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

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).

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

                                                  June 23, 2016                                         DWEBP(1)