How do I convert a DjVu document to PDF in Linux using only command line tools?

Question

I've got some documents in DjVu which I'll like convert to PDF. Is there a way to do this using command line OSS tools?

Answer 1

djvu2pdf should fit the bill, it's a small script that makes use of the djvulibre toolset. If not, there are other methods that require multiple command-line tools.

Answer 2

The ddjvu program (which is part of the standard djvulibre package) will do this:

$ ddjvu -format=pdf -quality=85 -verbose a.djvu a.pdf

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Warning: this produces large files (but PDF files made by Christoph Sieghart's script are of the same size).

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I also wrote the following small shell script some years ago.  It does the same automatically. (Save this as djvu2pdf.sh.)

#!/bin/sh

# convert DjVu -> PDF
# usage:  djvu2pdf.sh  <file.djvu>

i="$1"
echo "------------ converting $i to PDF ----------------";
o="$(basename "$i" .djvu).pdf"
echo "[ writing output to $o ] "

ddjvu -format=pdf -quality=85 -verbose "$i" "$o"

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The djvu2pdf script by Christoph Sieghart does essentially the same.

Answer 3

$ djvups input.djvu | ps2pdf - output.pdf

In my case the output file was 10x smaller than with ddjvu. Both djvups and ps2pdf present in ubuntu repository.

$ sudo apt-get install djvulibre-bin ghostscript

I've found this method in man ddjvu, so always read manuals ;)

An alternate way to produce 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.

Answer 4

What about simply using DJView and export as PDF?

1. Goto Synaptic Package Manager (System - Administration - Synaptic Package Manager)
2. Install DJview4
3. Run DJview (Applications - Graphics - DJView4)
4. Open your .djvu document
5. Menu - Export As: PDF

Look at http://art.ubuntuforums.org/showthread.php?t=1232038

Answer 5

If you don't care about colors and images you can get much smaller files if you drop the colors and use instead:

ddjvu -format=pdf -mode=black input.djvu output.pdf

Texts, codes and formulas looks perfectly, but most of the images are gone

Answer 6

I've changed the @Maxim script a little ...

#!/bin/bash
# convert DjVu -> PDF
# usage:  djvu2pdf.sh [-q quality | -b] <infile.djvu> [outfile.pdf]

mode='color'
quality=80

aparse() {
  while [ $# != 0 ] ; do
    case "$1" in
    -q|--quality)
      quality=${2}
      shift
      ;;
    -b|--black)
      mode='black'
      ;;
  esac
  shift
done
}
aparse "$@"

i="$1"
o=${2:-$(basename $i .djvu).pdf}
if [ -f  "$o" ]; then 
  echo "file $o exists, override [Y/n]?"
  read ans
  case "$ans" in 
   n|N) exit 1;;
  esac
fi
echo "[ converting $i to $o ] "

cmd="ddjvu -format=pdf -quality=$quality -mode=$mode -verbose $i $o "

echo "[ executing $cmd ] "
$cmd

Answer 7

For MacOS users you can install djvu2pdf like this:

$brew install djvu2pdf 

How to use it(works for any Xnix like system):

$djvu2pdf nameBook.djvu nameBookToCreate.pdf

Answer 8

For an approach that preserves the text layer¹ one can use djvu2pdf described in this answer. The general approach is described here or here.

For macOS a minor tweak is required.

BSD readlink -f behaviour differs from GNU readlink. This can be fixed by installing GNU coreutuils and changing readlink -f to greadlink -f.

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_{1. According to the description the table of contents will also be preserved, but I haven't tested that.}