1DDJVU(1) DjVuLibre-3.5 DDJVU(1)
2
6 ddjvu - Command line DjVu decoder.
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10 ddjvu -format=fmt [options] [djvufile] [outputfile]
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14 Decode the DjVu file djvufile, produces the image file outputfile.
15 The DjVu data is read from the standard input when argument djvufile is
17 not specified or when it is equal to a single dash. Similarly, the
18 output data is written to the standard output when argument outputfile
19 is not specified or equal to a single dash. However a valid output
20 file name is always required when producing a TIFF or PDF file.
21
24 -format=fmt
25 Specify the output file formats. The recognized file formats
26 are pbm, pgm, ppm, pnm, rle, tiff, and pdf.
27 * Formats pbm, pgm, and ppm respectively produce a Portable
29 Bitmap (PBM), Portable Graymap (PGM), or Portable Pixmap
30 (PPM) file. Format pnm produces a PBM, PGM, or PPM output
31 file according to the color content of the output image.
32 * Format rle produces a compact run length encoded bitonal file
34 that is understood by the DjVuLibre commands cjb2 and
35 csepdjvu.
36 * Format tiff produces a Tagged Image Format (TIFF) file using
38 lossless compression. Enabling lossy JPEG compression (see
39 option -quality below) often produces much smaller files.
40 Commands tiffcp(1) and tiffsplit(1) are useful for manipulat‐
41 ing the resulting TIFF files.
42 * Format pdf produces a Portable Document Format (PDF) file.
44 Each page in the resulting file is represented by an image at
45 the specified resolution, using lossless compression.
46 Enabling lossy JPEG compression (see option -quality below)
47 often produces much smaller files. An alternate way to pro‐
48 duce PDF file consists in first using djvups(1) and convert
49 the resulting PostScript file to PDF. Which method gives
50 better results depends on the contents of the DJVU file and
51 on the capabilities of the PS to PDF converter.
52 When option -format is not specified, the extension of argument
54 outputfile has no influence on the default output format.
55 Instead the program behavior is modified to ensure backward com‐
56 patibility with previous versions of ddjvu. We recommend to
57 always specify the output format using this option.
58 -page=pagespec
60 Specify which pages should be decoded. When this option is not
61 specified, all pages of the documents are decoded and concate‐
62 nated into the output file. The page specification pagespec
63 contains one or more comma-separated page ranges. A page range
64 is either a page number, or two page numbers separated by a
65 dash. For instance, specification 1-10 outputs pages 1 to 10,
66 and specification 1,3,99999-4 outputs pages 1 and 3, followed by
67 all the document pages in reverse order up to page 4.
68 -eachpage
70 When this option is specified, program ddjvu generates one sepa‐
71 rate file per page named by replacing the %d specification in
72 outputfilename by the page number in a manner simular to the
73 printf(3) function.
74 -mode=mod
76 Selects which layers of the DjVu image should be rendered.
77 Valid rendering modes are color, black, mask, foreground, and
78 background.
79 * Rendering mode color is the default mode. When the DjVu file
81 is bitonal, bitonal or gray-level output is produced depend‐
82 ing on the subsampling factor. Otherwise a color image is
83 produced.
84 * Rendering mode black is useful to extract a meaningful black
86 and white image. bitonal or gray-level output is produced
87 depending on the subsampling factor.
88 * Rendering modes mask, foreground, and background select spe‐
90 cific layers of a DjVu image. These modes can fail if the
91 DjVu image does not contain the selected layer.
92 -skip Instead of aborting when encountering a corrupted page, this
94 option causes ddjvu to simply skip the corrupted page and con‐
95 tinue with the next. This is useful for processing certain dam‐
96 aged files.
97
100 The following options control the resolution of the output image. The
101 default resolution is the native resolution of the DjVu file, equiva‐
102 lent to selecting -1.
103 -n Specify an integer sub-sampling factor. The dimensions of the
105 full output image will be n times smaller than the DjVu image
106 size. The legal values for argument n range from 1 to 12.
107 Option -1, for instance, produces an output image whose resolu‐
108 tion is equal to the resolution of the input DjVu image file.
109 -subsample=n
111 This is equivalent to option -n.
112 -scale=mag
114 Specify a magnification factor relative to the resolution stored
115 in the DjVu image. Specifying magnification of 100 produces an
116 image suitable for displaying on a 100 dpi device such as a com‐
117 puter screen. The magnification factor mag can also be inter‐
118 preted as the resolution of the output image expressed in dot
119 per inch.
120 -size=wxh
122 Specify the size of the full output image. Rendering the full
123 DjVu image would create an output image whose width and height
124 would not exceed w and h. To change the aspect ratio, you must
125 also use option -aspect=no.
126 -aspect=yesno
128 This option indicates whether the image aspect ratio should be
129 preserved. The defaults is to preserve the aspect ration. This
130 option permits changes in the aspect ratio when used in combina‐
131 tion with option -size.
132
135 -verbose
136 Display informational messages describing the structure of the
137 DjVu image and the format of the output file.
138 -segment=wxh+x+y
140 Specify an image segment to render. Program ddjvu conceptually
141 renders the full page using the specified resolution, and then
142 extracts a sub-image of width w and height h, starting at posi‐
143 tion (x,y) relative to the bottom left corner of the page. Both
144 operations of course happen simultaneously. Rendering a small
145 sub-image is much faster than rendering the complete image. The
146 output file will always have size wxh when this option is speci‐
147 fied.
148 -quality=factor
150 Enables lossy JPEG compression for TIFF and PDF files. This
151 option only affects images that cannot be encoded using the pre‐
152 ferred TIFF/G4 compression. Argument factor is a quantization
153 factor ranging from 25 to 150. See command cjpeg(1) for more
154 information on JPEG quantization factors. Value 80 is a good
155 starting point.
156 -quality=uncompressed
158 Completely disables compression in TIFF and PDF files. Although
159 the resulting files are often huge, this is sometimes useful for
160 maximal compatibility with hastily written software.
161 -quality=deflate
163 Enables DEFLATE compression for TIFF files. Images that cannot
164 be encoded using the preferred TIFF/G4 compression will be
165 encoded with DEFLATE compression if available. Otherwise the
166 more portable PACKBITS compression is used. Specifying this
167 option is not necessary for PDF files because this is the
168 default behavior.
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172 Various options have been maintained to ensure backward compatibility
173 with previous versions of ddjvu. When option -format is not specified,
174 the program only decodes the first page of the document and the default
175 resolution becomes -scale=100. Options -size, -scale, -segment, and
176 -page accept an argument separated by a space. Options -foreground,
177 -background, and -black are shorthands for the -mode=mod option.
178 Please do not rely on these features.
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183 Command
184 ddjvu -format=tiff myfile.djvu myfile.tif
186 decodes all pages and produces a multipage TIFF file.
188 Command
190 ddjvu -format=ppm -page=1-10 -eachpage -size=100x100 myfile.djvu
192 thumb%03d.ppm
193 produces 100x100 thumbnails for the first ten page of a document and
195 outputs them as PPM files named thumb001.ppm to thumb010.ppm.
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199 The new version of this program was written by Léon Bottou
200 <leonb@users.sourceforge.net>.
201 This program includes code derived from program tiff2pdf, written by
203 Ross Finlayson and released under a BSD license.
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207 djvu(1), djview(1), pnm(5), pbm(5), pgm(5), ppm(5), cjpeg(1), tiffs‐
208 plit(1), tiffcp(1), printf(3)
209DjVuLibre-3.5 10/19/2002 DDJVU(1)