| <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> |
| <html> |
| |
| <head> |
| <meta charset="utf-8"> |
| <title> |
| FFmpeg Scaler Documentation |
| </title> |
| <meta name="viewport" content="width=device-width,initial-scale=1.0"> |
| <link rel="stylesheet" type="text/css" href="bootstrap.min.css"> |
| <link rel="stylesheet" type="text/css" href="style.min.css"> |
| </head> |
| <body> |
| <div class="container"> |
| <h1> |
| FFmpeg Scaler Documentation |
| </h1> |
|
|
|
|
| <a name="SEC_Top"></a> |
|
|
| <div class="element-contents" id="SEC_Contents"> |
| <h2 class="contents-heading">Table of Contents</h2> |
|
|
| <div class="contents"> |
|
|
| <ul class="toc-numbered-mark"> |
| <li><a id="toc-Description" href="#Description">1 Description</a></li> |
| <li><a id="toc-Scaler-Options" href="#Scaler-Options">2 Scaler Options</a></li> |
| <li><a id="toc-See-Also" href="#See-Also">3 See Also</a></li> |
| <li><a id="toc-Authors" href="#Authors">4 Authors</a></li> |
| </ul> |
| </div> |
| </div> |
|
|
| <a name="Description"></a> |
| <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> |
|
|
| <p>The FFmpeg rescaler provides a high-level interface to the libswscale |
| library image conversion utilities. In particular it allows one to perform |
| image rescaling and pixel format conversion. |
| </p> |
|
|
| <a class="anchor" id="scaler_005foptions"></a><a name="Scaler-Options"></a> |
| <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> |
|
|
| <p>The video scaler supports the following named options. |
| </p> |
| <p>Options may be set by specifying -<var class="var">option</var> <var class="var">value</var> in the |
| FFmpeg tools, with a few API-only exceptions noted below. |
| For programmatic use, they can be set explicitly in the |
| <code class="code">SwsContext</code> options or through the <samp class="file">libavutil/opt.h</samp> API. |
| </p> |
| <dl class="table"> |
| <dd> |
| <a class="anchor" id="scaler"></a></dd> |
| <dt><samp class="option">scaler, scaler_sub</samp></dt> |
| <dd><p>Choose the scaling algorithm to use. Default value is ‘<samp class="samp">auto</samp>’ for both. |
| It accepts the following values: |
| </p> |
| <dl class="table"> |
| <dt>‘<samp class="samp">auto</samp>’</dt> |
| <dd><p>Aumotic choice. For ‘<samp class="samp">scaler_sub</samp>’, this means the same algorithm as |
| ‘<samp class="samp">scaler</samp>’. For ‘<samp class="samp">scaler</samp>’, this defaults to the scaler flag selected |
| by ‘<samp class="samp">sws_flags</samp>’. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">bilinear</samp>’</dt> |
| <dd><p>Bilinear filter. (AKA triangle filter) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">bicubic</samp>’</dt> |
| <dd><p>2-tap cubic BC-spline (AKA Mitchell-Netravali spline). The B and C parameters |
| can be configured by setting <code class="code">param0</code> and <code class="code">param1</code>, defaulting to |
| 0.0 and 0.6 respectively. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">point, neighbor</samp>’</dt> |
| <dd><p>Point sampling (AKA nearest neighbor). |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">area</samp>’</dt> |
| <dd><p>Area averaging. Equivalent to ‘<samp class="samp">bilinear</samp>’ for upscaling. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">gaussian</samp>’</dt> |
| <dd><p>2-tap Gaussian filter approximation. The sharpness parameter can be configured |
| by setting <code class="code">param0</code>, defaulting to 3.0. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">sinc</samp>’</dt> |
| <dd><p>Unwindowed sinc filter. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">lanczos</samp>’</dt> |
| <dd><p>Lanczos resampling (sinc windowed sinc). The number of filter taps can |
| be configured by setting <code class="code">param0</code>, defaulting to 3. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">spline</samp>’</dt> |
| <dd><p>Unwindowed natural bicubic spline. |
| </p></dd> |
| </dl> |
|
|
| <a class="anchor" id="sws_005fflags"></a></dd> |
| <dt><samp class="option">sws_flags</samp></dt> |
| <dd><p>Set the scaler flags. This is also used to set the scaling |
| algorithm, though this usage is deprecated in favor of setting ‘<samp class="samp">scaler</samp>’. |
| Only a single algorithm may be selected. Default value is ‘<samp class="samp">bicubic</samp>’. |
| </p> |
| <p>It accepts the following values: |
| </p><dl class="table"> |
| <dt>‘<samp class="samp">fast_bilinear</samp>’</dt> |
| <dd><p>Select fast bilinear scaling algorithm. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">bilinear</samp>’</dt> |
| <dd><p>Select bilinear scaling algorithm. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">bicubic</samp>’</dt> |
| <dd><p>Select bicubic scaling algorithm. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">experimental</samp>’</dt> |
| <dd><p>Select experimental scaling algorithm. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">neighbor</samp>’</dt> |
| <dd><p>Select nearest neighbor rescaling algorithm. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">area</samp>’</dt> |
| <dd><p>Select averaging area rescaling algorithm. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">bicublin</samp>’</dt> |
| <dd><p>Select bicubic scaling algorithm for the luma component, bilinear for |
| chroma components. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">gauss</samp>’</dt> |
| <dd><p>Select Gaussian rescaling algorithm. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">sinc</samp>’</dt> |
