mirror of
https://github.com/ahabhyde/miguelbridge
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c835732151
Added support for tg stickers (converted into png images) Fixed a bug in where a tg user without surname would send message with "null" as surname
568 lines
17 KiB
HTML
568 lines
17 KiB
HTML
<!-- Creator : groff version 1.19.2 -->
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<!-- CreationDate: Fri Sep 19 17:51:06 2014 -->
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
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"http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta name="generator" content="groff -Thtml, see www.gnu.org">
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<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
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<meta name="Content-Style" content="text/css">
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<style type="text/css">
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p { margin-top: 0; margin-bottom: 0; }
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pre { margin-top: 0; margin-bottom: 0; }
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table { margin-top: 0; margin-bottom: 0; }
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</style>
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<title>CWEBP</title>
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</head>
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<body>
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<h1 align=center>CWEBP</h1>
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<a href="#NAME">NAME</a><br>
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<a href="#SYNOPSIS">SYNOPSIS</a><br>
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<a href="#DESCRIPTION">DESCRIPTION</a><br>
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<a href="#OPTIONS">OPTIONS</a><br>
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<a href="#ADDITIONAL OPTIONS">ADDITIONAL OPTIONS</a><br>
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<a href="#BUGS">BUGS</a><br>
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<a href="#EXAMPLES">EXAMPLES</a><br>
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<a href="#AUTHORS">AUTHORS</a><br>
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<a href="#SEE ALSO">SEE ALSO</a><br>
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<hr>
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<a name="NAME"></a>
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<h2>NAME</h2>
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<p style="margin-left:11%; margin-top: 1em">cwebp −
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compress an image file to a WebP file</p>
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<a name="SYNOPSIS"></a>
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<h2>SYNOPSIS</h2>
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<p style="margin-left:11%; margin-top: 1em"><b>cwebp</b>
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[<i>options</i>] <i>input_file −o
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output_file.webp</i></p>
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<a name="DESCRIPTION"></a>
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<h2>DESCRIPTION</h2>
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<p style="margin-left:11%; margin-top: 1em">This manual
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page documents the <b>cwebp</b> command.</p>
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<p style="margin-left:11%; margin-top: 1em"><b>cwebp</b>
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compresses an image using the WebP format. Input format can
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be either PNG, JPEG, TIFF, WebP or raw Y’CbCr
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samples.</p>
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<a name="OPTIONS"></a>
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<h2>OPTIONS</h2>
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<p style="margin-left:11%; margin-top: 1em">The basic
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options are: <b><br>
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−o</b> <i>string</i></p>
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<p style="margin-left:22%;">Specify the name of the output
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WebP file. If omitted, <b>cwebp</b> will perform compression
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but only report statistics. Using "−" as
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output name will direct output to ’stdout’.</p>
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<p style="margin-left:11%;"><b>−−</b>
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<i>string</i></p>
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<p style="margin-left:22%;">Explicitly specify the input
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file. This option is useful if the input file starts with an
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’−’ for instance. This option must appear
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<b>last</b>. Any other options afterward will be
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ignored.</p>
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<p style="margin-left:11%;"><b>−h,
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−help</b></p>
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<p style="margin-left:22%;">A short usage summary.</p>
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<p style="margin-left:11%;"><b>−H,
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−longhelp</b></p>
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<p style="margin-left:22%;">A summary of all the possible
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options.</p>
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<p style="margin-left:11%;"><b>−version</b></p>
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<p style="margin-left:22%;">Print the version number (as
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major.minor.revision) and exit.</p>
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<p style="margin-left:11%;"><b>−q</b>
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<i>float</i></p>
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<p style="margin-left:22%;">Specify the compression factor
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for RGB channels between 0 and 100. The default is 75.</p>
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<p style="margin-left:11%;"><b>−alpha_q</b>
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<i>int</i></p>
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<p style="margin-left:22%;">Specify the compression factor
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for alpha compression between 0 and 100. Lossless
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compression of alpha is achieved using a value of 100, while
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the lower values result in a lossy compression. The default
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is 100.</p>
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<table width="100%" border=0 rules="none" frame="void"
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cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="11%"></td>
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<td width="9%">
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<p style="margin-top: 1em" valign="top"><b>−f</b>
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<i>int</i></p> </td>
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<td width="2%"></td>
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<td width="78%">
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<p style="margin-top: 1em" valign="top">Specify the
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strength of the deblocking filter, between 0 (no filtering)
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and 100 (maximum filtering). A value of 0 will turn off any
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filtering. Higher value will increase the strength of the
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filtering process applied after decoding the picture. The
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higher the value the smoother the picture will appear.
