NAME

       didjvu - DjVu encoder with foreground/background separation

SYNOPSIS

       didjvu separate [{-o | --output} output-mask] [option...] input-image

       didjvu separate --output-template name-template  [option...] input-image...

       didjvu encode [{-o | --output} output-djvu] [option...] input-image

       didjvu encode --output-template name-template  [option...] input-image...

       didjvu bundle [{-o | --output} output-djvu] [option...] input-image...

       didjvu {--version | --help | -h}

DESCRIPTION

       didjvu uses the Gamera[1] framework to separate foreground/background layers, which can be
       then encoded into a DjVu file.

       didjvu separate generates images mask(s) for the supplied input image(s). Masks are saved
       in the PNG format.

       didjvu encode converts the supplied input image(s) to single-page DjVu documents(s).

       didjvu bundle converts the supplied input image(s) to a bundled multi-page DjVu document.

OPTIONS

       didjvu accepts the following options:

   Input, output
       -o, --output=output-djvu
           Generate a bundled multi-page document. Write the file into output-djvu file instead
           of standard output.

           For separate and encode commands this option is allowed only if there is exactly one
           input file (i.e. exactly one output file).

       --output-template=template
           Specifies the naming scheme for output files for the separate and encode commands.
           Please consult the “TEMPLATE LANGUAGE” section for the template language description.

           This option is mandatory if there is more than one input file (i.e. more than one
           output file).

       --pageid-template=template
           Specifies the naming scheme for page identifiers for the bundle command. Please
           consult the “TEMPLATE LANGUAGE” section for the template language description. The
           default template is “{base-ext}.djvu”.

           For portability reasons, page identifiers:

           •   must consist only of lowercase ASCII letters, digits, _, +, - and dot,

           •   cannot start with a +, - or a dot,

           •   cannot contain two consecutive dots,

           •   must end with the .djvu extension.

   Masks
       --loss-level=n
           Specifies the aggressiveness of the lossy compression for the separate and encode
           commands. The default is 0 (lossless). Valid values are integers between 0 and 200,
           inclusive.

           This option is similar to the -losslevel option of cjb2; please consult the cjb2(1)
           manual page for details.

       --lossless
           Synonym for --loss-level=0.

       --clean
           Synonym for --loss-level=1.

       --lossy
           Synonym for --loss-level=100.

       -m, --method=method
           Use the selected method to generate image mask (i.e. separate foreground from
           background). The following methods should be available:

           abutaleb
               Abutaleb locally-adaptive thresholding algorithm

           bernsen
               Bernsen thresholding algorithm

           brink
               Brink and Pendock's minimum-cross entropy method

                   Note
                   this method requires Gamera ≥ 3.4.0

           djvu
               DjVu thresholding algorithm

           niblack
               Niblack adaptive thresholding algorithm

           otsu
               Otsu thresholding algorithm

           sauvola
               Sauvola adaptive thresholding algorithm

           shading-subtraction
               thresholds an image after subtracting a possibly shaded background

                   Note
                   this method requires Gamera ≥ 3.3.1

           tsai
               splitting along a threshold value determined using the Tsai Moment Preserving
               Threshold algorithm

           white-rohrer
               White and Rohrer dynamic thresholding algorithm

           The default is ‘djvu’.

           Please consult the Gamera documentation[2] for details.

       -p, --pages-per-dict=n
           For bundle command: if n > 1, compress mask using minidjvu using n pages in one pass.
           The default is 1.

       --masks, --mask=input-mask
           Use the pre-generated image masks for the encode and bundle commands.

   Foreground/background quality, resolution
       (These options apply to encode and bundle commands only.)

       -d, --dpi=resolution
           Specifies the desired resolution to resolution dots per inch. The default is 300 dpi.
           The allowed range is: 72 ≤ resolution ≤ 6000.

       --fg-slices=n
           Specifies the encoding quality of the IW44 foreground layer. The default is 100.

           This option is similar to the -slice option of c44; please consult the c44(1) manual
           page for details.

       --fg-crcb=normal
           Select normal chrominance encoding of the foreground layer.

       --fg-crcb=half
           Select half resolution chrominance encoding of the foreground layer.

       --fg-crcb=full
           Select the highest possible quality for encoding the chrominance information of the
           foreground layer. This is the default.

       --fg-crcb=none
           Disable the encoding of the chrominance of the foreground layer.

       --fg-subsample=n
           Specifies the foreground/background subsampling ratio. The default is 6. Valid values
           are integers between 1 and 12, inclusive.

       --bg-slices=n+...+n, --bg-slices=n,...,n
           Specifies the encoding quality of the IW44 background layer. The default is 74+10+6+7.

           This option is similar to the -slice option of c44; please consult the c44(1) manual
           page for details.

       --bg-crcb=normal
           Select normal chrominance encoding of the background layer. This is the default.

       --bg-crcb=half
           Select half resolution chrominance encoding of the background layer.

       --bg-crcb=full
           Select the highest possible quality for encoding the chrominance information of the
           background layer.

       --bg-crcb=none
           Disable the encoding of the chrominance of the background layer.

       --bg-subsample=n
           Specifies the foreground/background subsampling ratio. The default is 3. Valid values
           are integers between 1 and 12, inclusive.

   XMP support
       (These options apply to encode and bundle commands only.)

       --xmp
           Create sidecar XMP[3] metadata.

               Note
               This option is experimental!

   Verbosity, help
       -v, --verbose
           Display more informational messages while converting the file.

       -q, --quiet
           Don't display informational messages while converting the file.

       --version
           Output version information and exit.

       -h, --help
           Display help and exit.

ENVIRONMENT

       The following environment variables affects didjvu:

       TMPDIR

           didjvu makes havy use of temporary files. It will store them in a directory specified
           by this variable. The default is /tmp.

TEMPLATE LANGUAGE

   Template syntax
       The template language uses the Python string formatting syntax[4].

   Available field names
       name
           Input file path.

       name-ext
           Input file path without file extension.

       base
           Input file name without directory components.

       base-ext
           Input file name without directory components and without file extension.

       page, page+N, page-N
           Page number, optionally offseted by a number N.

SEE ALSO

       djvu(1), djvumake(1), c44(1), cjb2(1), minidjvu(1),

NOTES

        1. Gamera
           http://gamera.informatik.hsnr.de/

        2. Gamera documentation
           http://gamera.sourceforge.net/doc/html/binarization.html

        3. XMP
           http://www.adobe.com/devnet/xmp.html

        4. Python string formatting syntax
           http://docs.python.org/library/string.html#format-string-syntax