DVD formats

When you own a DVD player or a portable DVD player, you have to handle a dilemma situation: which DVD formats are proper for your device. Because their world is divided and when given a choice to buy, you should be ready to make the best choice.

There are many classifications of DVD (a DVD disk has 120 mm in diameter and 1.2 mm thick). According to the type of data there are:

  1. DVD-ROM, a high-capacity data storage medium
  2. DVD-Video, digital storage medium for feature-length motion pictures
  3. DVD-Audio which is a storage format similar to CD, for audio only
  4. DVD-RAM was the first rewritable (erasable) DVD on the market and has subsequently found competition in the DVD-RW and DVD+RW format.

According to the storage capacity there are:

  1. DVD-5, single-sided, single-layered disk with capacity up to 4.7 GB
  2. DVD-9, a single-sided, double-layered, capacity up to 8.5 GB
  3. DVD-10, a double-sided, single-layered disk, 9.4 GB
  4. DVD-18, a dual-sided, double-layered, 17 GB.

A third classification concerns the way of addressing( or reading), that is the determination of location of the laser beam on the disk. As the two types it contains are incompatible, you need to know what format is suitable for your DVD player. The two DVD formats are:

  • DVD-, the addressing is done with special marks along the groove.
  • DVD+, the addressing is done by changing the oscillating frequency.

A forth classification of DVD formats refers to how many times they can be recorded. There are two DVD formats:

  • DVD-R / DVD+R, that is DVD Recordable and can be recorded once only. There are two additional standards for DVD-R disks: DVD-RG for general use, and DVD-RA for authoring.
  • DVD-RW / DVD+RW, that is DVD Re-writable; these disks can be written and erased, making it possible to record them up to about a thousand times.
After being recorded, these DVDs are commonly used on DVD players and portable DVD players.

DVD formats are shown in the following table:

DVD Disc Format Type of DVD Unit
DVD Player DVD-R(G) DVD-R(A) DVD-RAM DVD-RW DVD+RW
R W R W R W R W R W R W
DVD-ROM Yes No Yes No Yes No Yes No Yes No Yes No
DVD-R(G) Yes No Yes Yes Yes No Yes No Yes Yes Yes No
DVD-R(A) Yes No Yes No Yes Yes Yes No Yes No Yes No
DVD-RAM No No No No No No Yes Yes No No No No
DVD-RW Yes No Yes Yes Yes No Yes No Yes Yes Yes No
DVD+RW Yes No Yes Yes Yes No No No Yes No Yes Yes
CD-R No No No No No No Yes No Yes Yes Yes Yes
CD-RW No No No No No No Yes No Yes Yes Yes Yes

The fifth classification refers to the technology used in the manufacturing process. The following two formats are to be developed in the future:

  • Blu-ray, developed by Sony and a group of partners
  • HD-DVD, using technology supplied by Toshiba and NEC (Toshiba DVD player and others who adhered to their technology).

Format Current generation Next generation
DVD
playback		 4.7GB (single-layer disc);
650nm red laser;
MPEG-2 video compression.		 HD-DVD disc;
9GB (dual layer disc);
650nm red laser;
MPEG-4 or improved MPEG-2 with extensive pre- and post-processing.
DVD
recordable		 4.7GB (single-layer disc);
DVD-R (write-once);
DVD-RAM (rewritable);
DVD-RW (rewritable);
DVD+RW (rewritable);
650nm red laser;
MPEG-2 video compression.		 Blu-ray disc;
27GB (single-layer disc);
up to 50GB (dual-layer disc);
450nm blue-violet laser;
MPEG-2 video.

The end of a war

There is a strong competition among DVD player producers, since there are two incompatible DVD formats on the market. This split of the DVD format and, therefore, of the DVD players, is not favorable for consumers. Fortunately, there is already a dual format recorder which is able to support both DVD-R(W) and DVD+R(W) disks. Nevertheless, it is argued that the incompatible DVD formats will still stay on the market for a while.