Blu-ray Disc aka BD is an optical storage media that is next-generation optical disc format jointly developed by the Blu-ray Disc Association (BDA), a group of the world's leading consumer electronics, personal computer and media manufacturers. Its main use is to store the high definition video. The main advantage of Blu-ray is the sheer amount of data storage.
- A single-layer Blu-ray disc, which is the same size of a standard DVD, can hold up to 27 GB of data.
- A double-layer Blu-ray disc can store up to 50 GB.
All current optical disc such as DVD rely on a red laser to read and write data, the new format as BD uses a blue-violet laser instead, hence the name Blu-ray. The benefit of using a blue-violet laser is that it can focus the laser spot with even greater precision which permits data to be packed more tightly and stored in less space, so data storage increases even though it's the same size as a CD/DVD. Apart from its storage capacity, it provides more interactivity to its users. With Blu-ray, you can:
- record high-definition television without any quality loss
- instantly skip to any spot on the disc
- record one program while watching another on the disc
- create play lists
- edit or reorder programs recorded on the disc
- automatically search for an empty space on the disc to avoid recording over a program
- access the Web to download subtitles and other extra features
Blu-ray discs store data in form of pits - spiral grooves that run from the center of the disc to its edges. The design of the Blu-ray discs saves on manufacturing costs. Blu-ray also has a higher data transfer rate -- 36 Mbps than DVD, which transfer at 10 Mbps. A Blu-ray disc can record 25 GB of material in just over an hour and a half. Technical specifications of Blu-ray Disc : Type : Standard disc size Phyical size : 12 cm, single sided Single Layer Capacity : 25 GB (23.28 GiB) Dual Layer Capacity : 50 GB (46.56 GiB) Type : Mini disc size Phyical size : 8 cm, single sided Single Layer Capacity : 7.8 GB (7.26 GiB) Dual Layer Capacity : 15.6 GB (14.53 GiB) Various variants of blu-ray Disc : Mini Blu-ray Disc : It is a compact 8cm (~3in) diameter variant of the Blu-ray Disc that can store approximately 7.5GB of data. BD9/BD5 Blu-ray Disc : BD9 and BD5 are lower capacity variants of the Blu-ray Disc that contain Blu-ray compatible video and audio streams contained on a conventional DVD optical disc. AVCREC : AVCREC is an official lower capacity variant of the Blu-ray Disc used for storing Blu-ray Disc compatible content on conventional DVD discs.