On ubuntu systems, you’ll need the following packages: genisoimage and dvd+rw-tools.
If you have a folder named “mydvd” in your home directory containing a VIDEO_TS folder, cd to your home folder mydvd, then run:
mkisofs -dvd-video -o mydvd.iso mydvd
This will produce a mydvd.iso file. To verify, run
isoinfo -l -i mydvd.iso