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gif2webp(1) [centos man page]

GIF2WEBP(1)						      General Commands Manual						       GIF2WEBP(1)

gif2webp - Convert a GIF image to WebP SYNOPSIS
gif2webp [options] input_file.gif -o output_file.webp DESCRIPTION
This manual page documents the gif2webp command. gif2webp converts a GIF image to a WebP image. OPTIONS
The basic options are: -o string Specify the name of the output WebP file. If omitted, gif2webp will perform conversion but only report statistics. -h, -help Usage information. -version Print the version number (as major.minor.revision) and exit. -lossy Encode the image using lossy compression. -q float Specify the compression factor for RGB channels between 0 and 100. The default is 75. In case of lossless compression (default), a small factor enables faster compression speed, but produces a larger file. Maximum com- pression is achieved by using a value of 100. In case of lossy compression (specified by the -lossy option), a small factor produces a smaller file with lower quality. Best qual- ity is achieved by using a value of 100. -m int Specify the compression method to use. This parameter controls the trade off between encoding speed and the compressed file size and quality. Possible values range from 0 to 6. Default value is 4. When higher values are used, the encoder will spend more time inspecting additional encoding possibilities and decide on the quality gain. Lower value can result is faster processing time at the expense of larger file size and lower compression quality. -f int For lossy encoding only (specified by the -lossy option). Specify the strength of the deblocking filter, between 0 (no filtering) and 100 (maximum filtering). A value of 0 will turn off any filtering. Higher value will increase the strength of the filtering process applied after decoding the picture. The higher the value the smoother the picture will appear. Typical values are usually in the range of 20 to 50. -v Print extra information. -quiet Do not print anything. BUGS
Please report all bugs to our issue tracker: Patches welcome! See this page to get started: EXAMPLES
gif2webp picture.gif -o picture.webp gif2webp -q 70 picture.gif -o picture.webp gif2webp -lossy -m 3 picture.gif -o picture_lossy.webp gif2webp -lossy -f 50 picture.gif -o picture.webp AUTHORS
gif2webp was written by the WebP team. The latest source tree is available at This manual page was written by Urvang Joshi <>, for the Debian project (and may be used by others). SEE ALSO
dwebp(1), cwebp(1), webpmux(1). Please refer to for additional information. February 01, 2013 GIF2WEBP(1)

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CJB2(1) 							   DjVuLibre-3.5							   CJB2(1)

cjb2 - Simple DjVuBitonal encoder. SYNOPSIS
cjb2 [options] inputfile outputdjvufile DESCRIPTION
This is a simple encoder for bitonal files. Argument inputfile is the name of a PBM or bitonal TIFF file containing a single document image. This program produces a DjVuBitonal file named outputdjvufile. The default compression process is lossless: decoding the DjVuBitonal file at full resolution will produce an image exactly identical to the input file. Lossy compression is enabled by options -losslevel, -lossy, or -clean. OPTIONS
-dpi n Specify the resolution information encoded into the output file expressed in dots per inch. The resolution information encoded in DjVu files determine how the decoder scales the image on a particular display. Meaningful resolutions range from 25 to 1200. The default resolution for TIFF files is the resolution is the resolution specified by the input file. The default resolution for PBM files is 300 dpi. -lossless Ensure that the encoded image is pixel-per-pixel equal to the initial image. This option is is equivalent to -losslevel 0 and is the default. -clean Only remove flyspecks from the input image. This option enables a heuristic algorithm that removes very small marks. Such marks are often causes by noise and dust during the scanning process. The threshold mark size is chosen according to the resolution spec- ified with option This option is is equivalent to -losslevel 1. -lossy Substitute patterns with small variations. In addition to the flyspeck removal heuristic, this option enables an algorithm that encodes certain characters by simply replicating the shape of a previously encoded character with a similar shape. This option is is equivalent to -losslevel 100. -losslevel x Specify the aggressiveness of the lossy compression. Its argument ranges from 0 to 200. Higher values generate smaller files with more potential distortions. Loss level 0 corresponds to lossless encoding. Loss level 1 performs image cleaning but does not per- form character substitution at all. Loss level 100 is intended to provide a good compromise. Higher loss levels provide marginally better compression at the risk of unacceptable character substitutions. -verbose Display informational messages while running. REMARKS
Lossless encoding is competitive with that of the Lizardtech commercial encoders. Lossy encoding is making much progress thanks to Ilya Mezhirov from the minidjvu project. This also means that the lossy encoding perfor- mance can change from version to version. When lossy compression yields inadequate results, simply revert to only using option -clean or reduce the parameter of option -losslevel. Two features are still missing: * Half-tone detection. Collecting small marks belonging to half-tone patterns would improve compression speed. * Multi-page compression. Matching characters on several pages would improve the compression ratios for multi-page documents. CREDITS
This program was initially written by Leon Bottou <> and was improved by Bill Riemers <> and many others. The pattern matching algorithm for lossy compression was contributed by Ilya Mezhirov <>. TIFF input routines are inspired by the ones contributed by R. Keith Dennis <> and Paul Young. SEE ALSO
djvu(1), pbm(5). DjVuLibre-3.5 10/11/2001 CJB2(1)
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