Blu-ray And Friends

Blu-ray is here to stay, as seen by the increasing number of Blu-ray movie titles appearing every day and the falling prices for Blu-ray players and recorders. Why all the fuss, and exactly what is Blue-ray anyway? Read on.

Blu-ray, also called Blu-ray disc (BD), is the name of an optical disk format. Blue-ray differs from its cousins, CDs and DVDs, in several ways. The most important and useful difference is in the amount of data Blu-ray disks can hold: more than five times as much as DVDs and 35 times more than CDs. In terms of actual storage capacity, a Blu-ray disc can hold about 25 GB of data, whether it’s movie or picture, document, or backup files. By comparison, a DVD will hold upwards of 4.7 GB and a CD about 700 KB (0.7GB) worth of whatever. Dual layer versions of Blu-ray discs hold about 50 GB, but not all Blu-ray players can read the dual layered discs. Looking to the future, Pioneer has reported a disk in development using 20 layers, pushing the capacity to a staggering 500 GB.

Why do we need all this storage capacity? Movies have been one important impetus for the push for larger capacities. Since CDs only hold about one hour of movies or video in a lower resolution format, their usefulness for full length features is limited. DVDs will easily hold a full-length feature movie and occasionally two versions of shorter movies (such as full-screen and widescreen) of the same movie and include some bonus features such as "The Making Of . . .," scene selections and the like.

But, along came HDTV (high definition television), with the requirement for much larger storage capacities to accommodate the information needed for the widescreen format (aspect ratio 16:9) and the 1,000 line resolution (by comparison, "old-fashioned" TVs sport an almost square format and 480 lines of resolution). Since DVDs cannot hold even one full-length HDTV feature (except for the rare short movie), manufacturers saw the need for a larger capacity disk.

Two competing high capacity storage formats arose: HD disks and Blu-ray discs. HD Disks had a head start to market, but the capacity was only 12 to 15 GB, and this format had extremely limited support from only three or four manufacturers. Blu-ray discs eventually won the format competition, in large measure because of the support of Sony and dozens of other manufacturers.

Blu-ray 101 Let’s look at some of the nuts and bolts of Blu-ray and why it can do the high capacity stuff.

Discs, whether they are audio CD discs, movie DVDs or Blu-ray, all store data coded as "pits" or holes in a reflective surface on the non-label side of the disc. A finely focused beam of laser light reads these pits as a break in the reflectivity, resulting in a digital signal of "reflected beam or no reflected beam – the infamous "1"s or "0"s of digital language. CD and DVD discs players use a red laser beam for reading these pits, whereas Blu-ray discs use a blue laser beam for reading. The shorter wavelength of the blue laser allows the beam to be more finely focused into a tinier spot than the red laser. Hence, the pits can be made smaller and more pits can fit on a Blu-ray disc and thus allow a larger data capacity. The pits are laid out in a concentric track, and if a track could be straightened out would be several thousand kilometers long.

We’ve been referring to commercially produced discs, such as audio CDs, movie DVDs, computer program discs and the like, but the same technology holds true when it comes to burning a disc using your computer. The tighter beam of a Blu-ray disc burner, the blue laser beam, will record more data on a Blu-ray disc than on a CD or DVD. The laser beam literally burns a tiny hole in the reflective layer to form a pit.

A greater degree of engineering goes into a Blu-ray disc player or player/recorder because of the tighter tolerances needed for that tiny blue laser beam. This results in higher costs both for the players and recordable Blu-ray discs. Prices for both have been falling, fueling the demand, so look for Blu-ray to eventually replace the DVD format as the format of choice.

Because of the large installed base of DVD players and thousands of DVD movies now available, most new Blu-ray players will still be able to play your collection of DVD discs. The principle reason for upgrading your player to a Blu-ray disc player is HDTV. HD movies seen on an HDTV are incredibly sharp and have vivid colors. The extra Blu-ray disc capacity supports high definition audio formats and lossless audio. In addition, there is plenty of storage room for extra content and special features. Internet interactivity and overlay special features while the movie is running are some of the exciting new capabilities to look for.

Yes, Blu-ray is here to stay.