267 lines
8.1 KiB
HTML
267 lines
8.1 KiB
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<html>
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<!-- Created by GNU Texinfo 7.0.1, https://www.gnu.org/software/texinfo/ -->
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<title>FFmpeg Scaler Documentation</title>
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<meta name="description" content="FFmpeg Scaler Documentation">
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<meta name="keywords" content="FFmpeg Scaler Documentation">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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<meta name="viewport" content="width=device-width,initial-scale=1">
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<link href="#SEC_Contents" rel="contents" title="Table of Contents">
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<style type="text/css">
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ul.toc-numbered-mark {list-style: none}
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</style>
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</head>
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<body lang="en">
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<div class="top-level-extent" id="SEC_Top">
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<div class="element-contents" 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="toc-numbered-mark">
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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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<div class="chapter-level-extent" id="Description">
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<h2 class="chapter">1 Description</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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<a class="anchor" id="scaler_005foptions"></a></div>
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<div class="chapter-level-extent" id="Scaler-Options">
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<h2 class="chapter">2 Scaler Options</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 class="var">option</var> <var class="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 class="code">SwsContext</code> options or through the <samp class="file">libavutil/opt.h</samp> API.
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</p>
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<dl class="table">
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<dd>
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<a class="anchor" id="sws_005fflags"></a></dd>
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<dt><samp class="option">sws_flags</samp></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 class="samp">bicubic</samp>’.
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</p>
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<p>It accepts the following values:
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</p><dl class="table">
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<dt>‘<samp class="samp">fast_bilinear</samp>’</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>‘<samp class="samp">bilinear</samp>’</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>‘<samp class="samp">bicubic</samp>’</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>‘<samp class="samp">experimental</samp>’</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>‘<samp class="samp">neighbor</samp>’</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>‘<samp class="samp">area</samp>’</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>‘<samp class="samp">bicublin</samp>’</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>‘<samp class="samp">gauss</samp>’</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>‘<samp class="samp">sinc</samp>’</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>‘<samp class="samp">lanczos</samp>’</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 class="code">param0</code>.
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</p>
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</dd>
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<dt>‘<samp class="samp">spline</samp>’</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>‘<samp class="samp">print_info</samp>’</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>‘<samp class="samp">accurate_rnd</samp>’</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>‘<samp class="samp">full_chroma_int</samp>’</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>‘<samp class="samp">full_chroma_inp</samp>’</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>‘<samp class="samp">bitexact</samp>’</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><samp class="option">srcw <var class="var">(API only)</var></samp></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><samp class="option">srch <var class="var">(API only)</var></samp></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><samp class="option">dstw <var class="var">(API only)</var></samp></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><samp class="option">dsth <var class="var">(API only)</var></samp></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><samp class="option">src_format <var class="var">(API only)</var></samp></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><samp class="option">dst_format <var class="var">(API only)</var></samp></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><samp class="option">src_range <var class="var">(boolean)</var></samp></dt>
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<dd><p>If value is set to <code class="code">1</code>, indicates source is full range. Default value is
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<code class="code">0</code>, which indicates source is limited range.
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</p>
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</dd>
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<dt><samp class="option">dst_range <var class="var">(boolean)</var></samp></dt>
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<dd><p>If value is set to <code class="code">1</code>, enable full range for destination. Default value
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is <code class="code">0</code>, which enables limited range.
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</p>
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<a class="anchor" id="sws_005fparams"></a></dd>
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<dt><samp class="option">param0, param1</samp></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><samp class="option">sws_dither</samp></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 class="samp">auto</samp>’.
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</p>
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<dl class="table">
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<dt>‘<samp class="samp">auto</samp>’</dt>
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<dd><p>automatic choice
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</p>
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</dd>
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<dt>‘<samp class="samp">none</samp>’</dt>
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<dd><p>no dithering
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</p>
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</dd>
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<dt>‘<samp class="samp">bayer</samp>’</dt>
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<dd><p>bayer dither
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</p>
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</dd>
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<dt>‘<samp class="samp">ed</samp>’</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>‘<samp class="samp">a_dither</samp>’</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>‘<samp class="samp">x_dither</samp>’</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><samp class="option">alphablend</samp></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 class="samp">none</samp>’.
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</p>
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<dl class="table">
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<dt>‘<samp class="samp">uniform_color</samp>’</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>‘<samp class="samp">checkerboard</samp>’</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>‘<samp class="samp">none</samp>’</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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</div>
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<div class="chapter-level-extent" id="See-Also">
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<h2 class="chapter">3 See Also</h2>
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<p><a class="url" href="ffmpeg.html">ffmpeg</a>, <a class="url" href="ffplay.html">ffplay</a>, <a class="url" href="ffprobe.html">ffprobe</a>,
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<a class="url" href="libswscale.html">libswscale</a>
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</p>
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</div>
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<div class="chapter-level-extent" id="Authors">
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<h2 class="chapter">4 Authors</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 class="command">git log</code> in the FFmpeg source directory, or browsing the
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online repository at <a class="url" 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 class="file">MAINTAINERS</samp> in the source code tree.
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</p>
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</div>
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</div>
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</body>
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</html>
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