The main differentiating factor between DVD players and Blu-ray players is the laser technology used to play back and record data. Traditional DVD players utilize a red laser while Blu-ray players read from and write to the disc using a blue laser. Blu-ray players are reverse compatible with DVDs but a DVD player cannot be used to play Blu-ray discs.
The 405 nm wavelength of the blue laser technology dwarfs the 650 nm wavelength of the red laser; enabling Blu-ray players to focus more closely compared to DVD players. A single layer Blu-ray disc stores up to 27 GB of data while a double layered disc can hold 50 GB of data. This equates to about four hours of HDTV. Standard DVDs have a minimum storage capacity of 4.7 gigabytes.
The larger storage capacity of Blu-ray discs enables them to store more audio and video data. This coupled with an advanced laser technology has made Blu-ray the industry standard for optical data storage and high definition content. While the image of standard definition DVD is made up of 576 horizontal lines, Blu-ray almost doubles it with 1,080 horizontal lines. Due to their superior features, the prices of Blu-ray players are typically higher compared to that of DVD players.