In 2010, digital video discs (DVDs) and Blu-ray discs are the norms in home entertainment. Despite how they look, however, Blu-rays and DVDs are different kinds of technology, just as DVD meant a 5 to 10 times increase in storage capacity compared to CD, Blu-ray Disc will increase DVD capacity by 5 to 10 times. Several key differences have made the Blu-ray disc the official successor to the DVD.
Capacity
One of the biggest differences between DVDs and Blu-ray discs is storage capacity. A Blu-ray disc can hold about 25 GB of data. Dual layer Blu-ray discs can hold as much as 50 GB of data. The larger storage capacity of a Blu-ray disc is a clear advantage over standard DVDs, allowing higher quality of video and audio to be stored. A standard DVD can hold up to 4.7 gigabytes (GB) of data. Dual layer DVDs can hold about 8.5 - 8.7 GB of data, which is still much less than even the smallest Blu-ray discs.
Laser
A DVD is read using a red laser while a Blu-ray is read using a blue laser, hence the latter's name. The Blu-ray's laser wavelength is 405 nanometers (nm), and the DVD's is 650 nm, which enables the Blu-ray disc to provide sharper images.
Data Transfer
The data transfer rate for a video/audio DVD is 10.08 (megabits per second0 Mbps and for a video/audio Blu-ray disc is 54 Mbps.
Resolution
Because of the larger storage capacity of the Blu-ray disc, it can hold much more video and audio data, allowing for much higher quality of video and audio. Blu-ray discs support resolutions up to 1920x1080 and frame rates up to 29.97 at the highest resolution (frame rates up to 59.94 at lower resolutions). Blu-ray discs can playback in true HD format. Due to the much lower storage capacity of a standard DVD, it is not possible to have HD video quality on a DVD.
Availability
Blu-ray is a newer technology than DVD, which means not all of the older movies are available yet in Blu-ray format. DVD has been around since 1996 and has had years to develop its library. Almost every movie ever made is available in DVD format and when renting movies you'll have a much easier time finding the movie in DVD format than Blu-ray.
Thickness
A DVD and Blu-ray disc are identical in thickness (120mm), but each disc's protection coating is different. The DVD has a protection coating that is 0.6mm thick while the Blu-ray disc has one that is 0.1mm thick. In addition, the Blu-ray's coating is hard, while the DVDs is not.
Cost
The price of Blu-ray players is more affordable than ever. Blu-ray discs themselves, for movies and TV shows, cost a little more than standard DVDs, but the gain from Blu-ray far outweighs the moderately increased prices.
