Provided by: webp_0.6.1-2_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)