PTP stands for Parallel Track Path. This is a variation of DVD dual-layer disc layout where both layers are read as clockwise spirals from the center of the disc. This is often used with DVD-Video, where two different versions of a movie (like a 4:3 version and a 16:9 version) are stored on the same side of a DVD disc. It is also good for use with DVD-ROM.
See also: OTP
