In 1997, a new technology emerged that brought digital sound and video into houses all end the world. That was called DVD, and also it reinvented the movie industry.

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The sector is collection for however another change with the arrival of Blu-ray Discs (BD) in 2006. Through their high storage capacity, Blu-ray discs deserve to hold and also play back big quantities of high-definition video and audio, and also photos, data and other digital content.

In this article, defines how the Blu-ray disc works and how it was developed, and also we"ll see exactly how it stacks up versus some other new digital video formats ~ above the horizon.

A current, single-sided, standard DVD have the right to hold 4.7 GB (gigabytes) of information. That"s about the dimension of an typical two-hour, standard-definition movie v a couple of extra features. However a high-definition movie, which has a much clearer image (see how Digital tv Works), take away up about five times more bandwidth and therefore calls for a bowl with around five times an ext storage. As TV sets and movie studios do the move to high definition, consumers room going to require playback systems with a lot more storage capacity.

Blu-ray discs not just have more storage capacity than timeless DVDs, yet they also offer a new level that interactivity. Users will have the ability to connect to the Internet and instantly download subtitles and other interactive movie features. With Blu-ray, girlfriend can:

instantly skip to any kind of spot on the discrecord one program while city hall another top top the disccreate playlistsedit or reorder programs videotaped on the discautomatically search for one empty space on the disc to protect against recording end a programaccess the net to download subtitles and also other extra features

Discs keep digitally encoded video clip and audio information in pits -- spiral grooves that run from the facility of the disc come its edges. A laser reads the other side of these pits -- the bump -- to play the movie or regimen that is save on the DVD. The an ext data the is included on a disc, the smaller sized and more closely packed the pits need to be. The smaller sized the pits (and therefore the bumps), the an ext precise the analysis laser have to be.

Unlike present DVDs, which use a red laser come read and write data, Blu-ray uses a blue laser (which is wherein the layout gets that is name). A blue laser has actually a shorter wavelength (405 nanometers) 보다 a red laser (650 nanometers). The smaller beam focuses more precisely, allowing it to read details recorded in pits the are only 0.15 microns (µm) (1 micron = 10-6 meters) lengthy -- this is more than double as little as the pits top top a DVD. Plus, Blu-ray has decreased the track pitch indigenous 0.74 microns come 0.32 microns. The smaller sized pits, smaller sized beam and much shorter track key together allow a single-layer Blu-ray disc come hold more than 25 GB of information -- about five times the lot of details that deserve to be save on a DVD.

Each Blu-ray bowl is about the same thickness (1.2 millimeters) as a DVD. However the two types of discs keep data differently. In a DVD, the data is sandwiched in between two polycarbonate layers, each 0.6-mm thick. Having a polycarbonate layer on top of the data can reason a difficulty called birefringence, in i beg your pardon the substrate great refracts the laser light right into two separate beams. If the beam is split too widely, the disc cannot be read. Also, if the DVD surface ar is not exactly flat, and is thus not specifically perpendicular come the beam, it have the right to lead to a difficulty known together disc tilt, in i beg your pardon the laser beam is distorted. Every one of these issues lead to a really involved production process.

Learn how Blu-ray overcomes this obstacles in the next section.

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The Blu-ray surname is a mix of "blue," because that the shade of the laser the is used, and "ray," because that optical ray. The "e" in "blue" was purposefully left off, according to the manufacturers, because an day-to-day word cannot be trademarked.