Blu-ray is a much advanced optical disc technology when compared to a DVD or a CD. When the DVD came in, it was known for its fine and high definition video quality. But in the current scene, Blu-ray disc (BD) has swiftly taken over the DVD tradition with its remarkable features and altogether giving a superb visual experience.

Though the physical dimensions of both Blu-ray and DVD are identical, the major difference between them is their storage capacity. While a DVD can hold 4.7 GB on a single layer and 8.5 on a double layer; a Blu-ray disc (BD) can hold a capacity of 25 GB on a single layer and almost 50 GB on a double layer disc. This means a radical increase in the storage capacity up to five times in a Blu-ray disc. Technically, as the name suggests the Blu-ray disc depends on the blue - violet laser with a wavelength of 405 nm where as the DVD sticks to red laser with a wavelength of 650 nm. The shorter wavelength in Blu-ray allows to compresses the data into a very little space on the disc and also emphasizes on a better quality of being reproducible in amount and in performance.

About the experience, Blu-ray discs grant a supreme video resolution with a pixel array up to a maximum of 1920x1080 where as that of a DVD is just about 720x576. Therefore, the difference in the high definition display resolution between a Blu-ray disc (BD) and a DVD is quite obvious from the pixel range of both the formats. Moreover, the video bit rate is as fast as 40 Mbps in a Blu-ray disc while it is around 9.8 Mbps in a DVD. Even the data transfer rate in a Blu-ray disc is between 36 Mbps for simple files and 54 Mbps for an audio or a video file.

The video format in Blu-ray disc is compatible with MPEG-4 AVC and SMPTC VC-1 in addition to the compatibility with MPEG-2 generally allied with DVDs. In the case of audio, Blu-ray disc supports all formats of Linear PCM, Dolby Digital, Dolby Digital plus, Dolby True HD, DTS Digital Surround, DTS-HD unlike DVDs which support only Linear PCM, Dolby Digital and DTS Digital Surround. However, the compatibility depends on the players and recorders used. Reverse compatibility is also possible and is primarily dependent on the players and the content.

Blu-ray discs (BD) is available in formats of read-only (BD-ROM), recordable (BD-R) and rewritable (BD-RW) like any other DVD or a CD. The Blu-ray read-only format could be used for the circulation of high definition (HD) movies, games and other premium software. The other two formats recordable and rewritable could be used for recording high definition (HD) videos and storing data. These Blu-ray discs come with a hard coating.

Evidently, there is a massive difference between a Blu-ray disc (BD) and a DVD. The Blu-ray is a far sophisticated format of the optical disc with a lot of increased disc space. And now, the whole world including the leading electronic companies, motion picture studios, music and video recording media, gaming concerns etc are shifting to the Blu-ray technology for its unparalleled quality of high definition (HD) video and audio as well.