DVD recordable
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It has been suggested that this article be merged with DVD-R, DVD+R, DVD-RW and DVD+RW. (Discuss) Proposed since April 2013. |
DVD recordable and DVD rewritable refer to part of Optical disc recording technologies. DVD optical disc formats that can be recorded by a DVD recorder, (written, "burned"), either write once or rewritable (write multiple times) format written by laser, as compared to DVD-ROM, which is mass-produced by pressing, primarily for the distribution of home video. DVD recordable is a general term that refers to both write-once and rewritable formats, whereas DVD rewritable refers only to rewritable formats.
Like CD-Rs, DVD recordables use dyes. Depending on the intensity of the laser, the reflective property of the dye on a particular spot will determine whether it is a peak or a valley representation from pressed DVD. Dyes give the data side of a disc a distinct color. Dyes are also the reason playback is not guaranteed. Their reflective properties are not as good as with stamped DVDs that commonly have aluminum as the reflective layer.
Recordable DVDs are divided into three incompatible camps:
- DVD-R/DVD-RW (DVD "minus" or DVD "dash")
- First DVD recordable format released in the market. Developed by Pioneer and backed by the DVD Forum. Has broader playback compatibility than the "+" especially with much older players. The dash format is based on an older CD-R/RW format for easy upgrade or migration for disc manufacturers[citation needed] and uses a "pre-pit" method [1] to provide 'sector' address information (as does CD-R).
- DVD+R/DVD+RW (DVD "plus")
- Developed by Philips and Sony with their DVD+RW Alliance. The "plus" format uses a more reliable phase modulation technique [2] to provide 'sector' address information. Introduced after the "-" format.
- DVD-RAM
- As RAM stands for Random Access Memory, it works more or less like a hard-drive and was designed for corporate back-up use. Can only be read in drives that are DVD-RAM compatible. DVD Forum backs this format.
Michael Spath at CDfreaks analyzed the specifications of DVD-R/RW and DVD+R/RW formats and came to the conclusion that the DVD+R/RW format is superior to DVD-R/RW.[3]
Multi-format drives can read and write more than one format; e.g., DVD±RW (DVD plus-dash rewritable) is used to refer to drives that can write/rewrite both plus and dash formats, but not necessarily DVD-RAM.
DVD recordable media are sold in two standard sizes, a standard-sized 12cm size for home recording and computer usage, and a small 8cm size (sometimes known as a miniDVD) for use in compact camcorders and the like.
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DVD write-once formats [edit]
DVD rewritable formats [edit]
Speed [edit]
| Drive speed | Data rate | Disc write time | Equivalent CD rate | Reading speed | |
|---|---|---|---|---|---|
| 1× | 11.08 Mbit/s | 1.385 MB/s | 53 min | 9× | 8×–18× |
| 2× | 22.16 Mbit/s | 2.770 MB/s | 27 min | 18× | 20×–24× |
| 4× | 44.32 Mbit/s | 5.540 MB/s | 14 min | 36× | 24×–32× |
| 5× | 55.40 Mbit/s | 6.925 MB/s | 11 min | 45× | 24×–32× |
| 6× | 66.48 Mbit/s | 8.310 MB/s | 9 min | 54× | 24×–32× |
| 8× | 88.64 Mbit/s | 11.080 MB/s | 7 min | 72× | 32×–40× |
| 10× | 110.80 Mbit/s | 13.850 MB/s | 6 min | 90× | 32×–40× |
| 16× | 177.28 Mbit/s | 22.160 MB/s | 4 min | 144× | 32×–40× |
| 18× | 199.44 Mbit/s | 24.930 MB/s | 3 min | 162× | 32×–40× |
| 20× | 221.60 Mbit/s | 27.700 MB/s | 2 min | 180x | 32×–40× |
| 24× | 265.92 Mbit/s | 33.240 MB/s | 2 min | 216x | 32×–48× |
Notes:
- DVD 1× actual spin is 3 times that of CD 1×
- Disk write time in table does not include overhead, leadout, etc.
Capacities [edit]
- See also: DVD#Capacity
Most DVD±R/RWs are advertised as having a capacity of 4.7 GB. However these DVDs seem to hold less than the stated 4.7GB because many manufacturers quote the capacity of a DVD using decimal prefixes instead of the binary prefixes often used by software. This can be confusing for many users. While a 4.7 GB DVD can store 4.7 billion bytes: 4,700,000,000 bytes ÷ 1000 B/kB = 4,700,000 kB ÷ 1000 kB/MB = 4,700 MB ÷ 1000 MB/GB = 4.7 GB, using binary prefixes the same capacity is roughly 4.38 GiB: 4,700,000,000 bytes ÷ 1024 B/KiB = 4,589,844 KiB ÷ 1024 KiB/MiB = 4,482.27 MiB ÷ 1024 MiB/GiB = 4.38 GiB.[4]
| Format | Decimal Prefix | Binary Prefix |
|---|---|---|
| DVD±R | 4.70GB | 4.38GiB |
| DVD±RW | 4.70GB | 4.38GiB |
| DVD±R DL | 8.55GB | 7.96GiB |
| DVD-RAM | 4.70GB | 4.27GiB |
| DVD-RAM DL | 9.4GB | 8.75GiB |
| MiniDVD | 1.46GB | 1.36GiB |
| MiniDVD DL | 2.66GB | 2.48GiB |
Longevity [edit]
According to a study published in 2008 by the Preservation Research and Testing Division of the U.S. Library of Congress, most recordable CD products have a higher probability of greater longevity compared to recordable DVD products.[5]
References [edit]
- ^ "ECMA standard 279". Retrieved 2013-01-29.
- ^ "ECMA standard 349". Retrieved 2013-01-29.
- ^ "Why DVD+R(W) is superior to DVD-R(W)". Retrieved 2010-03-14.
- ^ osta.org
- ^ CD-R and DVD-R RW Longevity Research