Provided by: webp_1.2.4-0.3_amd64 bug

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.  Note: Animated WebP files
       are not supported.

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:
       https://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).

SEE ALSO

       cwebp(1), gif2webp(1), webpmux(1)
       Please refer to https://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

                                        November 17, 2021                                DWEBP(1)