DVD player the Blu-ray Disc player, utilizing two incompatible technologies that reproduce higher quality video images than standard DVD. On February 19, 2008, Toshiba, creator of the former technology announced it would cease production on all HD DVD products leaving Blu-ray as the high definition successor to DVD players. Also, upscaling and up-converting DVD units are available that connect to televisions via a high definition interface and increase the overall picture quality. DVD player A DVD player is a device that plays DVD discs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. Some DVD players will
Optical medium Optical medium An optical medium is material through which electromagnetic waves propagate. It is a form of transmission medium. The permittivity and permeability of the medium define how electromagnetic waves propagate in it. The medium has an "intrinsic impedance", given by where formula_2 and formula_3 are the electric field and magnetic field, respectively. In a region with no electrical conductivity, the expression simplifies to: For example, in free space the intrinsic impedance is called the characteristic impedance of vacuum, denoted "Z", and Waves propagate through a medium with velocity formula_6, where formula_7 is the frequency and formula_8 is the wavelength