For DVDs, authoring involves the assembling of assets (video, film, stills, menus, audio) into a format compliant with the DVD specification. The DVD specification is a series of guidelines created by the DVD Forum. The DVD forum is a collection of hardware manufacturers, software firms, and content providers. The specification is a set of rigorous standards and guidelines created to help ensure compatibility and unity with all DVD players and DVD content. Although the specification has clear guidelines, there are still authoring programs and DVD players that may not follow all of the specifications to the letter. This can result in DVDs that may not play or may not play the way the author intended.
Videotapes and QuickTime/AVI files are not ready as is to use in DVDs. Their files sizes are large, 101GB for an hour of uncompressed or 11GB for DV, and cannot fit on a 4.8 GB DVD-5 or a 8.5 GB DVD-9. To make these large files small enough to fit on a DVD, they must be encoded or compressed. The proper format to compress for DVD is the Mpeg2 format – the required standard for Standard Definition (SD) DVDs. This process can be accomplished utilizing either hardware or software encoding.