Blu-Ray

Blu-ray Disc (also called BD) is a high-density optical disc format for the storage of digital information, including high-definition video.

The name Blu-ray Disc is based from the blue-violet laser used to read and write this type of disc. Because of its shorter wavelength (405 nm),significantly more data can be stored on a Blu-ray Disc than on the DVD format, which uses a red (650 nm) laser. A single layer Blu-ray Disc can store 25 GB, over 5 times the size of a single layer DVD at 4.7 GB. A dual layer Blu-ray Disc can store 50 GB, almost 6 times the size of a dual layer DVD at 8.5 GB.Blu-ray Disc is currently in a formal war with rival format HD DVD.

Recording 18 hours of 1080p on a single disc is pretty serious stuff, and Panasonic Blu-ray recorders launched at CEATEC Japan do this. They do this via a digital TV tuner, and MPEG 4 compression, and support for 50GB dual layer discs you'd see on a PC recorder, but never before on a home theater box. The players also have HDDs in them, up to $2600 for a 1TB model (There are 5 other lesser models, too, and the phrase product spam (comes to mind). The terrabyte drive can do 381 hours of recording, but using that lowest setting for 1080p seems perverse and wrong. Transferring from HDD to disc can be done at 4x. Japan only, for now, and given the high-endness of this setup and American HDMI DRM, maybe forever. [PC World]