In the beginning, it took years for movies, TV shows, other video programming, and computer software to become widely available.

Today, people attempt to create DVD's on thier home or office computers. These discs are not designed for mass distribution. Vagueness of spec. and inadequate testing of players and discs has resulted in incompatibilities. Some discs don't function fully (or don't play at all) on some players. Some DVD's have built-in copy protection and regional lockout. DVD uses digital compression. Poorly compressed audio or video may be blocky, fuzzy, harsh, or vague.
The audio down-mix process for stereo/Dolby Surround can reduce dynamic range. Some DVD players and drives may not be able to read DVD-R's. Very few players can play in reverse at normal speed.