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Based on DVD's dual-layer and double-sided options, there are
four disc construction formats: Single-Sided, Single-Layered. Also known as DVD-5, this simplest construction format holds 4.7 Gigabytes (GBytes) of digital data. The "5" in "DVD-5" signifies the nearly 5 GBytes worth of data capacity. Compared to 650 Megabytes (MB) of data on CD, the basic DVD-5 has over seven times the data capacity of that of a CD. That's enough digital information for approximately two hours of digital video and audio for DVD-Video, or 74 minutes of high resolution music for DVD-Audio. Single-Sided, Dual-Layered. The DVD-9 construction holds about 8.5 GBytes. DVD-9s do not require manual flipping: the DVD player automatically switches to the second layer in a fraction of a second, by re-focusing the laser pickup on the deeper second layer. This capability allows for uninterrupted playback of long movies up to four hours! Frequently, DVD-9 is used to put a movie and its rich set of bonus materials on the same DVD-Video disc, or its optional DTS Surround Sound track. Double-Sided, Single-Layered. Known as DVD-10, this construction features a capacity of 9.4 GBytes of data. DVD-10s are commonly used to put a widescreen version of the movie on one side, and a full frame version of the same movie on the other side. Almost all DVD players require you to manually flip the DVD, that's why the DVD-10 is called the "flipper" disc. (There are a few DVD players that can perform the side flipping automatically.) Double-Sided, Dual-Layered. The DVD-18 construction can hold approximately 17 GBytes (almost 26 times the data capacity of a CD), or about 8 hours of video and audio as a DVD-Video. Think of DVD-18 as a double-sided DVD-9, where up to four hours of uninterrupted video and audio can be stored on one side. To access the content on the other side of a DVD-18, you have to manually flip the DVD. To date, few titles have been released using this construction. Content providers (e.g., movie studios) usually choose to go with two DVD-9s than a single DVD-18 because DVD-18s cost far more to produce. |
