Blu-ray or Blu-ray Disc is considered to be the new generation optical disc which has been developed jointly by BDA (Blu-ray Disc Association). Blu-ray Disc association is run by leaders of consumer electronics, personal computer manufacturers like Apple, Dell, Hitachi, HP, LG, etc. Blu-ray format has been developed for recording, rewriting and for playbacks of High Definition video (HD). It can also store large amount of data. The amount of space available in Blu-ray Disc is much greater than traditional DVD’s. These discs can store upto 25GB of data in a single layered disc and 50 GB of data on dual –layered disc. These qualities and capacities of Blu-ray disc will offer consumers a complete HD experience.
The optical discs such as DVD, DVD±R, DVD±RW, DVD-RAM takes use of red laser to read and write data. Whereas, Blu-ray uses blue-violet laser to read and write data, therefore, it is known as Blu-ray disc. Advantage of blue-violet laser is that it uses a shorter wavelength of 405 nm as compared to red laser of 650 nm which helps to focus the laser spot with greater precision. This results to pack the data more tightly and is stored in less space which results to fit more data in the disc. The size of the blu-ray disc is similar to the size of CD/DVD and can store data ranging from 25GB – 50GB. Recently, Pioneer has developed a Blu-ray disc which is able to store data upto 500GB on a single disc by increasing the layer size to 20.
Video and Audio Codecs:
Blu-ray supports the following video codecs.
- MPEG-2 which has been enhanced for HD experience which is also used for playback of DVDs and HDTV recording.
- MPEG-4 AVC is also the part of MPEG-4 standard which is also known as High profile and Main profile H.264
- SMPTE VC-1 – It is one of the standards which is based on Windows Media Video (WMV) technology.
Audio Codecs supported by Blu-ray:
- LPCM or Linear PCM – It is mandatory upto 8 channels of uncompressed audio.
- Dolby Digital (DD) – It is a kind of format used for DVDs where 5.1 channel surround sound is must.
- Dolby Digital Plus (DD+) – It is an optional extension of Dolby Digital where 7.1 channel surround sound is provided.
- Dolby True HD – It supports lossless encoding upto 8 channels of audio and is also optional.
Few more optional audio codecs are – DTS Digital Surround, DTS – HD High Resolution Audio, DTS – HD Master Audio.
Does Blu-ray Discs requires a Cartridge?
In recent times the development of low cost hard coating technologies has pushed the era of cartridge to older times. Hard-coating of these type of discs have been provided, which makes discs resistant to scratches and fingerprints which is not found on DVDs. This disc looks similar to any DVD or CD. Also, a new error correction system is provided with the Blu–ray Discs which makes it more robust and more efficient then what is used for DVDs.
Difference between DVD and Blu-ray:
|Storage Capacity||4.7GB – 8.5GB||25GB – 50GB|
|Laser Wavelength||650 nm||50 GB|
|Data transfer rate||11.08Mbps||36.0Mbps|
|Video/Audio Tranfer rate||10.08Mbps||54.0Mbps|
|Video resolution||720X480/720X576||1920X1080 (1080p)|
|Video bit rate||9.8Mbps||40.0Mbps|
Currently 200 leading consumer electronics uses Blu-ray disc in terms of electronics, personal computers, recording media, in video games and by music companies. This format is also supported by different Hollywood studios and many smaller studios. Many studios are planning to release their videos in these disc formats as it has many robust features as compared to DVDs and can store a large volume of data.