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rgb2ycbcr
=========
.. program:: rgb2ycbcr
Synopsis
--------
**rgb2ycbcr** [ *options* ] *src1.tif src2.tif … dst.tif*
Description
-----------
:program:`rgb2ycbcr` converts RGB color, greyscale, or bi-level TIFF
images to YCbCr images by transforming and sampling pixel data. If multiple
files are specified on the command line each source file is converted to a
separate directory in the destination file.
By default, chrominance samples are created by sampling
2 by 2 blocks of luminance values; this can be changed with the
:option:`-h` and :option:`-v` options.
Output data are compressed with the ``PackBits``
compression scheme, by default; an alternate scheme can be selected with the
:option:`-c` option.
By default, output data are compressed in strips with
the number of rows in each strip selected so that the
size of a strip is never more than 8 kilobytes;
the :option:`-r`
option can be used to explicitly set the number of
rows per strip.
Options
-------
.. option:: -c compress
Specify a compression scheme to use when writing image data:
:command:`-c none` for no compression,
:command:`-c packbits` for the PackBits compression algorithm (the default),
:command:`-c jpeg` for the JPEG compression algorithm,
:command:`\-c zip` for the deflate compression algorithm, and
:command:`-c lzw` for Lempel-Ziv & Welch.
.. option:: -h size
Set the horizontal sampling dimension to one of: 1, 2 (default), or 4.
.. option:: -r striprows
Write data with a specified number of rows per strip;
by default the number of rows/strip is selected so that each strip
is approximately 8 kilobytes.
.. option:: -v size
Set the vertical sampling dimension to one of: 1, 2 (default), or 4.
See also
--------
:doc:`tiffinfo` (1),
:doc:`tiffcp` (1),
:doc:`/man/libtiff` (3tiff)
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