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134 lines
4.6 KiB
Groff
134 lines
4.6 KiB
Groff
.\" Hey, EMACS: -*- nroff -*-
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.TH IMG2WEBP 1 "November 26, 2024"
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.SH NAME
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img2webp \- create animated WebP file from a sequence of input images.
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.SH SYNOPSIS
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.B img2webp
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[file_options] [[frame_options] frame_file]... [\-o webp_file]
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.br
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.B img2webp argument_file_name
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.br
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.SH DESCRIPTION
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This manual page documents the
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.B img2webp
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command.
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.PP
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\fBimg2webp\fP compresses a sequence of images using the animated WebP format.
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Input images can either be PNG, JPEG, TIFF or WebP.
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If a single file name (not starting with the character '\-') is supplied as
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the argument, the command line arguments are actually tokenized from this file.
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This allows for easy scripting or using a large number of arguments.
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.SH FILE-LEVEL OPTIONS
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The file-level options are applied at the beginning of the compression process,
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before the input frames are read.
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.TP
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.BI \-o " string
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Specify the name of the output WebP file.
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.TP
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.BI \-min_size
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Encode images to achieve smallest size. This disables key frame insertion and
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picks the parameters resulting in the smallest output for each frame. It uses
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lossless compression by default, but can be combined with \-q, \-m, \-lossy or
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\-mixed options.
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.TP
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.BI \-kmin " int
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.TP
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.BI \-kmax " int
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Specify the minimum and maximum distance between consecutive key frames
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(independently decodable frames) in the output animation. The tool will insert
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some key frames into the output animation as needed so that this criteria is
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satisfied.
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.br
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.B \-mixed
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Mixed compression mode: optimize compression of the image by picking either
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lossy or lossless compression for each frame heuristically. This global
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option disables the local option \fB-lossy\fP and \fB-lossless\fP .
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.TP
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.BI \-near_lossless " int
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Specify the level of near\-lossless image preprocessing. This option adjusts
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pixel values to help compressibility, but has minimal impact on the visual
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quality. It triggers lossless compression mode automatically. The range is 0
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(maximum preprocessing) to 100 (no preprocessing, the default). The typical
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value is around 60. Note that lossy with \fB\-q 100\fP can at times yield
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better results.
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.TP
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.B \-sharp_yuv
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Use more accurate and sharper RGB->YUV conversion. Note that this process is
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slower than the default 'fast' RGB->YUV conversion.
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.TP
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.BI \-loop " int
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Specifies the number of times the animation should loop. Using '0'
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means 'loop indefinitely'.
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.TP
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.BI \-v
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Be more verbose.
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.TP
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.B \-h, \-help
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A short usage summary.
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.TP
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.B \-version
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Print the version numbers of the relevant libraries used.
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.SH PER-FRAME OPTIONS
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The per-frame options are applied for the images following as arguments in the
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command line. They can be modified any number of times preceding each particular
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input image.
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.TP
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.BI \-d " int
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Specify the image duration in milliseconds.
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.TP
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.B \-lossless, \-lossy
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Compress the next image(s) using lossless or lossy compression mode. The
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default mode is lossless.
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.TP
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.BI \-q " float
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Specify the compression factor between 0 and 100. The default is 75.
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.TP
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.BI \-m " int
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Specify the compression method to use. This parameter controls the
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trade off between encoding speed and the compressed file size and quality.
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Possible values range from 0 to 6. Default value is 4.
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When higher values are used, the encoder will spend more time inspecting
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additional encoding possibilities and decide on the quality gain.
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Lower value can result in faster processing time at the expense of
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larger file size and lower compression quality.
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.TP
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.B \-exact, \-noexact
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Preserve or alter RGB values in transparent area. The default is
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\fB-noexact\fP, to help compressibility. Note \fB\-noexact\fP may cause
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artifacts in frames compressed with \fB\-lossy\fP.
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.SH EXIT STATUS
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If there were no problems during execution, \fBimg2webp\fP exits with the value
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of the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
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.PP
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If an error occurs, \fBimg2webp\fP exits with the value of the C constant
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\fBEXIT_FAILURE\fP. This is usually one.
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.SH EXAMPLE
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img2webp -loop 2 in0.png -lossy in1.jpg -d 80 in2.tiff -o out.webp
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.br
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.SH AUTHORS
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\fBimg2webp\fP is a part of libwebp and was written by the WebP team.
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.br
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The latest source tree is available at
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https://chromium.googlesource.com/webm/libwebp
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.PP
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This manual page was written by Pascal Massimino <pascal.massimino@gmail.com>,
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for the Debian project (and may be used by others).
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.SH REPORTING BUGS
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Please report all bugs to the issue tracker:
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https://issues.webmproject.org
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.br
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Patches welcome! See this page to get started:
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https://www.webmproject.org/code/contribute/submitting\-patches/
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.SH SEE ALSO
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.BR webpmux (1),
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.BR gif2webp (1)
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.br
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Please refer to https://developers.google.com/speed/webp/ for additional
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information.
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