The Difference Between Blu-ray and DVD
With the popularity of Blu-ray, many people still can't tell Blu-ray from DVD.
If you do not know the difference between Blu-ray and DVD exactly, you can find your answer from the table below.
|
Parameters
|
Blu-ray
|
DVD
|
|
Storage capacity
|
25GB (single-layer)
|
4.7GB (single-layer)
|
|
|
50GB (dual-layer)
|
8.5GB (dual-layer)
|
|
Laser wavelength
|
405nm (blue laser)
|
650nm (red laser)
|
|
Numerical aperture (NA)
|
0.85
|
0.60
|
|
Disc diameter
|
120mm
|
120mm
|
|
Disc thickness
|
1.2mm
|
1.2mm
|
|
Protection layer
|
0.1mm
|
0.6mm
|
|
Hard coating
|
Yes
|
No
|
|
Track pitch
|
0.32μm
|
0.74μm
|
|
Data transfer rate (data)
|
36.0Mbps (1x)
|
11.08Mbps (1x)
|
|
Data transfer rate (video/audio)
|
54.0Mbps (1.5x)
|
10.08Mbps (<1x)
|
|
Video resolution (max)
|
1920×1080 (1080p)
|
720×480/720×576 (480i/576i)
|
|
Video bit rate (max)
|
40.0Mbps
|
9.8Mbps
|
|
Video codecs
|
MPEG-2
|
MPEG-2
|
|
|
MPEG-4 AVC
|
-
|
|
|
SMPTE VC-1
|
-
|
|
Audio codecs
|
Linear PCM
|
Linear PCM
|
|
|
Dolby Digital
|
Dolby Digital
|
|
|
Dolby Digital Plus
|
DTS Digital Surround
|
|
|
Dolby TrueHD
|
-
|
|
|
DTS Digital Surround
|
-
|
|
|
DTS-HD
|
-
|
|
Interactivity
|
BD-J
|
DVD-Video
|
Blu-Ray uses a blue-violet laser as opposed to the red laser used on DVDs. This allows Blu-Ray discs to hold a lot more information on them than DVDs.
This increase in the amount of information that can be stored on a disc allows you to put High-Definition movies on a disc and not run out of space, since the average HD movie will take up about 15-20 GB of space.
If you have not seen an HD movie yet I would suggest stopping by your local Best Buy or Circuit City and looking at a Blu-Ray display. The images are sharper, brighter, and more detailed than any DVD movie. What manufacturers are trying to do is make the movie look as close to what you see in a real theater as possible, except for its a tenth the size and in your home.
Blu-Rays cannot be played in a traditional DVD player, which means that you will eventually have to buy a blu-ray player. However, all blu-ray players can play DVDs, and they upscale the images to look better on an HD screen, up to 1080p.
So, while you will have to get a new Blu-Ray player to play HD movies, you can still see all of your current DVDs on the same player, and they'll be enhanced.
In essence, Blu-Ray will replace DVD just as DVD replaced VHS and the CD replaced the Casette Tape.


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