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ddjvu(1)                         DjVuLibre-3.5                        ddjvu(1)




NAME

       ddjvu - Command line DjVu decoder.



SYNOPSIS

       ddjvu -format=fmt [options] [djvufile] [outputfile]



DESCRIPTION

       Decode the DjVu file djvufile, produces the image file outputfile.

       The DjVu data is read from the standard input when argument djvufile is
       not specified or when it is equal to a  single  dash.   Similarly,  the
       output  data is written to the standard output when argument outputfile
       is not specified or equal to a single dash.   However  a  valid  output
       file name is always required when producing a TIFF or PDF file.



MAIN OPTIONS

       -format=fmt
              Specify  the  output  file formats.  The recognized file formats
              are pbm, pgm, ppm, pnm, rle, tiff, and pdf.

              *  Formats pbm, pgm, and ppm  respectively  produce  a  Portable
                 Bitmap  (PBM),  Portable  Graymap  (PGM),  or Portable Pixmap
                 (PPM) file.  Format pnm produces a PBM, PGM,  or  PPM  output
                 file according to the color content of the output image.

              *  Format rle produces a compact run length encoded bitonal file
                 that  is  understood  by  the  DjVuLibre  commands  cjb2  and
                 csepdjvu.

              *  Format  tiff produces a Tagged Image Format (TIFF) file using
                 lossless compression.  Enabling lossy JPEG  compression  (see
                 option  -quality  below)  often  produces much smaller files.
                 Commands tiffcp(1) and tiffsplit(1) are useful for manipulat-
                 ing the resulting TIFF files.

              *  Format  pdf  produces  a Portable Document Format (PDF) file.
                 Each page in the resulting file is represented by an image at
                 the   specified   resolution,   using  lossless  compression.
                 Enabling lossy JPEG compression (see option  -quality  below)
                 often  produces much smaller files.  An alternate way to pro-
                 duce PDF file consists in first using djvups(1)  and  convert
                 the  resulting  PostScript  file  to PDF.  Which method gives
                 better results depends on the contents of the DJVU  file  and
                 on the capabilities of the PS to PDF converter.

              When  option -format is not specified, the extension of argument
              outputfile has  no  influence  on  the  default  output  format.
              Instead the program behavior is modified to ensure backward com-
              patibility with previous versions of  ddjvu.   We  recommend  to
              always specify the output format using this option.

       -page=pagespec
              Specify  which pages should be decoded.  When this option is not
              specified, all pages of the documents are decoded  and  concate-
              nated  into  the  output  file.  The page specification pagespec
              contains one or more comma-separated page ranges.  A page  range
              is  either  a  page  number,  or two page numbers separated by a
              dash.  For instance, specification 1-10 outputs pages 1  to  10,
              and specification 1,3,99999-4 outputs pages 1 and 3, followed by
              all the document pages in reverse order up to page 4.

       -eachpage
              When this option is specified, program ddjvu generates one sepa-
              rate  file  per  page named by replacing the %d specification in
              outputfilename by the page number in a  manner  simular  to  the
              printf(3) function.

       -mode=mod
              Selects  which  layers  of  the  DjVu  image should be rendered.
              Valid rendering modes are color, black,  mask,  foreground,  and
              background.

              *  Rendering mode color is the default mode.  When the DjVu file
                 is bitonal, bitonal or gray-level output is produced  depend-
                 ing  on  the  subsampling factor.  Otherwise a color image is
                 produced.

              *  Rendering mode black is useful to extract a meaningful  black
                 and  white  image.   bitonal or gray-level output is produced
                 depending on the subsampling factor.

              *  Rendering modes mask, foreground, and background select  spe-
                 cific  layers  of  a DjVu image.  These modes can fail if the
                 DjVu image does not contain the selected layer.

       -skip  Instead of aborting when encountering  a  corrupted  page,  this
              option  causes  ddjvu to simply skip the corrupted page and con-
              tinue with the next.  This is useful for processing certain dam-
              aged files.



RESOLUTION OPTIONS

       The  following options control the resolution of the output image.  The
       default resolution is the native resolution of the DjVu  file,  equiva-
       lent to selecting -1.

