Indeed, the DVD-9 was originally called that way 'cause it can hold up to 9 Gb of data (unformatted, 8.5 formatted) and DVD-5 was called that way because of the same thing with the 4.7Gb disks (which actually can hold up to 4.4Gb when formatted). I have not heard of any tools to help you author DVDs... I know you could capture a home-made video (like a vacation one, for instance) on the coputer and then using tools like cinelerra be able to make the video DVD suitable, but you'd still have to use other tools (Mac or Windows tools) to make the menus and then burn it... So I'm deffinitely going to check this out as DVD authoring at a more reasonable price would be cool (not to mention useful for some purposes other than entertainment).

I personally have tried XDVDShrink, k3b, and DVDShrink through. XDVDShrink works about 98% of the time, some DVD's just cannot be copied, I guess the encryption is too great. Also, it will not copy the DVD menus, and I had trouble getting the subtittles to work. K3b will not copy encrypted DVD's! I have had the most success with using DVDShrink through wine, this will rip and encode the DVD to your hard drive, from there I use K3b to write the DVD. This will give you a complete backup of your movies, including Menus, and subtittles. You can also select certain features to exclude allowing you to have more space on the DVD giving you better video quality. I usually exclude french audio or any other languages I don't speak.

There are so many free dvdauthoring tools for linux tripping over one in a google search can't be helped.

tovid at http://tovid.sourceforge.net/

dvdauthor at http://dvdauthor.sourceforge.net/

gui for dvdauthor at http://www.videohelp.com/~gfd/

dvdstyler at http://dvdstyler.sourceforge.net/

kdvdauthhor at http://pingwing.xs4all.nl/view.php/page/DVDAuthor

dvdslideshow makes picture DVD's at http://dvd-slideshow.sourceforge.net/

varsha at http://varsha.sourceforge.net/

Personally I like tovid with the tovid gui