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Typical values are usually in the range of 20 to 50.</p></td>
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</table>
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<p style="margin-left:11%;"><b>−preset</b>
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<i>string</i></p>
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<p style="margin-left:22%;">Specify a set of pre-defined
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parameters to suit a particular type of source material.
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Possible values are: <b>default</b>, <b>photo</b>,
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<b>picture</b>, <b>drawing</b>, <b>icon</b>, <b>text</b>.
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Since <b>−preset</b> overwrites the other
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parameters’ values (except the <b>−q</b> one),
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this option should preferably appear first in the order of
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the arguments.</p>
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<p style="margin-left:11%;"><b>−sns</b>
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<i>int</i></p>
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<p style="margin-left:22%;">Specify the amplitude of the
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spatial noise shaping. Spatial noise shaping (or <b>sns</b>
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for short) refers to a general collection of built-in
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algorithms used to decide which area of the picture should
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use relatively less bits, and where else to better transfer
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these bits. The possible range goes from 0 (algorithm is
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off) to 100 (the maximal effect). The default value is
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80.</p>
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<table width="100%" border=0 rules="none" frame="void"
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cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="11%"></td>
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<td width="9%">
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<p style="margin-top: 1em" valign="top"><b>−m</b>
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<i>int</i></p> </td>
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<td width="2%"></td>
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<td width="78%">
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<p style="margin-top: 1em" valign="top">Specify the
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compression method to use. This parameter controls the trade
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off between encoding speed and the compressed file size and
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quality. Possible values range from 0 to 6. Default value is
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4. When higher values are used, the encoder will spend more
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time inspecting additional encoding possibilities and decide
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on the quality gain. Lower value can result in faster
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processing time at the expense of larger file size and lower
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compression quality.</p></td>
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</table>
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<p style="margin-left:11%;"><b>−jpeg_like</b></p>
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<p style="margin-left:22%;">Change the internal parameter
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mapping to better match the expected size of JPEG
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compression. This flag will generally produce an output file
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of similar size to its JPEG equivalent (for the same
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<b>−q</b> setting), but with less visual
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distortion.</p>
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<table width="100%" border=0 rules="none" frame="void"
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cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="11%"></td>
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<td width="4%">
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<p style="margin-top: 1em" valign="top"><b>−mt</b></p> </td>
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<td width="7%"></td>
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<td width="78%">
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<p style="margin-top: 1em" valign="top">Use multi-threading
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for encoding, if possible. This option is only effective
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when using lossy compression on a source with a transparency
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channel.</p> </td>
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</table>
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<p style="margin-left:11%;"><b>−low_memory</b></p>
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<p style="margin-left:22%;">Reduce memory usage of lossy
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encoding by saving four times the compressed size
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(typically). This will make the encoding slower and the
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output slightly different in size and distortion. This flag
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is only effective for methods 3 and up, and is off by
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default. Note that leaving this flag off will have some side
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effects on the bitstream: it forces certain bitstream
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features like number of partitions (forced to 1). Note that
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a more detailed report of bitstream size is printed by
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<b>cwebp</b> when using this option.</p>
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<table width="100%" border=0 rules="none" frame="void"
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cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="11%"></td>
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<td width="4%">
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<p style="margin-top: 1em" valign="top"><b>−af</b></p> </td>
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<td width="7%"></td>
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<td width="78%">
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<p style="margin-top: 1em" valign="top">Turns auto-filter
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on. This algorithm will spend additional time optimizing the
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filtering strength to reach a well-balanced quality.</p></td>
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</table>
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<a name="ADDITIONAL OPTIONS"></a>
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<h2>ADDITIONAL OPTIONS</h2>
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<p style="margin-left:11%; margin-top: 1em">More advanced
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options are: <b><br>
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−sharpness</b> <i>int</i></p>
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<p style="margin-left:22%;">Specify the sharpness of the
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filtering (if used). Range is 0 (sharpest) to 7 (least
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sharp). Default is 0.</p>
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<p style="margin-left:11%;"><b>−strong</b></p>
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<p style="margin-left:22%;">Use strong filtering (if
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filtering is being used thanks to the <b>−f</b>
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option). Strong filtering is on by default.</p>
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<p style="margin-left:11%;"><b>−nostrong</b></p>
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<p style="margin-left:22%;">Disable strong filtering (if
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filtering is being used thanks to the <b>−f</b>
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option) and use simple filtering instead.</p>
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<p style="margin-left:11%;"><b>−segments</b>
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<i>int</i></p>
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<p style="margin-left:22%;">Change the number of partitions
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to use during the segmentation of the sns algorithm.
