dvd4-7gb3.
dvd4-7gb3.qxd 3/4/00 12:11 pm Page 2 DVD+ReWritable technology DVD+ReWritable and how it works Introduction 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 highquality digital video on a single-sided (CD-size) 12 cm disc.
dvd4-7gb3.qxd 3/4/00 12:11 pm Page 3 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.
dvd4-7gb3.qxd 3/4/00 12:11 pm Page 4 DVD+ReWritable technology DVD+ReWritable and how it works DVD+RW: PC applications and file handling With the growing trend towards multimedia documents, which require large amounts of disc space, DVD+RW offers the ability to easily create, share, store and access such content-rich documents using a single disc.
dvd4-7gb3.qxd 3/4/00 Figure 1. 12:11 pm Page 5 Creating amorphous regions Creating polycrystalline regions temp temp o ~600 C melting point o ~600 C melting point tcooling o crystallisation temperature ~200 C tpass o ~200 C time tcrystal Figure 2.
dvd4-7gb3.qxd 3/4/00 12:11 pm Page 6 DVD+ReWritable technology DVD+ReWritable and how it works Plaser output (mW) Figure 3 Fig. 3. During recording, the laser output is modulated using three power levels; Pwrite, Perase and Pbias, according to a predefined write strategy.The laser in a DVD+RW system has to be pulsed (for thermal reasons) to form well-defined amorphous regions of the desired length (see Fig. 1).The power level Perase is used to form the crystalline regions between amorphous marks.
dvd4-7gb3.qxd 3/4/00 12:11 pm Page 7 DVD+RW: Lossless linking In the DVD+RW Video format, video can be encoded with a variable bit-rate (VBR). Because the writing process takes place at a constant bit rate, the writing process needs to be suspended and continued frequently. Normally, this would result in a linking loss, making the disc incompatible with read-only devices like DVD Video players and DVD-ROM drives.With DVD+RW it is possible to perform lossless linking, i.e.
dvd4-7gb3.qxd 3/4/00 12:11 pm Page 8 DVD+ReWritable technology DVD+ReWritable and how it works Philips Disc Systems Building SFF7 P.O.Box 80002 5600 JB Eindhoven The Netherlands Philips Media Relations Jeannet Harpe Building SFF-6 P.O.
