Blu-ray is a cutting-edge, high-definition optical disc that can store
significantly more data than a standard DVD. A single-layer Blu-ray disc can
store approximately 25 gigabytes of data: five times the amount of a standard
single-layer DVD. Dual-layer Blu-ray discs can store twice the amount as
single-layer discs, and about eight times the amount of a standard dual-layer
DVD.
A standard DVD contains enough space for a two-hour, non-high-definition movie, plus a few extra features. A Blu-ray disc allows enough space for 13 hours of standard footage or two hours of high-definition video. In addition, Blu-ray discs allow you to skip instantly anywhere on the disc; record one show while watching another; edit and reorder the footage on the disc; and access the web to download subtitles and other extras.
All DVD's and CD's store information as a series of grooves on the recording surface of the disc. The grooves are written in a spiral that winds from the center of the disc to the outside edge. On one side, the grooves appear as pits; on the other, they stand out as bumps. To read the disc, a player shines a laser over the bumpy side of the disc. The bumps cause the laser to bounce back and register on a sensor.
Standard CD and DVD players use a red laser to read the information on a disc. Blu-ray compatible players use a blue laser. Blue light has a shorter wavelength than red light. This makes the laser itself more sensitive and capable of detecting much smaller grooves than a red laser can.
Because the blue laser can detect smaller grooves, the information on a Blu-ray disc can be written much smaller than on a standard disc. This is why a Blu-ray disc can contain so much more information than a standard CD or DVD, even though the discs are the same size.
Blu-ray discs are constructed differently than standard discs. These differences in construction eliminate some of the design flaws in standard DVD's. One of these flaws is birefringence. In a standard DVD, the recorded data is set between two polycarbonate layers. The laser must shine through a layer of polycarbonate in order to reach the data.
Occasionally, the polycarbonate can split the laser into two beams instead of allowing it to penetrate, making the player unable to read the disc. The process of lining up the polycarbonate layers must be done with great precision to prevent birefringence. In addition, the laser beam can become distorted if the disc is not perfectly level inside the player, a problem called "disc tilt."
Read more....
A standard DVD contains enough space for a two-hour, non-high-definition movie, plus a few extra features. A Blu-ray disc allows enough space for 13 hours of standard footage or two hours of high-definition video. In addition, Blu-ray discs allow you to skip instantly anywhere on the disc; record one show while watching another; edit and reorder the footage on the disc; and access the web to download subtitles and other extras.
All DVD's and CD's store information as a series of grooves on the recording surface of the disc. The grooves are written in a spiral that winds from the center of the disc to the outside edge. On one side, the grooves appear as pits; on the other, they stand out as bumps. To read the disc, a player shines a laser over the bumpy side of the disc. The bumps cause the laser to bounce back and register on a sensor.
Standard CD and DVD players use a red laser to read the information on a disc. Blu-ray compatible players use a blue laser. Blue light has a shorter wavelength than red light. This makes the laser itself more sensitive and capable of detecting much smaller grooves than a red laser can.
Because the blue laser can detect smaller grooves, the information on a Blu-ray disc can be written much smaller than on a standard disc. This is why a Blu-ray disc can contain so much more information than a standard CD or DVD, even though the discs are the same size.
Blu-ray discs are constructed differently than standard discs. These differences in construction eliminate some of the design flaws in standard DVD's. One of these flaws is birefringence. In a standard DVD, the recorded data is set between two polycarbonate layers. The laser must shine through a layer of polycarbonate in order to reach the data.
Occasionally, the polycarbonate can split the laser into two beams instead of allowing it to penetrate, making the player unable to read the disc. The process of lining up the polycarbonate layers must be done with great precision to prevent birefringence. In addition, the laser beam can become distorted if the disc is not perfectly level inside the player, a problem called "disc tilt."
Read more....
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