dvdunauthor performs the opposite task to dvdauthor: given the files making up a DVD-Video title, it separates out the individual menus and titles into separate MPEG files, and constructs an XML file that dvdauthor can use to put them together again.
spuunmux performs the opposite task to spumux: given an MPEG-2 file containing a subpicture or menu definition, it extracts the subpicture layer into separate PNG files, and creates an XML file that spumux can use to put them together again.
mpeg2desc can produce a dump of the types of packet headers present in an MPEG file, and also extract audio and video streams into separate files.
dvddirdel is a simple script to perform safe deletion of an output directory and its contents as created by a previous run of dvdauthor. It is safer than “rm -rf” in that it only deletes the directories and files that would form part of a DVD-Video directory structure, and nothing else. This way, if you accidentally specify the wrong directory to delete, it will more likely fail with an error, than cause you to lose important data.
spumux embeds information in the MPEG files it generates in a private format that is decoded by dvdauthor for use in controlling generation of the final output files:
Note a subtle point: menus can have 4 different colours, and the colours can be different between the different states of normal, highlighted and selected. But there is only one subpicture image shared between these three states, and having 2 bits per pixel, it is restricted to 4 different pixel values. Thus, even though you specify the appearance of the states with separate image files, spumux combines them into one and will flag an error if the result cannot be represented within 2 bits per pixel.
dvdunauthor and spuunmux are very useful for trying to understand the structure of existing DVD-Video titles. Note, however, that dvdunauthor puts some additional tags into the XML files it creates that the current version (0.6.14) of dvdauthor doesn't understand.
Additional useful information about DVDAuthor has been collected at the DVDAuthor Wiki.