dwebp decompresses WebP files into PNG, PAM, PPM or PGM images. Note: Animated WebP files are not supported.
-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.
If an error occurs, dwebp exits with the value of the C constant EXIT_FAILURE. This is usually one.
dwebp picture.webp -ppm -o output.ppm
dwebp -o output.ppm -- ---picture.webp
cat picture.webp | dwebp -o - -- - > output.ppm
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).
Patches welcome! See this page to get started: https://www.webmproject.org/code/contribute/submitting-patches/
Please refer to https://developers.google.com/speed/webp/ for additional information.
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