Optical disc authoring Optical disc authoring Optical disc authoring, including DVD and Blu-ray Disc authoring is the process of assembling source material—video, audio or other data—into the proper logical volume format to then be recorded ("burned") onto an optical disc (typically a compact disc or DVD). To burn an optical disc, one usually first creates an optical disc image with a full file system, of a type designed for the optical disc, in temporary storage such as a file in another file system on a disk drive. Then, one copies the image to the disc. Most optical disc authoring utilities create a disc
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