Ubuntu Manpage: dwebp - decompress a WebP file to an image file

Provided by: webp_0.6.1-2ubuntu0.20.04.3_amd64

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 sequentially as individual planes. This option is
mainly for verification 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 banding 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
coordinates 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 (thumbnail, 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.webmproject.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.googlesource.com/webm/libwebp

       This  manual  page  was  written by Pascal Massimino <pascal.massimino@gmail.com>, for the
       Debian project (and may be used by others).