The three application formats of DVD include DVD-Video, DVD-Audio, and DVD-ROM. The DVD-Video format (commonly called “DVD”) is by far the most widely known. DVDVideo is principally a video and audio format used for movies, music concert videos, and other video-based programming.

It was developed with significant input from Hollywood studios and is intended to be a long-term replacement for the VHS videocassette as a means for delivering films into the home. DVD-Video discs are played in a machine that looks like a CD player connected to a TV set.

This format first emerged in the spring of 1997 and is now considered mainstream, having passed the 10% milestone adoption rate in North America by late 2000.

The DVD-Audio format features high-resolution, two-channel stereo and multi-channel (up to six discrete channels) audio. The format made its debut in the summer of 2000 after copy protection issues were resolved.

DVD-Audio titles are still very few in number and have not reached mainstream status, even though DVD-Audio and DVD-Video players are widely available. This is due primarily to the existence of several competing audio formats in the market.

DVD-ROM is a data storage format developed with significant input from the computer industry. It may be viewed as a fast, large-capacity CD-ROM. It is played back in a computer’s DVD-ROM drive. It allows for data archival and mass storage as well as interactive and/or web-based content. DVD-ROM is a superset of DVD-Video.

If implemented according to the specifications, DVD-Video discs will play with all the features in a DVD ROM drive, but DVD-ROM discs will not play in a DVD-Video player. (No harm will occur. The discs will either not play, or will only play the video portions of the DVD-ROM disc.) The DVD-ROM specification includes recordable versions - either one time (DVD-R), or many times (DVD-RAM).

At the introduction of DVD in early 1997 it was predicted that DVD-ROM would be more successful than DVD-Video. However, by mid-1998 there were more DVD-Video players being sold and more DVD Video titles are available than DVD-ROM. DVD-ROM as implemented so far has been an unstable device, difficult to install as an add-on and not always able to play all DVD-Video titles without glitches. It seems to be awaiting the legendary “killer application.”

Few DVD-ROM titles are available and most of those are simply CD-ROM titles that previously required multiple discs (e.g., telephone books, encyclopedias, large games).

A DVD disc may contain any combination of DVD-Video, DVD-Audio, and/or DVD-ROM applications. For example, some DVD movie titles contain DVD-ROM content portion on the same disc as the movie. This DVD-ROM content provides additional interactive and web-based content that can be accessed when using a computer with a DVD-ROM drive.

And some DVD-Audio titles are actually DVD-Audio/Video discs that have additional DVD-Video content. This content can provide video-based bonus programming such as artist interviews, music videos, or a Dolby Digital and/or DTS surround soundtrack. The soundtrack can be played back by any DVD Video player in conjunction with a 5.1-channel surround sound home theater system.

The DVD specification also includes these recordable formats:
■ DVD-R – DVD-R can record data once, and only in sequential order. It is compatible with all DVD drives and players. The capacity is 4.7 GB.
■ DVD-RW – The rewritable/erasable version of DVD-R. It is compatible with all DVD drives and players.
■ DVD+R and DVD+RW – The rewritable/erasable version of DVD+R.
■ DVD-RAM – Rewritable/erasable by definition.

The last three erasable (or rewritable) DVD formats—DVD-RW, DVD-RAM, and DVD+RW—are slightly different. Their differences have created mutual incompatibility issues and have led to competition among the standards.

That is, one recordable format cannot be used interchangeably with the other two recordable formats. And one of these recordable formats is not even compatible with most of the 17 million existing DVD-Video players.

This three-way format war is similar to the VHS vs. Betamax videocassette format war of the early 1980s. This incompatibility along with the high cost of owning a DVD recordable drive has limited the success of the DVD recordable market.

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