I patched MediaTomb to use MediaInfo library (http://mediainfo.sourceforge.net) instead of ffmeg for meta data retrieval from MM files. As it was explicitly developed for this purpose it seems to be much more powerful and flexible than ffmpeg on this topic.
The attached patch is for mediatomb-0.11.0-0.pm.4.src.rpm (Suse / Fedora). Unfortunately I'm not firm in writing configure scripts, so the dynamic lib/include checking is missing (if somebody was so friendly to finish this), one need to install libmediainfo manually (libmediainfo0-0.7.16-0.pm.1 from Packman repository f.i.) too.