I am attempting to assemble a tutorial for a graphics program. I installed 'istanbul' and that works great. The detail in the resulting ogg theora files is a bit fuzzy when played back in 'totem'. So I would like to add subtitles to the files. I found 'Gnome Subtitles' and installed that. The crux is that 'Gnome Subtitles' will not load the ogg theora files. So, am I missing some sort of extension or library for 'Gnome Subtitles'? Or do I need to convert the ogg theora files to a different format?