Seriously, screw Theora. None of the tools work. Really, there's no reason to go beyond that at all. ffmpeg can't create working Ogg Theora files for no discernible reason. The makers of Theora don't provide an encoder, so it's not like you can just use theirs! The only working Theora tool appears to be ffmpeg2theora - which is completely useless because it can't be used to remux streams.
The one thing Xiph does provide, a tool for creating Ogg streams, doesn't create working streams. Making it completely useless as well.
So, the Ogg container itself is completely useless, none of Xiph's tools produce working streams, and the only reason I have to use this brain-dead abortion of a codec is because Opera and Firefox refuse to use system codecs for video.
Thanks a lot, pals.
Thankfully the next version of Firefox will contain WebM support, which has one major advantage over Theora: it fucking works.
Of course, all this is really moot anyway, since there's no real reason to use these stupid codecs in any case since Firefox and Opera should just license the H.264 codec that everyone already uses anyway and be done with it. The only reason to even play with WebM is because they refuse to.