>
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<dt><span>‘<samp>none</samp>’</span></dt>
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<dd><p>No blending
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</p>
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</dd>
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</dl>
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</dd>
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</dl>
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<a name="See-Also"></a>
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<h2 class="chapter">3 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>
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<p><a href="ffmpeg.html">ffmpeg</a>, <a href="ffplay.html">ffplay</a>, <a href="ffprobe.html">ffprobe</a>,
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<a href="libswscale.html">libswscale</a>
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</p>
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<a name="Authors"></a>
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<h2 class="chapter">4 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>
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<p>The FFmpeg developers.
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</p>
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<p>For details about the authorship, see the Git history of the project
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(https://git.ffmpeg.org/ffmpeg), e.g. by typing the command
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<code>git log</code> in the FFmpeg source directory, or browsing the
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online repository at <a href="https://git.ffmpeg.org/ffmpeg">https://git.ffmpeg.org/ffmpeg</a>.
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</p>
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<p>Maintainers for the specific components are listed in the file
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<samp>MAINTAINERS</samp> in the source code tree.
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</p>
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<p style="font-size: small;">
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This document was generated using <a href="https://www.gnu.org/software/texinfo/"><em>makeinfo</em></a>.
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</p>
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</html>
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