D2 (video format)
Encyclopedia
D-2 is a professional digital recording
videocassette format created by Ampex
and other manufacturers through a standards group of the Society of Motion Picture and Television Engineers
(SMPTE) and introduced at the 1988 NAB (National Association of Broadcasters) (NAB) convention as a lower-cost alternative to the D-1 format. Like D-1, D-2 video is uncompressed; however, it saves bandwidth and other costs by sampling a fully encoded NTSC
or PAL
composite video
signal, and storing it directly to magnetic tape
, rather than sampling analog
component video
. This is known as digital composite.
Ampex conceived of D-2 as a more practical solution for TV broadcasters since it could be inserted into existing broadcast airchain
s, television studio
and post-production
linear editing facilities without extensive redesign or modifications. This was because, among other things, in addition to its lower purchase and operating costs this digital composite video tape transport accepted standard analog video
inputs and outputs.
Four audio channels are available for editing as well as an analog cue channel. D-2 was the first digital recording video tape format to offer Sel-Sync
"read before write" (an Ampex term) also known as "preread" on Sony
tape recorders. Read before write allowed simultaneous playback and recording on the same VCR. For example a title could be super imposed over existing video already on the same video tape by playing the tape through a video switcher, adding the title, and recording the new composite image back onto the same location of the tape. This eliminated the need for an additional recorder and saved considerable time in linear editing. If the digital inputs and outputs are used with a digital composite switcher multigenerational performance is excellent. Hundreds of layers of video are possible without image quality loss using the digital inputs and outputs. If one were to edit using D2 VTRs with analog I/O then there is image loss due to repeated analog to digital conversions and the normal image defects contained in a studio's analog infrastructure. The first PreRead edit facility was Video-It, Inc in Culver City, California. Steven Fuiten was the first PreRead Editor to composite video using a full D2 digital system.
Ampex D-2 tape transports are extremely fast. A high speed search at 60 times playback speed with a recognizable color picture allowed three hours of videotape to be searched through in approximately three minutes.
D-2 used 19 mm (¾ inch) metal particle tape loaded into three different sized videocassettes. PCM-encoded audio and timecode are also recorded on the tape. Although the D-2 videocassette appear similar in appearance to the D1 (Sony)
format, they are not interchangeable.
D-2 had a relatively brief heyday. As of 2003, only a handful of broadcasters use the D-2 format, and even then only to access materials recorded when the format was more popular.
During its early stages, finished episodes of South Park
were hastily recorded to D-2 to be sent to Comedy Central
for airing in just a few days' time.
Panasonic
's competing composite digital format is known as D-3
.
Digital recording
In digital recording, digital audio and digital video is directly recorded to a storage device as a stream of discrete numbers, representing the changes in air pressure for audio and chroma and luminance values for video through time, thus making an abstract template for the original sound or...
videocassette format created by Ampex
Ampex
Ampex is an American electronics company founded in 1944 by Alexander M. Poniatoff. The name AMPEX is an acronym, created by its founder, which stands for Alexander M. Poniatoff Excellence...
and other manufacturers through a standards group of the Society of Motion Picture and Television Engineers
Society of Motion Picture and Television Engineers
The Society of Motion Picture and Television Engineers The Society of Motion Picture and Television Engineers The Society of Motion Picture and Television Engineers (SMPTE , founded in 1916 as the Society of Motion Picture Engineers or SMPE, is an international professional association, based in...
(SMPTE) and introduced at the 1988 NAB (National Association of Broadcasters) (NAB) convention as a lower-cost alternative to the D-1 format. Like D-1, D-2 video is uncompressed; however, it saves bandwidth and other costs by sampling a fully encoded NTSC
NTSC
NTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...
or PAL
PAL
PAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...
composite video
Composite video
Composite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...
signal, and storing it directly to magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
, rather than sampling analog
Analog video
Analog video is a video signal transferred by an analog signal. An analog color video signal contains luminance, brightness and chrominance of an analog television image...
component video
Component video
Component video is a video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video information that is transmitted or stored as three separate signals...
. This is known as digital composite.
