DWEBP(1)                                                              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).
              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/chromaU/chromaV  samples  instead  of  RGB, saved sequen
              tially as individual planes. This option is mainly for verifica
              tion and debugging purposes.

      nofancy
              Dont  use the fancy upscaler for YUV420. This may lead to jaggy
              edges (especially the red ones), but should be faster.

      nofilter
              Dont use the inloop 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
              postprocessing  effect  applied  to  chroma components in lossy
              compression.  It helps by smoothing gradients and avoiding band
              ing artifacts.

      nodither
              Disable all dithering (default).

      mt    Use multithreading for decoding, if possible.

      crop x_position y_position width height
              Crop  the decoded picture to a rectangle with topleft corner at
              coordinates (x_position, y_position) and size  width  x  height.
              This  cropping  area  must  be fully contained within the source
              rectangle.  The topleft 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/submittingpatches/


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 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@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/pngsitemap.html#info



                                 July 22, 2014                        DWEBP(1)