Livescribe Pencast PDFs on Linux
For a course I'm taking, supplementary material is provided as Livescribe Pencast PDFs. These are PDFs recorded with a special pen, which saves audio and the pen movements. However, they only work with Adobe Reader X and above, which is not available on Linux. The following solution allows you to extract the audio as an M4A file, although not the pen movements (they are encoded in a plain-text format, though, so it should be possible to write a viewer for them).
You'll need Sejda, an open-source command-line utility (and Java library) for various PDF operations. Download sejda-console. After extracting the zip file and
cd'ing into the top directory, execute the following commands:
cd bin chmod a+x sejda-console ./sejda-console unpack -o DIRECTORY -f PDF_FILE
Now the M4A file should be in DIRECTORY.