@nwrks/webp-converter/bin/libwebp_osx_arm/doc/dwebp.txt

A small node.js library for converting any image to webp file format or converting webp image to any image file format.

DWEBP(1)                    General Commands Manual                   DWEBP(1)



1mNAME0m
       dwebp - decompress a WebP file to an image file

1mSYNOPSIS0m
       1mdwebp 22m[4moptions24m] 4minput_file.webp0m

1mDESCRIPTION0m
       This manual page documents the 1mdwebp 22mcommand.

       1mdwebp  22mdecompresses WebP files into PNG, PAM, PPM or PGM images.  Note:
       Animated WebP files are not supported.

1mOPTIONS0m
       The basic options are:

       1m-h     22mPrint usage summary.

       1m-version0m
              Print the version number (as major.minor.revision) and exit.

       1m-o 4m22mstring0m
              Specify the name of the output file (as PNG format by  default).
              Using "-" as output name will direct output to 'stdout'.

       1m-- 4m22mstring0m
              Explicitly  specify the input file. This option is useful if the
              input file starts with an '-' for instance. This option must ap-
              pear  1mlast22m.  Any other options afterward will be ignored. If the
              input file is "-", the data will be read from 4mstdin24m instead of a
              file.

       1m-bmp   22mChange the output format to uncompressed BMP.

       1m-tiff  22mChange the output format to uncompressed TIFF.

       1m-pam   22mChange the output format to PAM (retains alpha).

       1m-ppm   22mChange the output format to PPM (discards alpha).

       1m-pgm   22mChange  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.

       1m-yuv   22mChange  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.

       1m-nofancy0m
              Don't use the fancy upscaler for YUV420. This may lead to  jaggy
              edges (especially the red ones), but should be faster.

       1m-nofilter0m
              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.

       1m-dither 4m22mstrength0m
              Specify  a  dithering 1mstrength 22mbetween 0 and 100. Dithering is a
              post-processing effect applied to  chroma  components  in  lossy
              compression.  It helps by smoothing gradients and avoiding band-
              ing artifacts.

       1m-alpha_dither0m
              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.

       1m-nodither0m
              Disable all dithering (default).

       1m-mt    22mUse multi-threading for decoding, if possible.

       1m-crop 4m22mx_position24m 4my_position24m 4mwidth24m 4mheight0m
              Crop  the decoded picture to a rectangle with top-left corner at
              coordinates (1mx_position22m, 1my_position22m) and size  1mwidth  22mx  1mheight22m.
              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
              4mbefore24m any scaling.

       1m-flip  22mFlip decoded image vertically (can be useful for OpenGL textures
              for instance).

       1m-resize22m, 1m-scale 4m22mwidth24m 4mheight0m
              Rescale the decoded picture to dimension 1mwidth  22mx  1mheight22m.  This
              option  is  mostly intended to reducing the memory needed to de-
              code large images, when only a small version is  needed  (thumb-
              nail,  preview,  etc.). Note: scaling is applied 4mafter24m cropping.
              If either (but not both) of the 1mwidth 22mor 1mheight 22mparameters is 0,
              the value will be calculated preserving the aspect-ratio.

       1m-quiet 22mDo not print anything.

       1m-v     22mPrint extra information (decoding time in particular).

       1m-noasm 22mDisable all assembly optimizations.


1mBUGS0m
       Please     report     all     bugs     to     the     issue    tracker:
       https://bugs.chromium.org/p/webp
       Patches welcome! See this page  to  get  started:  https://www.webmpro-
       ject.org/code/contribute/submitting-patches/


1mEXAMPLES0m
       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


1mAUTHORS0m
       1mdwebp 22mis 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).


1mSEE ALSO0m
       1mcwebp22m(1), 1mgif2webp22m(1), 1mwebpmux22m(1)
       Please  refer  to  https://developers.google.com/speed/webp/  for addi-
       tional information.

   1mOutput file format details0m
       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



                               November 17, 2021                      DWEBP(1)