Usage

The most simple call is:

gs-parallel input.pdf page%04d.png -j4 -- -sDEVICE=png16m -dNOPAUSE -dBATCH

This converts the document input.pdf to a series of PNGs, one for each page. It splits the range of all pages in four almost equally sized ranges and forks a ghostscript instance for each of these ranges.

If there is a cluster of pages that requires an especially long render time, then it might be useful to chop the page set into more smaller chunks.

gs-parallel input.pdf page%04d.ppm -j4 --chunk-size 100 \
    -- -sDEVICE=ppmraw -dNOPAUSE -dBATCH

This will process a document with 910 pages in chunks of sizes 100, 100, …, 100, 10.

If you want a more balanced series of chunk sizes, use the option --max-chunk-size instead:

gs-parallel input.pdf page%04d.tif -j4 --max-chunk-size 100 \
    -- -sDEVICE=tif24nc -dNOPAUSE -dBATCH

It will process 10 chunks of size 91.

For selecting a subrange of pages, you must use the options --first-page and --last-page instead of the gs options -dFirstPage and -dLastPage, because gs-parallel must know the selected pages.

Known issues

We do not escape the pdf file path for page counting, this may cause problems.