No such hard coating is
placed on the DVD.
A DVD suffers from Disc
A DVD player cannot play
A Hard coating is placed
outside to protect the BD
from scratches or
A BD doesn’t suffer from
A BD player can play a
DVD or a CD.
The name “Blu-Ray” is a combination of “Blue” and
“Ray” where Blue stands for the colour of the laser
that is used and “Ray” stands for the optical ray.
The “e” in “blue” was purposely left out because
according to the manufacturers, an everyday word
cannot be a trademark.
THE BLU-RAY DISCS COMES IN 4 DIFFERENT FORMATS.
1. BD-ROM (read only) – For reading recorded content.
2. BD-R (recordable) – For PC data storage.
3. BD-RW (rewritable) – For PC data storage.
4. BD-RE (rewritable) - For HDTV(high definition television) recording.
Single Layer BD
This type of BD’s can hold up to 25/27 GB . That
means 2 hours of HD video or about 13 hours of
Double Layer BD
This type of BD can hold data up to 50 GB. That
means 4.5 hours of HD video or about 20 hours of
The BD was developed by Blu-Ray association (which includes Apple,
Hitachi, HP, LG, Panasonic, Pioneer, Philips, Samsung, Sharp and Sony).
A Blu-Ray Disc stores digitally encoded data in the form of PITS.
Pits are spiral groves that runs from the center of the disc to its edge.
The pit size of a BD is 0.15 microns (more than twice as small as the pits on
The Data transfer rate of a BD is 36 Mbps.
A Blu-Ray disc will only work on a blue-violet laser and not on a red laser.
A BD enables us to …
Record HDTV without any quality loss.
Instantly skip to any spot on disc.
Record any program while watching other on the disc.
Edit programs recorded on the disc.
Access the web to download subtitles and other extra
Various hard coating technologies make Blu -Ray discs more
durable and family-friendly.
Hard coating technology provides resistance to:
BD’s are much more Stronger than today’s polycarbonate based
CD’s, DVD’s and HD DVD’s.
Better for random access of data.
Faster data seek.
Blue-Violet Laser v/s Red Laser
Audio and Picture Quality
Blu-ray discs are better armed than current DVD’s.
They come equipped with a secure encryption system which
consists of a unique ID that prevents video piracy and