DVD-R: Basic things about format
DVD-R is a DVD recordable format. A DVD-R type has a storage capacity of 4.71 GB (or 4.38 GiB), although the capacity of the original standard developed by Pioneer was 3.95 GB (3.68 GiB). Both values are significantly larger than the storage capacity of its optical predecessor, the 700 MB CD-R – a DVD-R has 6.4 times the capacity of a CD-R. Pioneer has also developed an 8.54 GB DVD DVD dual layer version, DVD-R DL, and newcomer to market Blu ray dvd blank media
Data on a DVD-R cannot be changed, whereas a DVD-RW (DVD-rewritable) can be rewritten multiple (1000+) times. DVD-R(W) is one of three competing industry standard DVD recordable formats; the others are DVD+R(W) and DVD-RAM.
DVD+R discs have 4.7 GB or 4.377 GiB (DVD-R has 4.382 GiB) of storage capacity (more precisely, 2295104 sectors of 2048 bytes each. 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 nonvolatile data storage, audio, or video. This can cause confusion because the DVD+RW Alliance logo is a stylized “RW”. Thus, a DVD+R disc can have the RW logo, but it is not rewritable.
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” (it’s not a minus symbol) and the “plus” format, although most users would not notice the difference. One example is the DVD+R style ADIP (ADdress In Pregroove) system of tracking and speed control being less susceptible to interference and error which makes the ADIP system more accurate at higher speeds than the LPP (Land Pre Pit) 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. 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 disks with fewer PI/PO errors.
Like other “plus” media, it is possible to change the book type to increase the compatibility of DVD+R media. This is also known as bitsetting.
