I read this on some IT news site not so long ago.
6th main version of DivX will bring DVD-like menu system, and it will be compatible with the current hardware players. With the new compression engine the produced file size will 25-50% smaller than the concurent codecs (marketing...?) Most important for us, there will be a possiblility to integrate sub files into the media file (I dunno sub groups will use this method). The current beta testing will end (hopefully) in march.
They say nothing about image quality.