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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.  Note: Ani-
     mated 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).  Us-
	    ing "-" as output name will direct output to 'stdout'.

     -- string
	    Explicitly	specify the input file. This option is useful if the in-
	    put 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 debug-
	    ging 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 quan-
	    tized during compression, this flag will allow dithering the  recon-
	    structed 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 co-
	    ordinates (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 im-
	    ages, 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 cal-
	    culated preserving the aspect-ratio.

     -quiet
	    Do not print anything.

     -v     Print extra information (decoding time in particular).

     -noasm
	    Disable all assembly optimizations.

EXIT STATUS
     If there were no problems during execution, dwebp exits with the  value  of
     the C constant EXIT_SUCCESS. This is usually zero.

     If an error occurs, dwebp exits with the value of the C constant EXIT_FAIL-
     URE. This is usually one.

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.google-
     source.com/webm/libwebp

     This  manual  page   was	written   by   Pascal	Massimino   <pascal.mas-
     simino@gmail.com>, for the Debian project (and may be used by others).

REPORTING BUGS
     Please report all bugs to the issue tracker: https://issues.webmproject.org
     Patches  welcome!	See  this  page  to  get  started:  https://www.webmpro-
     ject.org/code/contribute/submitting-patches/

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

				  July 18, 2024 			DWEBP(1)

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