xine-lib lives in the early noughts. Text subtitles need to be local files, and because of libdvdread, DVD images and directories need to be on the local filesystem as well.
Well, Totem now has support for both of those on remote locations, thanks to the fuse support in gvfs. All the code's in trunk, although you probably want to wait for me to unbreak totem-pl-parser's port to GIO first ;)