This tool can copy a single or all title sets from a DVD to a directory. It is
important to note that complete title sets and not only VOB parts of a title
are copied. You have the exact image or clone of the source title set with this
tool. It does no fancy IFO parsing, only raw DVD block are read.

Why? If you want to use libdvdread or derived applications (e.g. transcode) in
the DVD image mode (i.e. you have a directory on your hard disk with a DVD
structure on it) then you must have a copy of the full title set for your
desired title. If you only extract the VOB information belonging to a title
plus the *.IFO files then the references in the *.IFO files are not correct,
because they assume the full title set is still available.

It is a companion tool for cpdvd that offers more user-friendly copy options
(e.g. you can pass the title number and not the title set number).