Imagination requires xsltproc and docbook to build. The documentation (http://imagination.sourceforge.net/download.html) usefully says that xsltproc is needed, but you also need the DocBook XSL files, otherwise the documentation fails to build with the following error:
I/O error : Attempt to load network entity http://docbook.sourceforge.net/release/xsl/current/html/onechunk.xsl
warning: failed to load external entity "http://docbook.sourceforge.net/release/xsl/current/html/onechunk.xsl"
compilation error: file ./../imagination.xsl line 7 element import
xsl:import : unable to load http://docbook.sourceforge.net/release/xsl/current/html/onechunk.xsl
To fix this, on Ubuntu you can sudo apt install docbook-xsl; there may be similar packages for other Linux OSes. It might be nice to update the documentation to say this?
Hey Stuart, thank you so much for pointing this out! It's definitely nice, thanks! At the moment the development is stalled again. I'm currently getting rid of running the ffmpeg eecutable in the background so to encode straight with libav. Thanks.