| <dd><p>Select sinc rescaling algorithm. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">lanczos</samp>’</dt> |
| <dd><p>Select Lanczos rescaling algorithm. The default width (alpha) is 3 and can be |
| changed by setting <code class="code">param0</code>. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">spline</samp>’</dt> |
| <dd><p>Select natural bicubic spline rescaling algorithm. (Deprecated) |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">print_info</samp>’</dt> |
| <dd><p>Enable printing/debug logging. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">accurate_rnd</samp>’</dt> |
| <dd><p>Enable accurate rounding. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">full_chroma_int</samp>’</dt> |
| <dd><p>Enable full chroma interpolation. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">full_chroma_inp</samp>’</dt> |
| <dd><p>Select full chroma input. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">bitexact</samp>’</dt> |
| <dd><p>Enable bitexact output. |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">unstable</samp>’</dt> |
| <dd><p>Allow the use of experimental new code. May subtly affect the output or even |
| produce wrong results. For testing only. |
| </p></dd> |
| </dl> |
|
|
| </dd> |
| <dt><samp class="option">srcw <var class="var">(API only)</var></samp></dt> |
| <dd><p>Set source width. |
| </p> |
| </dd> |
| <dt><samp class="option">srch <var class="var">(API only)</var></samp></dt> |
| <dd><p>Set source height. |
| </p> |
| </dd> |
| <dt><samp class="option">dstw <var class="var">(API only)</var></samp></dt> |
| <dd><p>Set destination width. |
| </p> |
| </dd> |
| <dt><samp class="option">dsth <var class="var">(API only)</var></samp></dt> |
| <dd><p>Set destination height. |
| </p> |
| </dd> |
| <dt><samp class="option">src_format <var class="var">(API only)</var></samp></dt> |
| <dd><p>Set source pixel format (must be expressed as an integer). |
| </p> |
| </dd> |
| <dt><samp class="option">dst_format <var class="var">(API only)</var></samp></dt> |
| <dd><p>Set destination pixel format (must be expressed as an integer). |
| </p> |
| </dd> |
| <dt><samp class="option">src_range <var class="var">(boolean)</var></samp></dt> |
| <dd><p>If value is set to <code class="code">1</code>, indicates source is full range. Default value is |
| <code class="code">0</code>, which indicates source is limited range. |
| </p> |
| </dd> |
| <dt><samp class="option">dst_range <var class="var">(boolean)</var></samp></dt> |
| <dd><p>If value is set to <code class="code">1</code>, enable full range for destination. Default value |
| is <code class="code">0</code>, which enables limited range. |
| </p> |
| </dd> |
| <dt><samp class="option">gamma <var class="var">(boolean)</var></samp></dt> |
| <dd><p>If value is set to <code class="code">1</code>, enable gamma correct scaling. Default value is <code class="code">0</code>. |
| </p> |
| <a class="anchor" id="sws_005fparams"></a></dd> |
| <dt><samp class="option">param0, param1</samp></dt> |
| <dd><p>Set scaling algorithm parameters. The specified values are specific of |
| some scaling algorithms and ignored by others. The specified values |
| are floating point number values. |
| </p> |
| </dd> |
| <dt><samp class="option">sws_dither</samp></dt> |
| <dd><p>Set the dithering algorithm. Accepts one of the following |
| values. Default value is ‘<samp class="samp">auto</samp>’. |
| </p> |
| <dl class="table"> |
| <dt>‘<samp class="samp">auto</samp>’</dt> |
| <dd><p>automatic choice |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">none</samp>’</dt> |
| <dd><p>no dithering |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">bayer</samp>’</dt> |
| <dd><p>bayer dither |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">ed</samp>’</dt> |
| <dd><p>error diffusion dither |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">a_dither</samp>’</dt> |
| <dd><p>arithmetic dither, based using addition |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">x_dither</samp>’</dt> |
| <dd><p>arithmetic dither, based using xor (more random/less apparent patterning that |
| a_dither). |
| </p> |
| </dd> |
| </dl> |
|
|
| </dd> |
| <dt><samp class="option">alphablend</samp></dt> |
| <dd><p>Set the alpha blending to use when the input has alpha but the output does not. |
| Default value is ‘<samp class="samp">none</samp>’. |
| </p> |
| <dl class="table"> |
| <dt>‘<samp class="samp">uniform_color</samp>’</dt> |
| <dd><p>Blend onto a uniform background color |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">checkerboard</samp>’</dt> |
| <dd><p>Blend onto a checkerboard |
| </p> |
| </dd> |
| <dt>‘<samp class="samp">none</samp>’</dt> |
| <dd><p>No blending |
| </p> |
| </dd> |
| </dl> |
|
|
| </dd> |
| </dl> |
|
|
|
|
| <a name="See-Also"></a> |
| <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> |
|
|
| <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>, |
| <a class="url" href="libswscale.html">libswscale</a> |
| </p> |
|
|
| <a name="Authors"></a> |
| <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> |
|
|
| <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 class="command">git log</code> in the FFmpeg source directory, or browsing the |
| online repository at <a class="url" 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 class="file">MAINTAINERS</samp> in the source code tree. |
| </p> |
|
|
| <p style="font-size: small;"> |
| This document was generated using <a class="uref" href="https://www.gnu.org/software/texinfo/"><em class="emph">makeinfo</em></a>. |
| </p> |
| </div> |
| </body> |
| </html> |
|
|
