BLU-RAY DISC PRESENTED BY DINESH.N 1NH02EC014
BLU-RAY DISCPRESENTED BY
DINESH.N1NH02EC014
IntroductionThe Demand for Data Storage
It is estimated that 250 megabytes of information is produced every year for each man, woman, and child (1 to 2 exabytes in total.)
Printed documents make up only .003% of this total.
History
Today’s Storage Technologies
Magnetic storage Optical storage Magneto-optical (MO) Solid state storage
Magneto-Optical Storage
Combines magnetic disk technologies with laser technology.
Can be read and written to over one million times.
Portable. Capacity is 2GB or more per disk. Faster than floppies and CDs, but slower
than hard drives.
CD-ROM
Works by reading bumps and low spots, or pits and lands on a disc with a laser.
Discs contain three layers: plastic, aluminum, and acrylic.
Aluminum layer reflects laser light, a detector can determine the difference between a pit and land.
CD-RWDisc Layers
Dual-Layer
Has two layers of data One layer is semi-transparent Laser can focus through it
Read the second layer Both layers are read from the same side Advantages:
– Hold twice as much as a single-layer disc– Long movies use higher data rates for better quality
DVD
Digital Versatile Disc / Digital Video Disc Red laser Backward-compatible with CD-ROMs Formats
– DVD-ROM– DVD-R/RW– DVD+R/RW– DVD-RAM
DVD-ROM
Works same as CD-ROM, but bumps are smaller and packed closer together.
Contains less error correction information (better error correction algorithm than CDs.)
Supports double layer storage, effectively doubling the storage area.
Drive does not spin at a constant speed which allows a constant data rate stream.
Blu-ray Disc (BD)
Developed by Blu-ray Disc Association (BDA) Recording, rewriting and playback of HD Blue-violet laser BD formats planned
– BD-ROM– BD-R– BD-RW
On a 25GB disc– 2 hours high-definition television (HDTV)– 13 hours standard-definition television (SDTV)– Take about 1 hour and 33 minutes
Blu-ray Disc
CD capable of storing 27GB. Uses blue laser as opposed to current red
laser. Blue laser can focus on smaller area,
allowing more information to be stored in a given area.
Blu-Ray Disc
Phase Change Recording
Type of recording technology Enables the disks to be written, erased, and rewritten Developed in late 1960s by Stanford Ovshinsky Involves a high intensity laser beam heating a
recording layer Alternate between an amorphous (formless) and a
crystalline state
Phase Change Recording
Alloy recording layer is a mix of silver, indium, antimony and tellurium
After heating to one particular temperature, the alloy will become crystalline
To erase or write over recorded data, the higher temperature laser is used, which results in the amorphous form
Used for both CD-RW, DVD-RW, DVD+RW and DVD-RAM
Blu ray vs DVD Capacity
DVD Vs Blu-Ray Construction
Benefit of using a blue-violet laser (405nm) Higher storage capacity
– Shorter wavelength than a red laser (650nm)– Focus the laser spot with greater precision– Data can be packed more tightly and stored in less space
Faster data transfer rate Support more formats of video compression
Blu-ray vs. HD DVD vs. DVD
Parameters BD HD-DVD DVD
Storage capacity 25GB/50GB 15GB/30GB 4.7GB/9.4GB
Laser Blue-violet laser Red laser
Laser wavelength 405nm 405nm 650nm
Numerical Aperture (NA) 0.85 0.60 0.60
Protection layer 0.1mm 0.6mm 0.6mm
Data transfer rate 36Mbps 36Mbps 11.08Mbps
Video compression MPEG-2MPEG-4 AVC
VC-1
MPEG-2MPEG-4 AVC
VC-1
MPEG-2
BD Disc and Recorder
Sony BDZ-S77 $2,150 $26 per disc Available in Japan only
– HDTV is not well established
Wait until 2006-2007
HD-DVD
High-definition or High Density DVD Also known as Advanced Optical Disc (AOD) Proposed by NEC/Toshiba Use the original DVD physical format Depend on new video encoding technology Use blue or violet lasers to read smaller pits Backward-compatible with DVD
Summary
Demand continues to grow. Cost per megabyte is decreasing. DVDs replacing older technologies. Convenience, cost, acceptance, and capacity
will drive new products. Several new technologies on the horizon,
providing reduced sizes with increased capacities and data transfer rates.
Conclusion
Reference
Websites– http://www.blu-ray.com/– http://www.dvddemystified.com/– http://www.howstuffworks.com