libdvdread, ifo_types.h and VIDEO_TS.IFO

I am writing an application that will automatically and reliably (!)
determine the title of a commercial DVD.  Some DVD's provide enough
information in a separate disc.id file, but others do not.  The
"Provider ID:" field in VIDEO_TS.IFO sometimes has helpful data.  But
in other cases, while there is useful information in the VIDEO_TS.IFO 
file, it is not in "Provider ID" or the other data that is defined in 
ifo_types.h and reported by libdvdread (ifo_dump).  The Sony movie 
"Radio" is an example of such a DVD.  The name of the movie and the 
studio can befound in VIDEO_TS.IFO with grep or cat, but is not reported 
by libdvdread.

Are there additional IFO types that I can add to the header file and the
libdvdread programs that will capture this additional IFO information?

Russ