Ampex conceived of D-2 as a more practical solution for TV broadcasters since it could be inserted into existing broadcast airchain
Airchain
In broadcast engineering for radio or television, the airchain or transmission chain is the path or route an audio or video signal takes on its way through a radio station or television station.The airchain begins with cameras, microphones, CD players, turntables, telephone hybrids, video tape...
s, television studio
Television studio
A television studio is an installation in which a video productions take place, either for the recording of live television to video tape, or for the acquisition of raw footage for post-production. The design of a studio is similar to, and derived from, movie studios, with a few amendments for the...
and post-production
Post-production
Post-production is part of filmmaking and the video production process. It occurs in the making of motion pictures, television programs, radio programs, advertising, audio recordings, photography, and digital art...
linear editing facilities without extensive redesign or modifications. This was because, among other things, in addition to its lower purchase and operating costs this digital composite video tape transport accepted standard analog video
Analog video
Analog video is a video signal transferred by an analog signal. An analog color video signal contains luminance, brightness and chrominance of an analog television image...
inputs and outputs.
Four audio channels are available for editing as well as an analog cue channel. D-2 was the first digital recording video tape format to offer Sel-Sync
Sel-Sync
Sel-Sync or Selective Synchronous recording is the process of selectively using some record heads as play back heads so that new signals can be recorded on other tracks in perfect sync with the existing tracks...
"read before write" (an Ampex term) also known as "preread" on Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
tape recorders. Read before write allowed simultaneous playback and recording on the same VCR. For example a title could be super imposed over existing video already on the same video tape by playing the tape through a video switcher, adding the title, and recording the new composite image back onto the same location of the tape. This eliminated the need for an additional recorder and saved considerable time in linear editing. If the digital inputs and outputs are used with a digital composite switcher multigenerational performance is excellent. Hundreds of layers of video are possible without image quality loss using the digital inputs and outputs. If one were to edit using D2 VTRs with analog I/O then there is image loss due to repeated analog to digital conversions and the normal image defects contained in a studio's analog infrastructure. The first PreRead edit facility was Video-It, Inc in Culver City, California. Steven Fuiten was the first PreRead Editor to composite video using a full D2 digital system.
Ampex D-2 tape transports are extremely fast. A high speed search at 60 times playback speed with a recognizable color picture allowed three hours of videotape to be searched through in approximately three minutes.
D-2 used 19 mm (¾ inch) metal particle tape loaded into three different sized videocassettes. PCM-encoded audio and timecode are also recorded on the tape. Although the D-2 videocassette appear similar in appearance to the D1 (Sony)
D1 (Sony)
D-1 is an SMPTE digital recording video standard, introduced in 1986 through efforts by SMPTE engineering committees. It started as a Sony and Bosch - BTS product and was the first major professional digital video format.- Format :...
format, they are not interchangeable.
D-2 had a relatively brief heyday. As of 2003, only a handful of broadcasters use the D-2 format, and even then only to access materials recorded when the format was more popular.
During its early stages, finished episodes of South Park
South Park
South Park is an American animated television series created by Trey Parker and Matt Stone for the Comedy Central television network. Intended for mature audiences, the show has become famous for its crude language, surreal, satirical, and dark humor that lampoons a wide range of topics...
were hastily recorded to D-2 to be sent to Comedy Central
Comedy Central
Comedy Central is an American cable television and satellite television channel that carries comedy programming, both original and syndicated....
for airing in just a few days' time.
Panasonic
Panasonic
Panasonic is an international brand name for Japanese electric products manufacturer Panasonic Corporation, which was formerly known as Matsushita Electric Industrial Co., Ltd...
's competing composite digital format is known as D-3
D3 video
D-3 is an uncompressed composite digital video videocassette format invented at NHK, and introduced commercially by Panasonic in 1991 to compete with Ampex's D-2. It uses half-inch metal particle tape at 83.88 mm/s . Like D-2, the video signal is sampled at four times the color subcarrier...
.
Models
- Sony
- DVR-10
- DVR-18
- DVR-20
- DVR-28
- DVC 80 Library Management System - LMS
- DVC 1000s Library Management System - LMS
-
-
- DCR-10 (sold by BTS)
- DCR-18 (sold by BTS)
- DCR-20 (sold by BTS)
- DCR-28 (sold by BTS)
-
- Ampex
- VPR-200
- VRP-250
- VPR-300
- Hitachi