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Segments should be in range 1 to 4. Default value is 4. This
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option has no effect for methods 3 and up, unless
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<b>−low_memory</b> is used.</p>
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<p style="margin-left:11%;"><b>−partition_limit</b>
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<i>int</i></p>
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<p style="margin-left:22%;">Degrade quality by limiting the
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number of bits used by some macroblocks. Range is 0 (no
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degradation, the default) to 100 (full degradation). Useful
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values are usually around 30-70 for moderately large images.
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In the VP8 format, the so-called control partition has a
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limit of 512k and is used to store the following
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information: whether the macroblock is skipped, which
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segment it belongs to, whether it is coded as intra 4x4 or
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intra 16x16 mode, and finally the prediction modes to use
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for each of the sub-blocks. For a very large image, 512k
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only leaves room to few bits per 16x16 macroblock. The
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absolute minimum is 4 bits per macroblock. Skip, segment,
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and mode information can use up almost all these 4 bits
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(although the case is unlikely), which is problematic for
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very large images. The partition_limit factor controls how
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frequently the most bit-costly mode (intra 4x4) will be
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used. This is useful in case the 512k limit is reached and
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the following message is displayed: <i>Error code: 6
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(PARTITION0_OVERFLOW: Partition #0 is too big to fit
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512k)</i>. If using <b>-partition_limit</b> is not enough to
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meet the 512k constraint, one should use less segments in
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order to save more header bits per macroblock. See the
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<b>-segments</b> option.</p>
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<p style="margin-left:11%;"><b>−size</b>
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<i>int</i></p>
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<p style="margin-left:22%;">Specify a target size (in
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bytes) to try and reach for the compressed output.
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Compressor will make several pass of partial encoding in
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order to get as close as possible to this target.</p>
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<p style="margin-left:11%;"><b>−psnr</b>
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<i>float</i></p>
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<p style="margin-left:22%;">Specify a target PSNR (in dB)
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to try and reach for the compressed output. Compressor will
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make several pass of partial encoding in order to get as
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close as possible to this target.</p>
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<p style="margin-left:11%;"><b>−pass</b>
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<i>int</i></p>
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<p style="margin-left:22%;">Set a maximum number of passes
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to use during the dichotomy used by options
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<b>−size</b> or <b>−psnr</b>. Maximum value is
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10.</p>
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<p style="margin-left:11%;"><b>−resize</b> <i>width
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height</i></p>
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<p style="margin-left:22%;">Resize the source to a
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rectangle with size <b>width</b> x <b>height</b>. If either
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(but not both) of the <b>width</b> or <b>height</b>
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parameters is 0, the value will be calculated preserving the
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aspect-ratio.</p>
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<p style="margin-left:11%;"><b>−crop</b>
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<i>x_position y_position width height</i></p>
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<p style="margin-left:22%;">Crop the source to a rectangle
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with top-left corner at coordinates (<b>x_position</b>,
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<b>y_position</b>) and size <b>width</b> x <b>height</b>.
