Blu-ray, also known as Blu-ray Disc (BD) is an optical disc storage medium developed by Blu-ray Disc Association. Blu-ray format was primarily developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data.
Blu-ray disc has the same physical dimensions as standard DVDs and CDs. The name Blu-ray derives from the blue-violet laser used to read and write data. Blu-ray is a combination of “Blue” (blue-violet laser) and “Ray” (optical ray). Letter “e” was intentionally left out so the term could be registered as a trademark.
The correct full name is Blu-ray Disc, not Blu-ray Disk (incorrect spelling).
Blu-ray Storage Capacity
- Single-layer disc can hold 25GB
- Dual-layer disc can hold 50GB
Blu-ray can fit over 9 hours of high-definition (HD) video and about 23 hours of standard-definition (SD) video on a 50GB disc.
Blu-ray Vs DVD
| Blu-ray | DVD | |
| Storage capacity | 25GB (single-layer)
50GB (dual-layer) |
4.7GB (single-layer)
8.5GB (dual-layer) |
| Laser wavelength | 405nm (blue laser) | 650nm (red laser) |
Video codecs supported by Blu-ray
- MPEG-2 – MPEG-2 is the codec used on regular DVDs, which allows backwards compatibility.
- MPEG-4 AVC – MPEG-4 AVC was developed by MPEG and VCEG , part of the MPEG-4 standard also known as H.264 (High Profile and Main Profile).
- SMPTE VC-1 – standard based on Microsoft’s Windows Media Video (WMV) technology.
Audio codecs supported by Blu-ray
- Linear PCM (LPCM) – (mandatory)
- Dolby Digital (DD) – (mandatory)
- Dolby Digital Plus (DD+)
- Dolby TrueHD
- DTS Digital Surround – (mandatory)
- DTS-HD High Resolution Audio
- DTS-HD Master Audio