The very last step in creating a DVD compliant direcory structure.
Very nearly all DVD authoring processes end with the two commands:
dvdauthor -t -o my-dvd-directory -c 0;15:00,30:00,45:00 my-movie.mpg
dvdauthor -T -o my-dvd-directory
Or something similar.
dvdauthor is well documented HERE: http://dvdauthor.sourceforge.net/doc/index.html
Note that when running 24fps progressive content through dvdauthor, some warnings regarding alignment and framerate will be generated. These warnings are harmless... In fact, they are utterly wrong. So go ahead and make 24fps progressive dvd's!