What is a DVD?
DVD stands for Digital Video Disc Or Digital Versatile Disc. A DVD is an optical disc encoded with video and/or data and has the same appearance and dimensions of a CD but holds from 7 to 26 times more information.

What are DVD-Video, DVD-Audio and DVD-ROM?
DVD-Video contains video programs and is primarily viewed on TV. DVD-Audio can provide higher quality stereo than CD and can be played on home decks, car and portable players.
DVD-ROM contains computer data. It works much like a high capacity CD-ROM and is used almost exclusively in computers.

How much data can a DVD hold?
The DVD-ROM has four main capacities:
DVD-5: single sided/single layer (4.7GB)
DVD-9: single sided/dual layer (8.5GB)
DVD-10: double sided/single layer (9.4GB)
DVD-18: double sided/dual layer (17GB)

What Are Regional Codes?
Regional codes are used to prevent playback of discs in various geographical regions. These codes are mostly supported by the movie industry and rarely used outside of it.
There are 8 regional codes:
1: U.S., Canada, U.S. Territories
2: Europe, South Africa, Japan, and Middle East
3: Southeast Asia and East Asia
4: Central America, South America, the Caribbean, Mexico, Australia, New Zealand, and Pacific Islands.
5: Africa, Eastern Europe, Indian, North Korea, and Mongolia
6: China
7: Reserved
8: Special venues (airplanes, cruise ships, etc.)

What do you do to create a DVD?
The creation of a DVD can be simple or complicated, subject to your goals. In general, you need to collect, create and capture video, audio and data assets. The video and audio data is then compressed using software and a computer with an MPEG-2 encoder. Next menus, titles, submenus, subtitles and audio tracks are multiplexed. A DVD-R master is then created. Finally, mastering and pressing of the discs are done in a manufacturing process similar to the creation of CDs.

What is CSS?
CSS (Content Scrambling System) is an encryption scheme that prevents Hollywood movies from being digitally copied.
For more information go to DVD Demystified by Jim Taylor.