Introduction to DVD+RW
Arising from the need to store ever-larger amounts of data on an optical disc,
the pre-recorded DVD-Video (Digital Versatile Disc) can store 4.7 gigabyte of
information corresponding to more than two hours of high- quality 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 foreseeable capacity needs, it
is also well-suited to the operating needs of the latest multimedia PCs and CE
appliances using digitised audio, graphical and video information. Though
pre-recorded DVDs (DVD-ROM and DVD-Video discs) have been around for a while,
recordable and rewritable DVDs are a more recent but crucial development.
Already, several rewritable formats exist: DVD+RW, DVD-RW and DVD-RAM. Of
these, DVD+RW, developed in co-operation by Hewlett-Packard, Mitsubishi
Chemical, Philips, Ricoh, Sony and Yamaha, provides a breakthrough in DVD
technology: a rewritable format that provides full compatibility with existing
DVD-Video players and DVD-ROM drives. As consumer and IT applications for DVD
continue to converge, DVD+RW provides a disc format suitable for both
real-time video recording and random data recording - the best of both worlds
- in a system that also offers effective means to prevent unauthorised copying
of copyright-protected content.
DVD+RW Video format
The pre-recorded DVD-Video market is booming, and Philips believes that
DVD-Video will become the mainstream pre-recorded video distribution format.
Adding recording capabilities to DVD players 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 played on the same
equipment. This is one reason why DVD+RW is a major breakthrough in
rewritable DVD technology. Philips' DVD+ReWritable Video format, based on
the recently announced 4.7 GB DVD+RW storage technology, provides
compatibility with existing DVD-Video and DVD-ROM equipment, and allows
media interchange between consumer electronic equipment and PC platforms.
DVD+RW Physical format
DVD+RW is designed to be used for both data and video content across PC
and entertainment applications. DVD+RW recognises that these applications
are rapidly converging, and that content must be portable across various
types of equipment. DVD+RW has therefore been designed to be compatible with
existing DVD-ROM and DVD-Video formats. An important benefit for PC
applications is the capability of the DVD+RW format to allow 'CAV recording'
(Constant Angular Velocity). Due to the constant rotation speed of the disc
CAV recording 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 'losses linking' allowing to use variable bit rate recording
for longer playing times.
Two-way compatibility
DVD+RW Video technology provides a unique advantage: Recorded discs can be
played back on existing DVD- Video players. Recordings made with a DVD
Video Recorder on DVD+RW discs can be played on DVD Video players as well
as on PCs with a DVD-ROM drive and MPEG2 video decoding capability. DVD+RW
discs offer up to 4 hours record/playback 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 achieved, or the recording quality can be
further improved without reducing the recording time. DVD-Video playback
compatibility with real-time variable bit-rate recording is achieved by
using 'Lossless linking', a technique developed specifically for DVD+RW.
Simplified editing
Philips' DVD+RW Video technology also offers easy-to-use-editing
facilities. Whereas editing private camcorder material on conventional
equipment generally requires two video devices, random access to a DVD+RW
disc means editing can be done using a single DVD Video Recorder. This
brings editing within reach of the average 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 DVD Video market,
strengthening its long-term interest to both equipment manufacturers and
the movie industry alike.
DVD+RW at a glance
Listing of the main DVD+RW features:
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 CLV and CAV recording Write speeds from I x to 2.4x DVD-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 ECC 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 physical parameters comply with the DVD-ROM
specification.
Source:
Philips Intellectual Property & Standards |
