This article is from the DVD Formats FAQ, by jtfrog@usa.net (Jim Taylor) with numerous contributions by others.
The black bars are part of the letterbox process (see 3.5), and in many
cases you can't get rid of them. If you set the display option in your
player to pan & scan (sometimes called fullscreen or 4:3) instead of
letterbox, it won't do you much good since no DVD movies have been released
with this feature enabled.
In some cases, there may be both a fullscreen and a letterbox version of
the movie on the same disc, with a variety of ways to get to the fullscreen
version (usually only one works, so you may have to try all three):
1. Check the other side of the disc (if it's two-sided)
2. Look for a fullscreen choice in the main menu
3. Use the "aspect" button on the remote control
DVD was designed to make movies look as good as possible on TV. Since most
movies are wider than most TVs, letterboxing preserves the format of the
theatrical presentation. (Nobody complains that the top and bottom of the
picture are cut off in theaters.) DVD is ready for TVs of the future, which
are widescreen. For these and other reasons, many movies on DVD are only
available in widescreen format.
Note: Most widescreen movies use 1.85 ("flat") aspect ratio. In this case,
the actual size of the images on your TV are the same for a letterbox
version and a full-frame version, unless the pan & scan processed is used
(which cuts out parts of the picture). In other words, the picture is
usually the same size, with extra stuff visible at the the top and bottom
in the fullscreen version. In more other words, letterboxing covers over
the part of the picture that was also covered in the theater (1.85 movies),
or it allows the entire widescreen picture to visible (2.35 movies).
For a detailed explanation of why most movie fans prefer letterboxing, see
the Widescreen Cinema page and the Letterbox/Widescreen Advocacy Page. For
an explanation of anamorphic widescreen and links to more information on
other Web sites, see 3.5. For an anti-letterboxing viewpoint, see the FAQ
About Letterboxing (Letterschlocking), after which you might want to read a
rebuttal page.
 
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