Blu-ray vs DVD: What difference?

Although Blu-ray discs look exactly the same as DVDs in size and shape, there are many differences between the media, including storage capacity, laser technology, disc construction, image resolution and player compatibility.

- “What does a Blu-ray disc look like?”

- would be “looks just like a DVD.”

So we have to dig a bit deeper to see the difference.

Storage Capacity & Image Resolution

DVD -- Optical disc

Storage capacity: 4.7GB (single layer), 8.5GB (dual layer)
Resolution: 720*480 (480i)

Blu-ray -- High-density optical disc

Storage capacity: 25GB (single layer), 50GB (dual layer)
Resolution: 1920*1080 (1080p)

Laser Technology

DVD -- DVD players use a red laser at 650nm wave length to read DVD discs.

As the disc spins the laser reads the information encoded on the media and produces an image and sound on your television.

Blu-ray -- Blu-ray players use a blue laser to read the stored information.

Blue laser wavelengths are shorter than the red at 405nm and are about two and a half times smaller in diameter than red lasers. This allows for closer and more precise reading of information stored on the disc.

Disc Construction

DVD- Since DVDs are read with a red laser the grooves on its underside need to be wide enough to accommodate the larger wavelength. Because the grooves are so far apart only 4.7 GB of information can be stored on each layer of the disc. DVDs also include a protective layer designed to resist scratching.

Blu-ray- The grooves on a Blu-ray disc are much thinner and closer together because the blue laser used to read the disc has a shorter wave length and is two and a half times thinner than the red laser. This allows the Blu-ray disc to squeeze almost five times as many grooves on to a disc exactly the same size as a DVD. Blu-ray also includes a protective layer to prevent scratches. This protective layer is physically thinner than the one on a DVD, but it has a hard coating that makes it more scratch resistant.

Player Compatibility

DVD Players- Blu-ray discs cannot and will not play in a standard DVD player, because the red laser used in DVD players is too large to read the tiny grooves in a Blu-ray disc.

Blu-ray Players- All Blu-ray players currently on the market (including the Playstation 3) are backwards compatible and will still play standard DVDs. However, the DVD image displayed, while still decent, will not be high definition quality like a Blu-ray disc.

>>Read more: Differences of a DVD player and a Blu-ray player

Other considerations

If you have altready purchased lots of Blu-rays and DVDs, should you rush out and buy a least Blu-ray player?

Yes, but only if you have an HDTV. Non-HD (or SDTV) televisions only display up to 480 lines of resolution, so connecting a Blu-ray player to an SDTV is a waste of resolution, at the meantime, you will not get the full expriences when watching a DVD on HDTV.

Let me put it this way: Consider your television. Now, imagine a picture on it that is “DVD quality.” From the top to the bottom of the screen, there will be 720 “lines” making up the picture. Not bad.

Now imagine the same image in “Blu-ray quality.” From top to bottom, in the same exact space, there will be 1080 lines making up the same image. Which one do you think shows more detail and looks sharper? In this case, more is better.

Avoid purchasing a New Blu-ray Player, and inserting Blu-ray / DVD into Blu-ray / DVD player per time, you are suggested to rip the Blu-ray / DVD into digital format for playing on any your devices anytime and anywhere.

You May Be Interested in This Item

Brorsoft Video Converter Ultimate / Brorsoft iMedia Converter for Mac

Price: $69.95 $49.95

> All-in-one Video Converter, DVD Ripper, Blu-ray Ripper, DVD/Blu-ray Copy software and Video Editor.