The name “Blu-ray” is made up of the words “blue” (blue) and “Ray” together (Beam). Thus, the blue-violet laser beam is meant that reads the information from the disc. The missing “e” in “Blu-ray” is not a mistake: It falls under the table, so that the name “Blu-ray” can be registered as trademarks. This is not possible with everyday terms such as “blue”.
Operation of Blu-ray discs
Unlike the namesake of the Blu-ray, rays CD and DVD laser reddish. In principle, the Blu-ray Disc (BD), however, works as a CD and DVD: The disc has a data layer on the lined up the data as a string of pearls spirally from inside to outside. The laser beam scans the data track. Tiny pits in the track, the so-called pits, change the reflection of the laser light. Thus, the laser between “0” and can be “1” are different – this is the basic principle of the digital data storage. The differences to CD and DVD are in the structure of the disc. Since it can make fine focus the blue laser, the data on Blu-ray are packed together more closely. To fit on a Blu-ray disc well five times more data than a DVD of the same size.
What can the Blu-ray Disc better than the DVD?
The Blu-ray Disc saves movies in better picture and sound quality and with more extras. The reason: the higher storage capacity. A Blu-ray with a data layer capacity of 25 gigabytes (GB). A BD with two data layers even store up to 50 GB. Since 2010, Blu-ray discs with up to four layers and a capacity of 100 GB on the market are available. The increased capacity makes it possible to store several hours of film with high-resolution images.
HD Resolution: HD stands for “high definition”, ie “high resolution”. The movie images on Blu-ray have 1920×1080 pixels. These are well five times more pixels than a movie on DVD or on TV (720×576 pixels). Therefore, the images of the Blu-ray disc to show much more detail than DVD movies, such as highlights, sharper edges and finer backgrounds.
Better Sound Quality: How to DVDs is also stored on most Blu-ray disc, the sound in a home theater sound format. However, the discs also save lossless Kinoton: The formats Dolby TrueHD and DTS-HD Master Audio compress digital audio data without loss of sound. This enables better home cinema sound as a DVD or music CDs.
Menu display: The screen menu of a Blu-ray movie fades in on the current movie. In contrast, the playback stops at a DVD movie when the user invokes the menu.
CD, DVD and Blu-ray in technical comparison.
Double Video: Blu-ray player can display a second video in parallel with the film as a thumbnail image, such as a director’s commentary. The function is called “picture in picture” or “Bonus View”.
Internet: Blu-ray Discs can store links. The feature is called “BD Live” and offers extras such as latest movie trailers, online games or additional subtitles via the Internet. Blu-ray player with the “BD-Live” logo have a network output, so that they can be connected by cable to the DSL router.