Tagged: 120mm

The diameter of the Compact Disc, and hence the diameter of most optical disc formats since that time

Blu-ray Disc Recordable Erasable (BD-RE) (2006 – )

Blu-ray Disc Recordable Erasable (BD-RE) is a high-capacity optical disc that can be erased and re-recorded multiple times, and is a type of Blu-ray Disc that can be read in all Blu-ray Disc drives. The similar BD-R discs can only be written to once.

BD-RE drives can be found in computers and personal video recorders (PVRs).

Disc capacities are 25 GB for single-layer discs, 50 GB for double-layer discs, 100 GB for triple-layer, and 128 GB for quadruple-layer.

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High Definition Compatible Digital (HDCD) (1995 – )

High Definition Compatible Digital (usually known as HDCD) is a Compact Disc based music format that uses a proprietary encoding system to provide increased dynamic range over standard Compact Discs by encoding 20-bits worth of data in the 16-bit digital audio signal.

It was originally developed by Pacific Microsonics, and the first HDCD releases were in 1995. The technology was subsequently purchased by Microsoft in 2000, and although the official HDCD website was taken down in 2005, there continue to be small numbers of HDCD releases.

HDCD discs can be played in standard Compact Disc players (although there are some claims of distortion), but to take advantage of the claimed improvements in quality requires a HDCD-compatible player, or later versions of Windows Media Player on PCs.

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Blu-ray Disc Recordable (BD-R) (2006 – )

Blu-ray Disc Recordable (BD-R) is a write-once high-capacity optical disc, and a type of Blu-ray Disc that can be read in all Blu-ray Disc drives. The similar BD-RE is a rewritable version.

BD-R drives can be found in computers and personal video recorders (PVRs).

Disc capacities are 25 GB for single-layer discs, 50 GB for double-layer discs, 100 GB for triple-layer, and 128 GB for quadruple-layer.

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Phase-change Dual (PD) disk (1995 – 1998)


Introduced by Panasonic in 1995, the Phase-Change Dual (PD) disk is a rewritable optical disc similar to later technologies like CD-RW. They have a capacity of 650MB and could be rewritten 500,000 times.

Like DVD-RAM disks, they are enclosed in a protective cartridge.

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CD-BGM (1989 – late 2000s)

Audio CDi (front)CD-BGM (CD-BackGround Music) was an audio format for background music systems, introduced by Philips in collaboration with several companies in the background music business in 1989.

Philips used a compression algorithm that was being developed for CD-i, ADPCM (Adaptive Delta Pulse Code Modulation). Audio is mono, and is stored at Level A – C compression, allowing up to 4,8 or 16 hours of music.

Because of Philips’ work on the CD-i at the time, all CD-BGM discs are compatible with the CD-i system even though the CD-i system wasn’t introduced until 1991, and can be played in CD-i players. CD-BGM is often referred as audio-only CD-i, and meets the Green Book specifications for CD-i.

It was not the intention for CD-BGM discs to be played on domestic CD-i players, and dedicated players were offered by companies working in the background music industry. Usually, these used a caddy system similar to early CD-ROMs, but much more secure as the discs were often used in unfavourable environments such as restaurants and planes. The discs were usually part of a subscription, and were returned to the supplier to get new ones.

Super High Material CD (2007 – )

Super High Material (SHM) CD is a type of Compact Disc that uses an improved transparency polycarbinate resin as its transparent substrate, and this is claimed to provide a clearer medium for the reading of the data and so reduce read errors and improve the sound quality.

The polycarbinate resin was developed by JVC and Universal Music Japan during research into LCD manufacturing, and SHM-CDs began to be released in 2007.

SHM-CDs are fully compliant with the Red Book standards and play in any Compact Disc player.

Almost all of the releases have come from Japan, and have mostly been re-releases.