       -n     Specify  an  integer sub-sampling factor.  The dimensions of the
              full output image will be n times smaller than  the  DjVu  image
              size.   The  legal  values  for  argument  n range from 1 to 12.
              Option -1, for instance, produces an output image whose  resolu-
              tion is equal to the resolution of the input DjVu image file.

       -subsample=n
              This is equivalent to option -n.

       -scale=mag
              Specify a magnification factor relative to the resolution stored
              in the DjVu image.  Specifying magnification of 100 produces  an
              image suitable for displaying on a 100 dpi device such as a com-
              puter screen.  The magnification factor mag can also  be  inter-
              preted  as  the  resolution of the output image expressed in dot
              per inch.

       -size=wxh
              Specify the size of the full output image.  Rendering  the  full
              DjVu  image  would create an output image whose width and height
              would not exceed w and h.  To change the aspect ratio, you  must
              also use option -aspect=no.

       -aspect=yesno
              This  option  indicates whether the image aspect ratio should be
              preserved.  The defaults is to preserve the aspect ration.  This
              option permits changes in the aspect ratio when used in combina-
              tion with option -size.



OTHER OPTIONS

       -verbose
              Display informational messages describing the structure  of  the
              DjVu image and the format of the output file.

       -segment=wxh+x+y
              Specify  an image segment to render.  Program ddjvu conceptually
              renders the full page using the specified resolution,  and  then
              extracts  a sub-image of width w and height h, starting at posi-
              tion (x,y) relative to the bottom left corner of the page.  Both
              operations  of  course happen simultaneously.  Rendering a small
              sub-image is much faster than rendering the complete image.  The
              output file will always have size wxh when this option is speci-
              fied.

       -quality=factor
              Enables lossy JPEG compression for TIFF  and  PDF  files.   This
              option only affects images that cannot be encoded using the pre-
              ferred TIFF/G4 compression.  Argument factor is  a  quantization
              factor  ranging  from  25 to 150.  See command cjpeg(1) for more
              information on JPEG quantization factors.  Value 80  is  a  good
              starting point.

       -quality=uncompressed
              Completely disables compression in TIFF and PDF files.  Although
              the resulting files are often huge, this is sometimes useful for
              maximal compatibility with hastily written software.

       -quality=deflate
              Enables  DEFLATE compression for TIFF files.  Images that cannot
              be encoded using  the  preferred  TIFF/G4  compression  will  be
              encoded  with  DEFLATE  compression if available.  Otherwise the
              more portable PACKBITS compression  is  used.   Specifying  this
              option  is  not  necessary  for  PDF  files  because this is the
              default behavior.



DEPRECATED OPTIONS

       Various options have been maintained to ensure  backward  compatibility
       with previous versions of ddjvu.  When option -format is not specified,
       the program only decodes the first page of the document and the default
       resolution  becomes  -scale=100.   Options -size, -scale, -segment, and
       -page accept an argument separated by a  space.   Options  -foreground,
       -background,  and  -black  are  shorthands  for  the  -mode=mod option.
       Please do not rely on these features.




EXAMPLES

       Command

          ddjvu -format=tiff myfile.djvu myfile.tif

       decodes all pages and produces a multipage TIFF file.

       Command

          ddjvu -format=ppm  -page=1-10  -eachpage  -size=100x100  myfile.djvu
          thumb%03d.ppm

       produces  100x100  thumbnails  for the first ten page of a document and
       outputs them as PPM files named thumb001.ppm to thumb010.ppm.



CREDITS

       The  new  version  of  this  program  was  written   by   Leon   Bottou
       <leonb@users.sourceforge.net>.

       This  program  includes  code derived from program tiff2pdf, written by
       Ross Finlayson and released under a BSD license.



SEE ALSO

       djvu(1), djview(1), pnm(5), pbm(5), pgm(5),  ppm(5),  cjpeg(1),  tiffs-
       plit(1), tiffcp(1), printf(3)



DjVuLibre-3.5                     10/19/2002                          ddjvu(1)

djvulibre 3.5.27 - Generated Sat Mar 14 16:37:01 CDT 2015
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