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This cropping area must be fully contained within the source
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rectangle.</p>
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<p style="margin-left:11%;"><b>−s</b> <i>width
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height</i></p>
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<p style="margin-left:22%;">Specify that the input file
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actually consists of raw Y’CbCr samples following the
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ITU-R BT.601 recommendation, in 4:2:0 linear format. The
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luma plane has size <b>width</b> x <b>height</b>.</p>
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<p style="margin-left:11%;"><b>−map</b>
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<i>int</i></p>
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<p style="margin-left:22%;">Output additional ASCII-map of
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encoding information. Possible map values range from 1 to 6.
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This is only meant to help debugging.</p>
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<p style="margin-left:11%;"><b>−pre</b>
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<i>int</i></p>
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<p style="margin-left:22%;">Specify some pre-processing
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steps. Using a value of ’2’ will trigger
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quality-dependent pseudo-random dithering during
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RGBA->YUVA conversion (lossy compression only).</p>
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<p style="margin-left:11%;"><b>−alpha_filter</b>
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<i>string</i></p>
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<p style="margin-left:22%;">Specify the predictive
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filtering method for the alpha plane. One of
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’none’, ’fast’ or
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’best’, in increasing complexity and slowness
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order. Default is ’fast’. Internally, alpha
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filtering is performed using four possible predictions
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(none, horizontal, vertical, gradient). The
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’best’ mode will try each mode in turn and pick
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the one which gives the smaller size. The ’fast’
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mode will just try to form an a-priori guess without testing
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all modes.</p>
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<p style="margin-left:11%;"><b>−alpha_method</b>
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<i>int</i></p>
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<p style="margin-left:22%;">Specify the algorithm used for
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alpha compression: 0 or 1. Algorithm 0 denotes no
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compression, 1 uses WebP lossless format for compression.
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The default is 1.</p>
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<p style="margin-left:11%;"><b>−alpha_cleanup</b></p>
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<p style="margin-left:22%;">Modify unseen RGB values under
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fully transparent area, to help compressibility. The default
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is off.</p>
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<p style="margin-left:11%;"><b>−blend_alpha</b>
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<i>int</i></p>
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<p style="margin-left:22%;">This option blends the alpha
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channel (if present) with the source using the background
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color specified in hexadecimal as 0xrrggbb. The alpha
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channel is afterward reset to the opaque value 255.</p>
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<p style="margin-left:11%;"><b>−noalpha</b></p>
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<p style="margin-left:22%;">Using this option will discard
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the alpha channel.</p>
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<p style="margin-left:11%;"><b>−lossless</b></p>
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<p style="margin-left:22%;">Encode the image without any
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loss.</p>
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<p style="margin-left:11%;"><b>−hint</b>
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<i>string</i></p>
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<p style="margin-left:22%;">Specify the hint about input
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image type. Possible values are: <b>photo</b>,
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<b>picture</b> or <b>graph</b>.</p>
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<p style="margin-left:11%;"><b>−metadata</b>
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<i>string</i></p>
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<p style="margin-left:22%;">A comma separated list of
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metadata to copy from the input to the output if present.