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CD Video (1987 – 1992)

CD Video (CDV) was a combined audio and video format introduced in 1987 that combined the technologies of Compact Disc and LaserDisc. The discs were the same size as a Compact Disc, and contained up to 20 minutes worth of audio information (around 4-5 tracks) that could be played on any audio Compact Disc player. They also contained up to 5 minutes of analogue video information, which could be played back on a newer LaserDisc player capable of playing CD Video discs.

CD Video discs have a distinctive gold colour, to differentiate them from regular silver-coloured Compact Discs.

Over 170 CD Video titles were released, but the format met with limited success as a LaserDisc player was required to play the video portion. CD Video disappeared from the the US and European markets in 1990, but continued to be popular in Japan until 1992.

A version of CD Video called Video Single Disc (VSD) was also released, but this only had a LaserDisc analogue video track (occupying the whole of the disc) and no audio Compact Disc audio tracks.

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Blu-ray Disc (2006 – )

Blu-ray Disc is an optical disk format for high-definition video. The standard was developed by the Blu-ray Disc Association (a consortium of companies, including Sony) and was released in 2006.

The discs themselves are the same size as DVD (120mm), but are capable of storing 25 GB per layer, with dual-layer discs being the industry standard for movies on Blu-ray Disc. Mini Blu-ray Discs (80mm) are also available, similar to MiniDVD.

Information is stored at a much higher density than DVD due to the use of blue lasers.

From its introduction until 2008, Blu-ray competed with HD-DVD, which was launched a few months prior to Blu-ray. By as early as January 2007, Blu-ray was outselling HD-DVD, helped by Sony including Blu-ray Disc support in the PlayStation 3.

As well as motion pictures, Blu-ray is used for distributing games for consoles such the Sony PlayStation 3 and 4, and the Xbox One, and recordable (BD-R) and rewritable versions (BD-RE) are also available for data or video storage. In 2013, High Fidelity Pure Audio was launched, using audio-only Blu-ray Discs.

Blu-ray Disc titles usually ship in packages similar to but slightly smaller than a standard DVD case, with the format prominently displayed across the top of the case. Some Blu-ray Discs come packaged with a DVD version of the film, as well as digital copies that can be played on computers.

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High Fidelity Pure Audio (2013 – )

High Fidelity Pure Audio is an audio format using Blu-ray optical discs, and launched by Universal Music Group in 2013.

The audio content is uncompressed, and where standard Compact Disc audio is sampled at 44.1 KHz at 16 bits, High Fidelity Pure Audio’s sampling rate is between 96 KHz and 192 KHz at 24 bits.

Previous attempts to offer hi-fi sound included Super Audio CD (SACD) and DVD-Audio, neither of which gained a significant market share.

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DVD-Video (1998 – )

DVD-Video is a digital optical disc storage format for video playback, developed by Philips, Sony, Toshiba and Panasonic. It was initially available in Japan in 1995, and reached Europe in 1998. The first movie to be released on the new DVD-Video format was Twister, which also happened to be the last film released on HD-DVD.

In 1993, two new optical disc video formats were being developed, Multimedia Compact Disc (MMCD), backed by Philips and Sony, and the Super Density (SD) disc, supported by a number of other manufacturers. Eventually, a joint standard was agreed.

Movie distributors adopted the DVD-Video format to replace the ubiquitous VHS as it produced superior picture and sound quality, could provide interactivity, and the storage capacity allowed for extras or bonus features such as audio commentaries, deleted scenes and trailers. Players were also cheaper to manufacture than complex video tape machines.

Each DVD-Video disc contains one or more region codes, denoting the area(s) of the world in which distribution and playback are intended. The commercial DVD player specification dictates that a player must only play discs that contain its region code but in practice, many DVD players allow playback of any disc, or can be modified to do so.

Currently, DVD-Video is the dominant form of home video distribution worldwide, although in Japan it was surpassed by Blu-ray Disc in 2006. It is now, however, facing competition from video on demand services.

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