6f36ade926
from man-pages (7): provides a comma-separated list of related man pages, ordered by section number and then alphabetically by name, possibly followed by other related pages or documents. Do not terminate this with a period. Change-Id: I6763b3b3a89f3c2e9ed5c1a4e9d05fb9ce85dd40
144 lines
4.5 KiB
Groff
144 lines
4.5 KiB
Groff
.\" Hey, EMACS: -*- nroff -*-
|
|
.TH GIF2WEBP 1 "December 17, 2013"
|
|
.SH NAME
|
|
gif2webp \- Convert a GIF image to WebP
|
|
.SH SYNOPSIS
|
|
.B gif2webp
|
|
.RI [ options ] " input_file.gif \-o output_file.webp
|
|
.br
|
|
.SH DESCRIPTION
|
|
This manual page documents the
|
|
.B gif2webp
|
|
command.
|
|
.PP
|
|
\fBgif2webp\fP converts a GIF image to a WebP image.
|
|
.SH OPTIONS
|
|
The basic options are:
|
|
.TP
|
|
.BI \-o " string
|
|
Specify the name of the output WebP file. If omitted, \fBgif2webp\fP will
|
|
perform conversion but only report statistics.
|
|
.TP
|
|
.B \-h, \-help
|
|
Usage information.
|
|
.TP
|
|
.B \-version
|
|
Print the version number (as major.minor.revision) and exit.
|
|
.TP
|
|
.B \-lossy
|
|
Encode the image using lossy compression.
|
|
.TP
|
|
.B \-mixed
|
|
Mixed compression mode: optimize compression of the image by picking either
|
|
lossy or lossless compression for each frame heuristically.
|
|
.TP
|
|
.BI \-q " float
|
|
Specify the compression factor for RGB channels between 0 and 100. The default
|
|
is 75.
|
|
.br
|
|
In case of lossless compression (default), a small factor enables faster
|
|
compression speed, but produces a larger file. Maximum compression is achieved
|
|
by using a value of 100.
|
|
.br
|
|
In case of lossy compression (specified by the \-lossy option), a small factor
|
|
produces a smaller file with lower quality. Best quality is achieved by using a
|
|
value of 100.
|
|
.TP
|
|
.BI \-m " int
|
|
Specify the compression method to use. This parameter controls the
|
|
trade off between encoding speed and the compressed file size and quality.
|
|
Possible values range from 0 to 6. Default value is 4.
|
|
When higher values are used, the encoder will spend more time inspecting
|
|
additional encoding possibilities and decide on the quality gain.
|
|
Lower value can result is faster processing time at the expense of
|
|
larger file size and lower compression quality.
|
|
.TP
|
|
.BI \-kmin " int
|
|
.TP
|
|
.BI \-kmax " int
|
|
Specify the minimum and maximum distance between consecutive key frames
|
|
(independently decodable frames) in the output animation. The tool will insert
|
|
some key frames into the output animation as needed so that this criteria is
|
|
satisfied.
|
|
.br
|
|
A 'kmin' value of 0 will turn off insertion of key frames.
|
|
Typical values are in the range 3 to 30. Default values are kmin = 9,
|
|
kmax = 17 for lossless compression and kmin = 3, kmax = 5 for lossy compression.
|
|
.br
|
|
These two options are relevant only for animated images with large number of
|
|
frames (>50).
|
|
.br
|
|
When lower values are used, more frames will be converted to key frames. This
|
|
may lead to smaller number of frames required to decode a frame on average,
|
|
thereby improving the decoding performance. But this may lead to slightly bigger
|
|
file sizes.
|
|
Higher values may lead to worse decoding performance, but smaller file sizes.
|
|
.br
|
|
Some restrictions:
|
|
.br
|
|
(i) kmin < kmax,
|
|
.br
|
|
(ii) kmin >= kmax / 2 + 1 and
|
|
.br
|
|
(iii) kmax - kmin <= 30.
|
|
.br
|
|
If any of these restrictions are not met, they will be enforced automatically.
|
|
.TP
|
|
.BI \-metadata " string
|
|
A comma separated list of metadata to copy from the input to the output if
|
|
present.
|
|
Valid values: \fBall\fP, \fBnone\fP, \fBicc\fP, \fBxmp\fP.
|
|
The default is \fBxmp\fP.
|
|
.TP
|
|
.BI \-f " int
|
|
For lossy encoding only (specified by the \-lossy option). Specify the strength
|
|
of the deblocking filter, between 0 (no filtering) and 100 (maximum filtering).
|
|
A value of 0 will turn off any filtering. Higher value will increase the
|
|
strength of the filtering process applied after decoding the picture. The higher
|
|
the value the smoother the picture will appear. Typical values are usually in
|
|
the range of 20 to 50.
|
|
.TP
|
|
.B \-mt
|
|
Use multi-threading for encoding, if possible. This option is only effective
|
|
when using lossy compression.
|
|
.TP
|
|
.B \-v
|
|
Print extra information.
|
|
.TP
|
|
.B \-quiet
|
|
Do not print anything.
|
|
|
|
.SH BUGS
|
|
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/
|
|
|
|
.SH EXAMPLES
|
|
gif2webp picture.gif \-o picture.webp
|
|
.br
|
|
gif2webp \-q 70 picture.gif \-o picture.webp
|
|
.br
|
|
gif2webp \-lossy \-m 3 picture.gif \-o picture_lossy.webp
|
|
.br
|
|
gif2webp \-lossy \-f 50 picture.gif \-o picture.webp
|
|
.br
|
|
gif2webp \-q 70 \-o picture.webp \-\- \-\-\-picture.gif
|
|
|
|
.SH AUTHORS
|
|
\fBgif2webp\fP was written by the WebP team.
|
|
.br
|
|
The latest source tree is available at http://www.webmproject.org/code
|
|
.PP
|
|
This manual page was written by Urvang Joshi <urvang@google.com>, for the
|
|
Debian project (and may be used by others).
|
|
|
|
.SH SEE ALSO
|
|
.BR cwebp (1),
|
|
.BR dwebp (1),
|
|
.BR webpmux (1)
|
|
.br
|
|
Please refer to http://developers.google.com/speed/webp/ for additional
|
|
information.
|