You can DOCUMENT any collection in Calibre with a
Tag:
<in paper Library>, Audio book, DVD, LP
In those cases, there will not be conversion and media delivery, but your data record is in a single place.
There are tricks to get Calibre to store Audio Books, (video clips,) but remember that those are a HUGE file and Calibre Libraries are on a single Path branch (Ya might need a bigger drive). The other, is calibre stores each book format in a single container (It Zips a group of HTML) and there can only be ONE of any type container
per book. 1 Single MP3

, 22 of them