DVD+R

Two DVD+R discs, showing the factory label on the front face and the visible, foil layer on the reverse

A DVD+R is a recordable optical disc. It is similar to, but incompatible with, the older DVD-R standard. A DVD+R is a write-once optical disc with 4.7 gigabytes (GB) of storage, generally used for non-volatile data storage or video applications.

History

The DVD+R format was developed by a coalition of corporations—now known as the DVD+RW Alliance—in mid-2002 (though most of the initial advocacy was from Sony). The DVD+R format competes with the DVD-R format, which is developed by the DVD Forum. The DVD Forum initially did not approve of the DVD+R format and claimed that the DVD+R format was not an official DVD format until January 25, 2008.^[1]

In October 2003, it was demonstrated that double layer technology could be used with a DVD+R disc to nearly double the capacity to 8.5 GB per disc. Manufacturers have incorporated this technology into commercial devices since mid-2004.^{[citation needed]}

As of 2007, the recordable DVD market still shows little sign of settling down in favor of either format. Since almost all new^{[clarification needed]} DVD writers can record to both formats, this is not an issue for most people. When creating DVDs for distribution (where the playing unit is unknown or older), using the DVD-R format is preferable, because most older (up to 2004) standalone DVD video players and DVD ROM drives cannot read discs in the later DVD+R format.^[2]

On 25 January 2008, DVD6C officially accepted DVD+R and DVD+RW by adding them to its list of licensable DVD products.^[1]

Technical details

DVD+R discs carry up to 8.5 GB of data, approximately the same as DVD-R.^[3] Unlike DVD+RW discs, DVD+R discs can only be written to once. Because of this, DVD+R discs are suited to applications such as non-volatile data storage, audio, or video. This can cause confusion because the DVD+RW Alliance logo is a stylized 'RW'. Thus, a DVD+R disc may have the RW logo, but it is not rewritable.

DVD+R discs must be formatted before being recorded by a compatible DVD video recorder. DVD-R do not have to be formatted before being recorded by a compatible DVD video recorder. This is because the two variants of the discs are written in different formats (See DVD+VR and DVD-VR respectively).

The DVD+R format is divergent from the DVD-R format. Hybrid drives that can handle both, often labeled 'DVD±RW', are very popular since there is not a single standard for recordable DVDs. There are a number of significant technical differences between the 'dash' and the 'plus' format, although most users would not notice the difference. One example is that the DVD+R style Address In Pregroove (ADIP) system of tracking and speed control is less susceptible to interference and error, which makes the ADIP system more accurate at higher speeds than the Land Pre Pit (LPP) system used by DVD-R. In addition, DVD+R(W) has a more robust error management system than DVD-R(W), allowing for more accurate burning to media, independent of the quality of the media. The practical upshot is that a DVD+R writer is able to locate data on the disc to byte accuracy whereas DVD-R is incapable of such precision.

Additional session linking methods are more accurate with DVD+R(W) versus DVD-R(W), resulting in fewer damaged or unusable discs due to buffer under-run and multi-session discs with fewer PI/PO errors.^[4]

Like other 'plus' media, it is possible to change the book type to increase the compatibility of DVD+R media (though unlike DVD+RW, it is a one way process). This is also known as bitsetting.^[5]

Recordable DVD capacity comparison

For comparison, the table below shows storage capacities of the four most common DVD recordable media, excluding DVD-RAM. SL stands for standard single-layer discs, while DL denotes the double-layer variants. See articles on the formats in question for information on compatibility issues.

See also

• DVD
• DVD recorder (DVDR)
• DVD-R DL
• CD-R
• DVD+R DL
• DVD-RW
• DVD+RW
• DVD+RW DL
• DVD-RAM
• MiniDVD
• MultiLevel Recording, an obsolete technology (with non-binary modulation)
• Blu-ray Disc
• Blu-ray Disc recordable

References

1. ^ ^{a b} "DVD6C Announces New Licensing Program". Retrieved 2008-01-25. 
2. ^ "What is DVD?". Retrieved 2008-07-23. 
3. ^ "Understanding DVD". Optical Storage Technology Association. 2004. Retrieved 2008-09-06. 
4. ^ How To Choose CD/DVD Archival Media, Patrick McFarland, adterrasperaspera.com, October 30th, 2006
5. ^ "Increased compatibility: DVD bitsetting". Retrieved 2008-09-15. 

External links

• ISO/IEC 17344:2005, Data interchange on 120 mm and 80 mm Optical Disc using +R format - technical specification
• ISO/IEC 25434:2008, Data interchange on 120 mm and 80 mm optical disc using +R DL format -- Capacity: 8.55 GB and 2.66 GB per side (recording speed up to 16X) - technical specification
• Official white papers
• What's the difference between DVD-R and DVD+R? (DVD demystified)
• Why DVD+R(W) is superior to DVD-R(W) (opinion piece)