Tribblix: manual page: gif2webp.1

GIF2WEBP(1) User Commands GIF2WEBP(1)

NAME

gif2webp - Convert a GIF image to WebP

SYNOPSIS

gif2webp [options] input_file.gif -o output_file.webp

DESCRIPTION

This manual page documents the gif2webp command.

gif2webp converts a GIF image to a WebP image.

OPTIONS

The basic options are:

-o string
Specify the name of the output WebP file. If omitted, gif2webp
will perform conversion but only report statistics. Using "-"
as output name will direct output to 'stdout'.

-- string
Explicitly specify the input file. This option is useful if
the input file starts with an '-' for instance. This option
must appear last. Any other options afterward will be
ignored. If the input file is "-", the data will be read from
stdin instead of a file.

-h, -help
Usage information.

-version
Print the version number (as major.minor.revision) and exit.

-lossy Encode the image using lossy compression.

-mixed Mixed compression mode: optimize compression of the image by
picking either lossy or lossless compression for each frame
heuristically.

-q float
Specify the compression factor for RGB channels between 0 and
100. The default is 75.
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.
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.

-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.

-min_size
Encode image to achieve smallest size. This disables key frame
insertion and picks the dispose method resulting in the
smallest output for each frame. It uses lossless compression
by default, but can be combined with -q, -m, -lossy or -mixed
options.

-kmin int

-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.
A 'kmax' value of 0 will turn off insertion of key frames. A
'kmax' value of 1 will result in all frames being key frames.
'kmin' value is not taken into account in both these special
cases. 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.
These two options are relevant only for animated images with
large number of frames (>50).
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.
Some restrictions:
(i) kmin < kmax,
(ii) kmin >= kmax / 2 + 1 and
(iii) kmax - kmin <= 30.
If any of these restrictions are not met, they will be
enforced automatically.

-metadata string
A comma separated list of metadata to copy from the input to
the output if present. Valid values: all, none, icc, xmp.
The default is xmp.

-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.

-mt Use multi-threading for encoding, if possible.

-loop_compatibility
If enabled, handle the loop information in a compatible
fashion for Chrome version prior to M62 (inclusive) and
Firefox.

-v Print extra information.

-quiet Do not print anything.

BUGS

Please report all bugs to the issue tracker:
https://bugs.chromium.org/p/webp
Patches welcome! See this page to get started:
https://www.webmproject.org/code/contribute/submitting-patches/

EXAMPLES

gif2webp picture.gif -o picture.webp
gif2webp -q 70 picture.gif -o picture.webp
gif2webp -lossy -m 3 picture.gif -o picture_lossy.webp
gif2webp -lossy -f 50 picture.gif -o picture.webp
gif2webp -q 70 -o picture.webp -- ---picture.gif
cat picture.gif | gif2webp -o - -- - > output.webp

AUTHORS

gif2webp is a part of libwebp and was written by the WebP team.
The latest source tree is available at
https://chromium.googlesource.com/webm/libwebp

This manual page was written by Urvang Joshi <urvang@google.com>, for
the Debian project (and may be used by others).