About DVDs


The Digital Versatile Disc is quite the wonder: it's physically small, like a CD, but packs nearly seven times the data into the same space: a CD stores roughly 700 MB, while a DVD holds approximately 4.7 GB. In addition to storing all this data, DVDs can be set up so they automatically play movie files and include a menu system to give you control over how the content plays.

DVD physical formats

Before you rush out and buy a mega-pack of blank DVDs, take a few minutes to acquaint yourself with the different formats that are out there.

  • DVD-R. DVD-Recordable discs can be burned once, and then played back in nearly any consumer DVD player and DVD-capable computer. When purchasing DVD-R media, be sure to get DVD-R (General); the other type, DVD-R (Authoring), is used in professional DVD writers and is not supported by iDVD. The discs Apple sells are DVD-R format.

  • DVD-RW. DVD-Rewritable discs can be erased and burned hundreds of times, which make them great for testing purposes (you can burn iterations of your project onto one DVD-RW disc, instead of making lots of DVD-R coasters).

  • DVD+R, DVD+RW. These two formats use a different method of recording data than DVD-R and DVD-RW. They don't offer more storage or features, and cost about the same as the -R and -RW discs.

  • DVD-ROM. DVD-Read-Only-Media discs cannot be burned because their data has already been written to disc. The iLife '06 installation disc is an example of DVD-ROM.

4x DVD Media Alert!

Before you burn any DVD disc, make sure your SuperDrive's firmware has been updated. All SuperDrives can burn 1x- and 2x-speed DVD-R media. When using 4x-speed media, however, some older mechanisms can not only fail to write the disc, but they can also be permanently damaged! Fixes are availablesee http://docs.info.apple.com/article.html?artnum=86130 for more information.


DVD Logical Structure

A blank DVD disc contains no information or directory structure. The way a DVD's data is stored on the disc depends on how the disc will be used.

  • DVD-Video. A DVD that contains just a movie (and its associated menus and extras) is in DVD-Video format. The folders and filenames are specific: a folder called VIDEO_TS stores all of the movie's video and audio files. iDVD typically creates DVD-Video discs.

  • DVD-ROM. When you store just data on the disc, without the need to play back automatically in DVD players, the disc is in DVD-ROM format. This is just like using a CD-ROM, only with more storage capacity. The Finder can create DVD-ROM discs, such as when you're backing up data.

  • Hybrid DVD. You can store a DVD-Video project on a disc that also contains DVD-ROM data, which makes the disc a Hybrid DVD. iDVD can create Hybrid DVDs.





iMovie HD 6 & iDVD 6 for Mac OS X (Visual QuickStart Guide Series)
iMovie HD 6 and iDVD 6 for Mac OS X
ISBN: 0321423275
EAN: 2147483647
Year: 2004
Pages: 197
Authors: Jeff Carlson

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