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DVD-R and DVD+R
DVD-R, like the CD-R, offer write-once
recording with a capacity of 4.7GB per side |
The two write-once formats include DVD-R, from the DVD Forum, and
DVD+R, which is not supported by the DVD Forum.
DVD-R
DVD-R discs make use of a similar technology to CD-Rs but with a different dye
and smaller geometries. The first version of this format had a
capacity of 3.95GB but this has been increased to 4.7GB per
side.
There are two types of DVD-R disc ver 2.0 both with a capacity of
4.7GB.
- General purpose discs are intended for use by consumers but
do not allow any data to be written to the lead-in area. This means
that, for example, CSS copy protection cannot be used, but provision
is made for adding CPRM copy protection.
- Authoring use discs which are intended to be used by
authoring studios to test titles and also as media for glass
mastering.
The two diferent types require two different recorders and
media. One recorder can only write one type of media.
| Parameter |
Ver 1.0 |
Authoring
use |
General
use |
| Number of Sides |
1 or 2 |
1 or 2 |
|
| Capacity (GB) |
3.95 |
4.7 |
4.7 |
| Recording method |
Organic dye layer |
| Laser wavelength |
635/650nm |
635nm |
650nm |
| Min pit length (microns) |
0.44 |
0.40 |
0.40 |
| Track pitch (microns) |
0.80 |
0.74 |
0.74 |
| Laser wavelength |
635/650nm |
635nm |
650nm |
| Pre-pit addressing |
increment |
increment |
decrement |
| Serialisation for CPRM |
|
No |
Yes |
| Pre-recording |
|
No |
Yes |
| Track format |
Wobble pre-groove |
| Modulation & error correction |
8 to 16 & RSPC |
DVD-R is compatible with DVD-ROM, DVD-Video and
DVD-Audio so that recorded DVD-R discs can be read on any suitable DVD hardware, depending
on the format of the data contained on the DVD-R. However discs
cannot use CSS copy protection. Also DVD-9 discs cannot be written
to DVD-R.
DVD-R discs comprise the following data areas:
- Power Calibration Area (PCA)
- Recording Management Area (RMA)
- Lead-in Area
- Data Recordable Area
- Lead-out Area
DVD-R discs allow incremental writing (cf CD-R multisession
writing). Two types of incremental writing are defined:
- Type 1 allows DVD-R discs to be read by an ISO 9660 system,
and uses the UDF Bridge file system.
- Type 2 is for drag and drop file transfer and uses UDF
without ISO 9660.
For both types each section of data written to the disc is
a Bordered Area and is followed by the Border Out and Border In which precedes the next
Bordered Area (if any). Each Bordered Area begins with the UDF file system and ends
with the Virtual Allocation Table (VAT).
Media and drives are capable of up to 4x writing speed, and faster
speeds will be available in the future.
DVD+R
DVD+R discs should be called +R as they are not recognised by the DVD
Forum. This format, which is essentially very similar to DVD-R,
was developed by Philips and Sony. It is an extension of the
DVD+RW format supported by the DVD+RW Alliance comprising HP, Philips,
Ricoh, Sony, Yamaha, Verbatim/Mitsubishi Chemical, Dell and Thomson.
This format is similar in functionality and compatibility to DVD-R
General media and is intended for widespread playback on DVD-ROM drives
and DVD-Video players. DVD+R drives write at up to 4X speed and provide
a reliable, low-cost storage solution for archiving video, audio, images
and other data.
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