dwebp - decompress a WebP file to an image file
dwebp [options] input_file.webp
DWEBP(1) General Commands Manual DWEBP(1)
NAME
dwebp - decompress a WebP file to an image file
SYNOPSIS
dwebp [options] input_file.webp
DESCRIPTION
This manual page documents the dwebp command.
dwebp decompresses WebP files into PNG, PAM, PPM or PGM images.
OPTIONS
The basic options are:
-h Print usage summary.
-version
Print the version number (as major.minor.revision) and exit.
-o string
Specify the name of the output file (as PNG format by default).
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.
-bmp Change the output format to uncompressed BMP.
-tiff Change the output format to uncompressed TIFF.
-pam Change the output format to PAM (retains alpha).
-ppm Change the output format to PPM (discards alpha).
-pgm Change the output format to PGM. The output consists of
luma/chroma samples instead of RGB, using the IMC4 layout. This
option is mainly for verification and debugging purposes.
-yuv Change the output format to raw YUV. The output consists of
luma/chroma-U/chroma-V samples instead of RGB, saved sequen-
tially as individual planes. This option is mainly for verifica-
tion and debugging purposes.
-nofancy
Don't use the fancy upscaler for YUV420. This may lead to jaggy
edges (especially the red ones), but should be faster.
-nofilter
Don't use the in-loop filtering process even if it is required
by the bitstream. This may produce visible blocks on the non-
compliant output, but it will make the decoding faster.
-dither strength
Specify a dithering strength between 0 and 100. Dithering is a
post-processing effect applied to chroma components in lossy
compression. It helps by smoothing gradients and avoiding band-
ing artifacts.
-alpha_dither
If the compressed file contains a transparency plane that was
quantized during compression, this flag will allow dithering the
reconstructed plane in order to generate smoother transparency
gradients.
-nodither
Disable all dithering (default).
-mt Use multi-threading for decoding, if possible.
-crop x_position y_position width height
Crop the decoded picture to a rectangle with top-left corner at
coordinates (x_position, y_position) and size width x height.
This cropping area must be fully contained within the source
rectangle. The top-left corner will be snapped to even coordi-
nates if needed. This option is meant to reduce the memory
needed for cropping large images. Note: the cropping is applied
before any scaling.
-flip Flip decoded image vertically (can be useful for OpenGL textures
for instance).
-resize, -scale width height
Rescale the decoded picture to dimension width x height. This
option is mostly intended to reducing the memory needed to
decode large images, when only a small version is needed (thumb-
nail, preview, etc.). Note: scaling is applied after cropping.
If either (but not both) of the width or height parameters is 0,
the value will be calculated preserving the aspect-ratio.
-quiet Do not print anything.
-v Print extra information (decoding time in particular).
-noasm Disable all assembly optimizations.
BUGS
Please report all bugs to the issue tracker:
https://bugs.chromium.org/p/webp
Patches welcome! See this page to get started: http://www.webmpro-
ject.org/code/contribute/submitting-patches/
EXAMPLES
dwebp picture.webp -o output.png
dwebp picture.webp -ppm -o output.ppm
dwebp -o output.ppm -- ---picture.webp
cat picture.webp | dwebp -o - -- - > output.ppm
AUTHORS
dwebp is a part of libwebp and was written by the WebP team.
The latest source tree is available at https://chromium.google-
source.com/webm/libwebp
This manual page was written by Pascal Massimino <pascal.mas-
simino@gmail.com>, for the Debian project (and may be used by others).
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+-----------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------------+
|Availability | image/library/libwebp |
+---------------+-----------------------+
|Stability | Pass-through volatile |
+---------------+-----------------------+
SEE ALSO
cwebp(1), gif2webp(1), webpmux(1)
Please refer to http://developers.google.com/speed/webp/ for additional
information.
Output file format details
PAM: http://netpbm.sourceforge.net/doc/pam.html
PGM: http://netpbm.sourceforge.net/doc/pgm.html
PPM: http://netpbm.sourceforge.net/doc/ppm.html
PNG: http://www.libpng.org/pub/png/png-sitemap.html#info
NOTES
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from http://downloads.webmpro-
ject.org/releases/webp/libwebp-1.0.0-rc3.tar.gz
Further information about this software can be found on the open source
community website at https://www.webmproject.org/.
June 23, 2016 DWEBP(1)