D-3

D-3 is an uncompressed composite videocassette format developed by NHK and introduced commercially by Panasonic. It was made to replace the one-inch tape formats within NHK at the time. 
== History ==
The D-3 format was launched in 1991, and it was intended to compete with D-2, developed by Ampex, which was more expensive. The format was developed by Japanese broadcaster NHK to replace their one-inch tapes, such as Type C. 
It is likely that D-3 has mostly been unused since the early 2000s, and even the format is now considered obsolete.
== Technical details ==
=== Video ===
Similar to D-2, the composite video signal is sampled at four times the color subcarrier frequency, with eight bits per sample.
=== Audio ===
Four channels of 48 kHz/16-20 bit PCM audio and other ancillary data are inserted during the vertical blanking interval.
== Camcorders ==
Camcorders were available which used this format, and D-3 camcorders are currently the only digital tape camcorders to use a lossless encoding scheme. Given that its a half-inch format, it meant that it was more practical for use in camcorders, unlike D-1 and D-2, both being 3 quarter-inch tape formats.
== Appearance ==
The colors vary, but are usually between gray and black. It uses grayish text.
== Competition ==
When it was launched in 1991, it was intended to compete with the D-2 format, made by Ampex. However, it later lost out to Digital Betacam, partly due to the DigiBeta cassettes being more simple to maintain.
== Usage ==
=== Video production ===
Japanese broadcaster NHK made the D-3 format as a replacement for their one-inch tape formats. 
=== Archival use ===
In the 1990s, the BBC launched a project to copy older tapes onto D-3 for archival use. However, due to its status as being obsolete, it is being transferred to formats such as LTO. There is doubt over whether the surviving D-3 machines will last long enough to play the 340,000 tapes of which the BBC holds.
== External links ==
* Safeguarding the BBC's archive - BBC
* D-3 (video) - Wikipedia
* D3 - Museum of Obsolete Media
* Digitising The BBC Archive - YouTube