afiq.hamzah
153 lines
6.5 KiB
Plaintext
153 lines
6.5 KiB
Plaintext
GIF2WEBP(1) General Commands Manual GIF2WEBP(1)
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NAME
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gif2webp - Convert a GIF image to WebP
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SYNOPSIS
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gif2webp [options] input_file.gif -o output_file.webp
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DESCRIPTION
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This manual page documents the gif2webp command.
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gif2webp converts a GIF image to a WebP image.
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OPTIONS
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The basic options are:
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-o string
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Specify the name of the output WebP file. If omitted, gif2webp
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will perform conversion but only report statistics. Using "-"
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as output name will direct output to 'stdout'.
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-- string
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Explicitly specify the input file. This option is useful if the
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input file starts with an '-' for instance. This option must ap-
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pear last. Any other options afterward will be ignored. If the
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input file is "-", the data will be read from stdin instead of a
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file.
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-h, -help
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Usage information.
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-version
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Print the version number (as major.minor.revision) and exit.
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-lossy Encode the image using lossy compression.
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-mixed Mixed compression mode: optimize compression of the image by
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picking either lossy or lossless compression for each frame
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heuristically.
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-q float
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Specify the compression factor for RGB channels between 0 and
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100. The default is 75.
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In case of lossless compression (default), a small factor en-
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ables faster compression speed, but produces a larger file. Max-
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imum compression is achieved by using a value of 100.
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In case of lossy compression (specified by the -lossy option), a
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small factor produces a smaller file with lower quality. Best
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quality is achieved by using a value of 100.
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-m int Specify the compression method to use. This parameter controls
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the trade off between encoding speed and the compressed file
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size and quality. Possible values range from 0 to 6. Default
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value is 4. When higher values are used, the encoder will spend
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more time inspecting additional encoding possibilities and de-
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cide on the quality gain. Lower value can result is faster pro-
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cessing time at the expense of larger file size and lower com-
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pression quality.
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-min_size
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Encode image to achieve smallest size. This disables key frame
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insertion and picks the dispose method resulting in the smallest
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output for each frame. It uses lossless compression by default,
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but can be combined with -q, -m, -lossy or -mixed options.
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-kmin int
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-kmax int
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Specify the minimum and maximum distance between consecutive key
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frames (independently decodable frames) in the output animation.
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The tool will insert some key frames into the output animation
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as needed so that this criteria is satisfied.
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A 'kmax' value of 0 will turn off insertion of key frames. A
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'kmax' value of 1 will result in all frames being key frames.
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'kmin' value is not taken into account in both these special
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cases. Typical values are in the range 3 to 30. Default values
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are kmin = 9, kmax = 17 for lossless compression and kmin = 3,
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kmax = 5 for lossy compression.
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These two options are relevant only for animated images with
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large number of frames (>50).
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When lower values are used, more frames will be converted to key
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frames. This may lead to smaller number of frames required to
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decode a frame on average, thereby improving the decoding per-
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formance. But this may lead to slightly bigger file sizes.
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Higher values may lead to worse decoding performance, but
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smaller file sizes.
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Some restrictions:
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(i) kmin < kmax,
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(ii) kmin >= kmax / 2 + 1 and
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(iii) kmax - kmin <= 30.
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If any of these restrictions are not met, they will be enforced
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automatically.
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-metadata string
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A comma separated list of metadata to copy from the input to the
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output if present. Valid values: all, none, icc, xmp. The de-
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fault is xmp.
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-f int For lossy encoding only (specified by the -lossy option). Spec-
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ify the strength of the deblocking filter, between 0 (no filter-
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ing) and 100 (maximum filtering). A value of 0 will turn off
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any filtering. Higher value will increase the strength of the
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filtering process applied after decoding the picture. The higher
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the value the smoother the picture will appear. Typical values
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are usually in the range of 20 to 50.
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-mt Use multi-threading for encoding, if possible.
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-loop_compatibility
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If enabled, handle the loop information in a compatible fashion
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for Chrome version prior to M62 (inclusive) and Firefox.
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-v Print extra information.
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-quiet Do not print anything.
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BUGS
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Please report all bugs to the issue tracker:
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https://bugs.chromium.org/p/webp
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Patches welcome! See this page to get started: https://www.webmpro-
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ject.org/code/contribute/submitting-patches/
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EXAMPLES
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gif2webp picture.gif -o picture.webp
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gif2webp -q 70 picture.gif -o picture.webp
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gif2webp -lossy -m 3 picture.gif -o picture_lossy.webp
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gif2webp -lossy -f 50 picture.gif -o picture.webp
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gif2webp -q 70 -o picture.webp -- ---picture.gif
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cat picture.gif | gif2webp -o - -- - > output.webp
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AUTHORS
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gif2webp is a part of libwebp and was written by the WebP team.
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The latest source tree is available at https://chromium.google-
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source.com/webm/libwebp
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This manual page was written by Urvang Joshi <urvang@google.com>, for
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the Debian project (and may be used by others).
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SEE ALSO
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cwebp(1), dwebp(1), webpmux(1)
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Please refer to https://developers.google.com/speed/webp/ for addi-
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tional information.
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November 17, 2021 GIF2WEBP(1)
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