DVD Formats Explained

DVD (Digital Versatile Disc or Digital Video Disc) refers to an optical media capable of storing 6 times the storage capacity of a regular compact discs (CDs). Laser light at 650 nm is used for reading and writing purposes.  The usage of shorter wavelength light is the reason for increased size, since smaller pits are created.  Blu-ray disc, another type of optical disc is the successor to the DVD optical media and uses 405 nm blue-violet laser light.  This article provides information about the types of DVDs available and their features. The difference in variation in names is due to the difference in way of storing data.
Optical storage media have come a long way. In the beginning there were only CD/DVD players and they were very expensive. A DVD writer could not be afforded by majority. Thanks to advancements in optical media technology, now data can be easily transferred and also the disc burners are very cheap. There are innumerable formats of DVDs available. Why are there so many formats? What is the reason for having so many formats? Are all the formats compatible with all the types of disc burners available?
The difference in the format is due to the fact that different manufacturers make use of different standards. There is intense competition between these companies with respect to the disc burners and optical media and they try to out beat the competitor and gain major market share. They try to add their own customization to the standard devices and try to make them advantageous over others. To gain supremacy, many features are added that might give upper hand in sales compared to other optical media.
The different types of DVDs are as follows

• DVD+R – These are recordable discs similar to CD-R and once data is written, it cannot be erased or changed. The data is permanently stored on the disc. Most of the companies like Sony, Hewlett Packard, Dell, Yamaha and many more companies support this format.
• DVD+RW – This type of discs can be rewritten or modified as many times. They are called re writable DVD discs. Of course, the number of times the data can be re-written is limited and the disc is prone to damage after excessive usage.
• DVD-R: These are DVDs that can be recorded only one time and once recorded; the data is permanent and cannot be changed or erased. There are two types available and they include DVD-RG and DVD-RA. DVD-RG is common recordable disc available for general use and DVD-RA are used for mastering. Hitachi, Smasung, Apple Panasonic and Toshiba are some of the companies that support this format. The “+” and “-“(DVD+R and DVD-R) just refer to physical format and way of data storing. There is no other difference.
• DVD-RW: This is similar to DVD+RW. Data can be burned on to the disc any number of time without damaging the disc.
• DVD–RAM: These discs are rewritable discs that can be burned and modified repeatedly, but they can be used with only disc burners that support it. They are encased in cartridges and are very expensive.
• DVD-ROM: This is the de facto standard that is similar to CD-ROM. These discs are read only and cannot be altered. Popular games DVDs are provided on this type of optical media.
• DVD+R DL – These are dual layer DVD recordable discs. They can hold more data compared to the single layer or ordinary DVDs. Double sided dual layer discs can hole approximately 16 GB of data. DVD-R DL is also similar to DVD+R DL. They are also called DVD+R9 or DVD-R9.
• DVD VCD – An ordinary disc in which the data is encoded to MPEG1 video format. DVD-SVCD refers to DVD that provides SVCD content. DVD discs do not support this format and these are non standard discs.
• DVD-D: these are discs that get damaged and cannot be read after 48 hours. These help to curb piracy and are provided as rental DVDs.
• HD-DVD is a DVD that can store large amount of data, about 2-3 times that data stored on regular DVD.

From 2003 onwards, multi format disc burners have been introduced that can burn and read any type of DVD format.  Therefore, consumers need not worry about the compatibility issues with their burners.