If you prefer the command line, the "growisofs" command is the open source dvd burner for you. It can burn any type of information to a DVD just by changing the options. Actually, it's the backend DVD utility for both K3b and Brasero (and most other open source DVD burners).
To burn an .iso file to a dvd, you would use the command:
growisofs -dvd-compat -Z /dev/hdc=file.iso
If you want to store a set of directories and files on a DVD () without first storing an image on the hard drive you would use the command:
growisofs -Z /dev/dvd -J -R path_to_disc_root
If you are burning a video DVD, the command would be:
growisofs -Z /dev/dvd -dvd-video path_to_video_root
In the case of the video DVD, the video root would hold the Audio_TS and Video_TS files for the video.