Picture-in-picture the screen. Televisions at the time were still analog format, and earlier versions of the PiP implemented in analog were too costly. New digital technology allowed the second video signal to be digitized and saved in a digital memory chip then replayed in a mini version. While the new technology was not good enough for color or full-screen viewing, it did provide a low-cost PiP feature. The Blu-ray Disc and HD DVD specifications included picture in picture, allowing viewers to see, say, the director's comment on a film they are watching. All of the Blu-ray Disc titles in 2006 and
Optical disc authoring require writing the entire disc at once, but allow writing of different parts at different times. This allows a user to construct a disc incrementally, as it could be on a rewritable medium like a floppy disk or rewritable CD. However, if the disc is non-rewritable, a given bit can be written only once. Due to this limitation, a non-rewritable disc whose burn failed for any reason cannot be repaired. (Such a disc is colloquially termed a "coaster", a reference to a beverage coaster.) There are many optical disc authoring technologies for optimizing the authoring process and preventing errors. Some