What is Blu-ray? All you need to know about Blu-ray

Blu-ray is one of the two main formats of high-definition discs (the other is HD-DVD) which was presented to consumers in 2006 to expand the depth, color, and detail that viewers could see in the images. The intention was to replace the DVD standard in the US and global market. However, on February 19, 2008, the HD-DVD was locked, with Blu-ray leading HD playback, but the DVD is still in use.

Blu-ray vs DVD

Blu-ray is based on the foundations established by the DVD in the search for a superior TV viewing and listening experience. Although the DVD is much better than the previous formats, like VHS and Laserdisc, it is not a high definition format.

With the advent of HDTV, the tendency to larger TV screens and greater use of video projectors, the limits of DVD quality become more evident.

Blu-ray allows viewers to see more depth, a wider range of color shades and more detail in the image than the DVD.

Where the DVD uses Red Laser technology, the Blu-ray Disc format uses Blue Laser technology and sophisticated video compression to achieve high-definition video playback on the same disc as a standard DVD.

A beam of blue laser light is narrower than a red laser, which means it can focus more precisely on the surface of the disc. Taking advantage of this, the “pits” on the disk where the information is stored can be much smaller.

This means that you can place more “data” on a Blu-ray disc than on a DVD. Increasing the number of pits creates more disk storage capacity, necessary for the additional space required for high-definition video.

In addition to increasing video capacity, Blu-ray also offers greater audio capacity than DVD. Instead of including only standard Dolby Digital and DTS audio that is used on DVDs (which are referred to as “lossy” audio formats because they are more compressed to fit on a DVD disc), Blu-ray has the ability to hold those formats and more, with up to 8 uncompressed audio channels in addition to video content.

Blu-ray Disc format specifications

Storage capacity on disk for pre-recorded playback material (BD-ROM): single layer (25 GB) – double layer (50 GB)

Storage capacity on disk for recording: single layer (25 GB) – double layer (50 GB). There are two types of recordable Blu-ray discs, BD-R (Blu-ray Disc Record Once) and BD-RE (rewritable Blu-ray Disc).

Data transfer rate: from 36 to 48 Mbps (Megabits per second) on average – capable up to 54MPS. This exceeds the transfer rate of 19.3 Mbps approved for HDTV transmissions. This means that Blu-ray not only handles much more information than DVDs, but it can also handle more information than HDTV television broadcasts are capable of.

Video specifications: compatible with full MPEG2 encoding, as well as with MPEG4 AVC (also known as H.264) and VC1 (based on the Microsoft WMV format – Windows Media Video). Resolutions from 480i to 1080p (in 2D or 3D – 3D compatibility on some readers was added in 2010) can be implemented at the discretion of the content producer.

Audio specifications: only Dolby Digital, DTS and Uncompressed PCM are required on all players. The following audio formats are optional- Dolby Digital Plus, Dolby TrueHD, DTS- HD Master Audio. However, almost all Blu-ray Disc players produced since 2008 incorporate integrated Dolby TrueHD / DTS-HD Master Audio decoding, un-encoded bitstream output or both. Furthermore, most Blu-ray Disc players are also compatible with the immersive Dolby Atmos and DTS- X surround sound encoding.

Audio/video connectivity: Blu-ray supports the audio output of the players via analog, optical/coaxial digital and HDMI connectivity. When readers were introduced for the first time, video output was allowed via composite, S-video, component, and HDMI, but since 2013 all support for video connection via composite, S-video and component video has been eliminated. This means that for any Blu-ray Disc player made since 2013, the TV must have an HDMI input to view video content. Furthermore, there is a decreasing number of readers offering analog or digital optical audio outputs.

Internet/network connectivity: although the Blu-ray format supports network and Internet (BD-Live) features, the integrated network and Ethernet ports on individual Blu-ray Disc players are only required on readers built after November 2007. Most readers even now must have an integrated WiFi connection option. Furthermore, although not required as part of the Blu-ray specification, most Blu-ray Disc players also offer Internet streaming capabilities, such as access to Netflix, Vudu, Hulu, Amazon Video, etc.

Support for backward compatibility– although the Blu-ray Disc format is not compatible with the previous formats, in other words, it is not possible to play a Blu-ray Disc on a DVD or CD player, but all Blu-ray players ray discs can play DVDs and CDs, and some can play other disc-based media formats and USB.

Ultra HD Blu-ray

At the end of 2015, the Ultra HD Blu-ray Disc format was introduced. This format uses the same dimensions as Blu-ray discs, but they are constructed in such a way that they can contain more information that supports native playback with 4K resolution (not the same as 4K upscaling provided on some standard Blu-ray Disc players), like other video enhancement features, such as a wide range of colors and HDR .

You can’t play an Ultra HD Blu-ray disc on a standard Blu-ray Disc player, but Ultra HD Blu-ray Disc players can play Blu-ray discs, DVDs, and standard CDs, and most can play streaming content from the Internet – all at the discretion of the manufacturer.


Blu-ray is a disc-based video format that is suitable for viewing on HD TVs and can also be used with 4K Ultra HD TV, although the new Ultra HD Blu-ray format meets these needs even better.

For more details on Blu-ray, go over the specifications discussed above and find out what else you need to know, what to buy and how to set up a Blu-ray Disc player.

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About Author

Samuel Afolabi is a lazy tech-savvy that loves writing almost all tech-related kinds of stuff. He is the Editor-in-Chief of TechVaz. You can connect with him socially :)

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