Ubuntu Manpage: dwebp - decompress a WebP file to an image file

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: Animated 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). 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:
       https://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).