Sorry to be so late commenting on this, but there seems to be some confusion. I
am a video professional, so perhaps I can clear it up.

An ISO is a disk image, that can contain various types of data, from a distro,
to a bunch of photos. It can normally be mounted as a virtual drive.

When it comes to burning a DVD in the correct format for a domestic DVD player,
the movie(s) must be "authored". DeVeDe will do this for you, and when you look
inside the image it creates, you will see a VIDEO_TS folder and an AUDIO_TS
folder - the AUDIO_TS will be empty because that's for multiple languages. In
the VIDEO_TS folder you will see various files, including .VOB files - these are
in fact Mpeg-2 files, created by the authoring program, but the whole structure
is how your DVD player expects to find it.

Don't worry about country codes - by default it will have region 0 which is all
countries. (I'm not sure how/if you can set region codes in DeVeDe).

There is a tutorial on using DeVeDe as an authoring tool at
http://www.my-guides.net/en/content/view/75/