huschi.net

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).
       -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 ICM4 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 will make the decoding faster.
       -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.
       -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.
       -v     Print extra information (decoding time in particular).
       -noasm Disable all assembly optimizations.

BUGS
       Please    report     all     bugs     to     our     issue     tracker:
       http://code.google.com/p/webp/issues
       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

AUTHORS
       dwebp was written by the WebP team.
       The latest source tree is available at http://www.webmproject.org/code
       This  manual  page  was  written  by  Pascal   Massimino   <pascal.mas-
       simino AT gmail.com>, for the Debian project (and may be used by others).

SEE ALSO
       cwebp(1), webpmux(1), gif2webp(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

                               February 01, 2013                      DWEBP(1)