Blu-ray Disc Player

• Blu-ray disc players are simply devices that allow you to watch high-definition Blu-ray discs. These players need to be connected to a high-definition television to take advantage of the HD picture. The players can also be connected to a standard definition television, but the image will not look any better than a standard DVD image. Blu-ray technology was one of two HD video formats developed around the same time, but HD-DVD, the other format, fell out of favor and is no longer in production.
  
  

DVD Technology

• Digital disc technology works by creating microscopic bumps and holes on the surface of a DVD. These bumps and holes are arranged in lines that circle the disc. As the disc spins, a laser reads the lines and converts the bumps and holes into usable data. Once the laser is created, the color of the light, the numerical aperture of the lens and the thickness of the transparent cover on the disc, all combine to focus the laser on a specific point. The smaller that point, the more data the disc can store.
  
  

How Blu-ray is Better

• Blu-ray technology is superior to DVD technology in almost every way. The blue laser of Blu-ray has a smaller wavelength than a DVD laser, 405 nm versus 650 nm. The Blu-ray lens has a larger numerical aperature than a DVD lens and a much smaller cover layer. All this combines to make the Blu-ray laser focus on a spot that is 0.32 micrometers thick, compared to a DVD's 0.74 micrometers. Blu-ray technology also uses the H.264 compression format, allowing more video to be stored in less space. A single layer Blu-ray disc can hold up to 25 GB of information, compared to just a few GB on a standard DVD. Additional advances in adding multiple recording layers have allowed Blu-ray discs to hold up to 500 GB of information on a single disc.
  
  

Types of Blu-ray Players

• When Blu-ray players first came on the market, they were priced at close to $1,000. Over time that price has dropped significantly, down to just a few hundred dollars for high-quality players, and around a hundred dollars for some low-end models, as of 2011. Blu-ray players are also being bundled with other entertainment equipment, like Sony's Playstation 3 or Google TV. All Blu-ray players are able to display a picture with a 1080p resolution, but the television that the player is connected to will determine the actual resolution of the picture.