What is Blu-ray?

Everything you need to know about Blu-ray

Official Blu-ray Disc Logo
Official Blu-ray Disc Logo. Blu-ray Disc Association

Blu-ray is one of the two major High Definition disc formats (the other being HD-DVD) that were introduced to consumers in 2006. The intention was to replace the current DVD standard in the U.S. and World market. However, in February 19, 2008 HD-DVD was discontinued and now Blu-ray is the only high definition disc-based format still in use, with DVD still also in use.

Blu-ray vs DVD

Blu-ray builds on the foundation established by DVD in the quest for a high quality TV viewing and listening experience.

Although DVD provides a very good viewing experience, it is not a high definition format. With the advent of both HDTV and the trend for larger TV screen sizes, as well as an increased use of video projectors, the limitations of DVD quality become more noticeable.

Blu-ray enables the consumer to see more depth, a wider range of color shades, and more detail in the image than from DVD, providing a true high definition TV viewing experience from pre-recorded material on a disc-based medium similar to that of a DVD.

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

The significance of blue laser technology is that a blue laser is narrower than a red laser, which means that it can be focused more precisely onto a disc surface. Taking advantage of this, engineers were able to make the "pits" on the disc where information is stored smaller and, thus, fit more "pits" onto a blu-ray disc than can be placed on DVD.

Increasing the number of pits creates more storage capacity on the disc, which is needed for the additional space required for recording high definition video.

In addition to increased capacity for video, Blu-ray also allows for more audio capacity than DVD. Instead of just including Standard Dolby Digital and DTS audio that we are familiar with on DVD (which are referred to as "lossy" audio formats because they are more highly compressed in order to fit onto a DVD disc), Blu-ray has the capacity to hold of up 8 channels of uncompressed audio in addition to a movie.

Overview of Blu-ray Disc Format Specifications

  • Disc Storage Capacity for Pre-recorded (BD-ROM) Playback Material: Single-layer (25GB) - Dual-layer (50GB)
  • Disc Storage Capacity for Home Recording: Single-layer (25GB) - Dual-layer (50GB). There are two types of recordable Blu-ray Discs, BD-R (Blu-ray Disc Record Once), and BD-RE (Blu-ray Disc Re-writable).  
  • Data Transfer Rate: 36 to 48 Mbps (Megabits per Second) average - capable of up to 54 MPS - This exceeds the 19.3 Mbps transfer rate approved for HDTV broadcasting. This means that Blu-ray not only handles a lot more information than DVD, but can also handle more information than HDTV television broadcasts are capable of.
  • Video Specifications: Compatible with full MPEG2 Encoding, as well as MPEG4 AVC (also know as H.264), and VC1 (based on the Microsoft WMV (Windows Media Video) format. Resolutions from 480i to 1080p (in either 2D or 3D - 3D compatibility on some players was added in 2010) can be implemented at the content producer's discretion.
  • 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 made since 2008 incorporate Dolby TrueHD/DTS-HD Master Audio on-board decoding, undecoded bitstream output, or both. In addition, most Blu-ray Disc players are also compatible with Dolby Atmos and DTS:X immersive surround sound audio encoding.
  • Audio/Video Connectivity: The Blu-ray format supports audio output from players via analog, digital optical/coaxial and HDMI connectivity. When players were first introduced, video output was allowed via composite, S-video, component, and HDMI - but as of 2013 all video connection support via composite, S-video, and component video was eliminated. This means that for any Blu-ray Disc player made from 2013 on, your TV must have an HDMI input in order to view video content.
  • Internet/Network Connectivity: Although the Blu-ray format supports networking and internet capabilities (BD-Live), built-in networking and ethernet ports on individual Blu-ray Disc Players is only required on players made after November 2007. Most players also now have a built-in WiFi connection option. Also, although not required as a part of the Blu-ray specifications, most Blu-ray Disc players also provide internet streaming capabilities, such as access to Netflix, Vudu, HuluPlus, etc.
  • Manufacturing and Software Support: Blu-ray is supported by all major manufacturers and movie studios including: Oppo Digital, Denon, Funai, Hitachi, LG, Panasonic, Onkyo, Pioneer, Philips, Samsung, Sharp, Sony, Toshiba, HP, Dell, Apple, TDK, Thomson, and Yamaha. Blu-ray is also supported on the software side by Sony/Columbia, Twentieth Century Fox, Disney, MGM, Paramount, Dreamworks, Lionsgate, Warner, and Universal, and others.
  • Backwards Compatibility Support: Although the Blu-ray Disc format is not compatible with previous formats - in other words, you cannot play a Blu-ray Disc on a DVD or CD player, except for a limited number of players introduced before 2008, all Blu-ray Disc players can play DVDs and CDs, and some can play additional disc and USB-based media file formats.

Ultra HD Blu-ray

In late 2015, the Ultra HD Blu-ray disc format was introduced. This format uses the same size discs as the Blu-ray format, but they are constructed so that they can fit more information that supports native 4K Resolution playback (this is not the same as 4K upscaling provided on some standard Blu-ray Disc players), as well as other video enhancement capabilities, such as wide color gamut and HDR.

You cannot play an Ultra HD Blu-ray Disc on a standard Blu-ray Disc player, but Ultra HD Blu-ray Disc players can play standard Blu-ray, DVD, and CD discs, and most can stream content from the internet - all at the manufacturer's discretion.

More Info

Go beyond the specifications and check out what else you need to know, what to buy, and how to set-up a Blu-ray Disc Player.

Before You Buy A Blu-ray Disc Player

The Best Blu-ray and Ultra HD Blu-ray Disc Players

How To Get Your Blu-ray Disc Player Up And Running