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Valid values: <b>all</b>, <b>none</b>, <b>exif</b>,
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<b>icc</b>, <b>xmp</b>. The default is <b>none</b>.</p>
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<p style="margin-left:22%; margin-top: 1em">Note: each
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input format may not support all combinations.</p>
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<table width="100%" border=0 rules="none" frame="void"
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cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="11%"></td>
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<td width="9%">
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<p style="margin-top: 1em" valign="top"><b>−noasm</b></p> </td>
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<td width="2%"></td>
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<td width="78%">
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<p style="margin-top: 1em" valign="top">Disable all
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assembly optimizations.</p></td>
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<tr valign="top" align="left">
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<td width="11%"></td>
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<td width="9%">
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<p style="margin-top: 1em" valign="top"><b>−v</b></p> </td>
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<td width="2%"></td>
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<td width="78%">
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<p style="margin-top: 1em" valign="top">Print extra
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information (encoding time in particular).</p></td>
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</table>
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<p style="margin-left:11%;"><b>−print_psnr</b></p>
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<p style="margin-left:22%;">Compute and report average PSNR
|
|
(Peak-Signal-To-Noise ratio).</p>
|
|
|
|
<p style="margin-left:11%;"><b>−print_ssim</b></p>
|
|
|
|
<p style="margin-left:22%;">Compute and report average SSIM
|
|
(structural similarity metric, see
|
|
http://en.wikipedia.org/wiki/SSIM for additional
|
|
details).</p>
|
|
|
|
<p style="margin-left:11%;"><b>−print_lsim</b></p>
|
|
|
|
<p style="margin-left:22%;">Compute and report local
|
|
similarity metric (sum of lowest error amongst the
|
|
collocated pixel neighbors).</p>
|
|
|
|
<p style="margin-left:11%;"><b>−progress</b></p>
|
|
|
|
<p style="margin-left:22%;">Report encoding progress in
|
|
percent.</p>
|
|
|
|
<table width="100%" border=0 rules="none" frame="void"
|
|
cellspacing="0" cellpadding="0">
|
|
<tr valign="top" align="left">
|
|
<td width="11%"></td>
|
|
<td width="9%">
|
|
|
|
|
|
|
|
<p style="margin-top: 1em" valign="top"><b>−quiet</b></p> </td>
|
|
<td width="2%"></td>
|
|
<td width="78%">
|
|
|
|
|
|
<p style="margin-top: 1em" valign="top">Do not print
|
|
anything.</p> </td>
|
|
<tr valign="top" align="left">
|
|
<td width="11%"></td>
|
|
<td width="9%">
|
|
|
|
|
|
|
|
<p style="margin-top: 1em" valign="top"><b>−short</b></p> </td>
|
|
<td width="2%"></td>
|
|
<td width="78%">
|
|
|
|
|
|
<p style="margin-top: 1em" valign="top">Only print brief
|
|
information (output file size and PSNR) for testing
|
|
purpose.</p> </td>
|
|
</table>
|
|
|
|
<a name="BUGS"></a>
|
|
<h2>BUGS</h2>
|
|
|
|
|
|
<p style="margin-left:11%; margin-top: 1em">Please report
|
|
all bugs to our issue tracker:
|
|
http://code.google.com/p/webp/issues <br>
|
|
Patches welcome! See this page to get started:
|
|
http://www.webmproject.org/code/contribute/submitting-patches/</p>
|
|
|
|
<a name="EXAMPLES"></a>
|
|
<h2>EXAMPLES</h2>
|
|
|
|
|
|
<p style="margin-left:11%; margin-top: 1em">cwebp −q
|
|
50 -lossless picture.png −o picture_lossless.webp <br>
|
|
cwebp −q 70 picture_with_alpha.png −o
|
|
picture_with_alpha.webp <br>
|
|
cwebp −sns 70 −f 50 −size 60000
|
|
picture.png −o picture.webp <br>
|
|
cwebp −o picture.webp −−
|
|
−−−picture.png</p>
|
|
|
|
<a name="AUTHORS"></a>
|
|
<h2>AUTHORS</h2>
|
|
|
|
|
|
<p style="margin-left:11%; margin-top: 1em"><b>cwebp</b>
|
|
was written by the WebP team. <br>
|
|
The latest source tree is available at
|
|
http://www.webmproject.org/code</p>
|
|
|
|
<p style="margin-left:11%; margin-top: 1em">This manual
|
|
page was written by Pascal Massimino
|
|
<pascal.massimino@gmail.com>, for the Debian project
|
|
(and may be used by others).</p>
|
|
|
|
<a name="SEE ALSO"></a>
|
|
<h2>SEE ALSO</h2>
|
|
|
|
|
|
|
|
<p style="margin-left:11%; margin-top: 1em"><b>dwebp</b>(1),
|
|
<b>gif2webp</b>(1) <br>
|
|
Please refer to http://developers.google.com/speed/webp/ for
|
|
additional information.</p>
|
|
<hr>
|
|
</body>
|
|
</html>
|