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DVD+ReWritable technology
DVD+ReW ritable
Ho w it works
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DVD+ReWritable technology
D VD+ReWritab le and ho w it works
Introduction
Arising from the need to store ev er -larger amounts of data on an optical disc,the pre-recorded D VD-Video
(Digital V ersatile Disc) can store 4.7 gigab yte of information corresponding to mor e than two hours of highquality digital video on a single-sided (CD-size) 12 cm disc.The high-density successor to the popular CD media
family ,DVD not only meets f oreseeable capacity needs,it is also well-suited to the operating needs of the latest
multimedia PCs and CE appliances using digitized audio,graphical and video information.
Though pre-recorded D VDs (D VD-R OM and D VD-Video discs) ha ve been around f or a while,recordable and
rewritable D VDs are a mor e recent but crucial dev elopment.Already ,several re writable formats exist:
DVD+RW ,D VD-R W and D VD-RAM.Of these,DVD+R W,developed in co-operation by He wlett-Packard,
Mitsubishi Chemical,Philips,Ricoh,Sony and Yamaha,provides a breakthrough in D VD technology:it is the only
rewritable format that pr ovides full compatibility with existing D VD-Video play ers and D VD-R OM drives.
As consumer and IT applications for D VD continue to converge,DVD+RW provides a disc format suitable for
both real-time video recording and random data r ecording – the best of both worlds – in a system that also
offers effective means to pre vent unauthorized cop ying of copyright-pr otected content.
D VD+R W:Physical format
DVD+R W is designed to be used for both data and video content acr oss PC and entertainment applications.
DVD+R W r ecognizes that these applications are rapidly conv erging,and that content must be portable across
various types of equipment.DVD+R W has theref ore been designed to be compatible with existing D VD-ROM and
DVD-Video formats.
An important benefit for PC applications is the capability of the DVD+RW format to allow ‘CA V r ecording’
(Constant Angular V elocity).Due to the constant rotation speed of the disc CAV r ecording allows for fast
random access.Yet two other benefits are the incorporation of ‘Defect management’,especially designed for
reliability of the data,and ‘Quick formatting’,enabling instant use of blank discs. Above-mentioned benefits
support the use of the format in data systems requiring high performance.For video applications the format has
the capability of ‘lossless linking’ allowing to use variable bit rate r ecording for longer pla ying times.
DVD+R W at a glance
- Single-sided disc with 4.7 GB capacity
- Double-sided disc with 9.4 GB capacity
- Uses a bare disc - no cartridge required
- 650 nm laser (numerical aperture 0.65)
- Constant linear data density
- CL V and CA V recor ding
-Write speeds from 1x to 2.4x D VD-Video data rates
- Defect management handled by the drive
- Quick formatting
- Uses same 8-16 Modulation and RS code as DVD-ROM
- Recording
- Sequential and random recording
- 32 kB ERCO blocks
- Lossless linking
- Address information:
- Spiral groove with radial wobble (32T period)
- Phase modulation addresses
- Four addresses per ECC block of 32 kB
After recording all ph ysical parameters comply with the D VD-R OM specification.
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DVD+RW Video format
The pre-recorded D VD-Video mark et is booming,and Philips believes that D VD-Video will become the
mainstream pre-recor ded video distribution format.Adding recording capabilities to D VD pla yers will further
boost the appeal of the DVD system.Of course,for long-term success it is essential that both home-recorded
and pre-recorded discs can be pla yed on the same equipment.This is one r eason why D VD+RW is a major
breakthrough in re writable D VD technology .
Philips’ DVD+ReWritable Video format,based on the recently announced 4.7 GB DVD+R W storage technology ,
provides compatibility with existing D VD-Video and D VD-R OM equipment,and allows media interchange
between consumer electronic equipment and PC platforms.Moreov er ,DVD+R W offers the possibility to
combine digital video and digital data in a single file system as required for multimedia r ecording applications.
T wo-way compatibility
DVD+RW Video technology provides a unique advantage:Recorded discs can be played back on existing D VDVideo players.
Recordings made with a DVD Video Recorder on DVD+RW discs can be played on D VD Video players as well as
on PCs with a DVD-R OM driv e and MPEG2 video decoding capability .D VD+R W discs offer up to 4 hours
record/pla yback time per side,resulting in recording capacities of up to 8 hours for double-sided discs.
High-quality video at extended recording times
DVD+RW Video is encoded in MPEG2 with variable bit-rate,providing high bit-rates where necessary while no
storage capacity is wasted in scenes with less dynamic video.This means that with the same disc capacity much
longer recording times can be achiev ed,or the recording quality can be further improved without r educing the
recording time.DVD-Video pla yback compatibility with real-time variable bit-rate recor ding is achieved by using
‘Lossless linking’,a technique developed specifically for D VD+R W.
Simplified editing
Philips’ DVD+RW Video technology also offers easy-to-use editing facilities.Whereas editing private camcorder
material on conventional equipment generally requir es two video devices,random access to a DVD+R W disc
means editing can be done using a single DVD Video Recorder .This brings editing within reach of the a verage
consumer and makes it quick and very easy to use.Because of its PC-compatibility,advanced editing of
DVD+RW Video can be done on a PC.
With the addition of DVD+RW to the DVD media family,consumers get the best of both worlds – pre-recorded
high-quality recordings,plus home-recording capability.Without doubt,rewritable DVD will stimulate further
growth of the D VD Video market,strengthening its long-term interest to both equipment manufacturers and the
movie industry alike.
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