Media type | Magnetic Tape, ¾-inch |
---|---|
Encoding | digital composite video |
Read mechanism | Helical scan |
Write mechanism | Helical scan |
Standard | interlaced (NTSC, PAL) |
Developed by | Ampex/Sony |
Usage | Video production |
Released | 1988 |
D-2 is a professional digital videocassette format created by Ampex and introduced in 1988 [1] at the NAB Show as a composite video alternative to the component video D-1 format. It garnered Ampex a technical Emmy in 1989. [1] Like D-1, D-2 stores uncompressed digital video on a tape cassette; however, it stores a composite video signal, rather than component video as with D-1. While component video is superior for advanced editing, especially when chroma key effects are used, composite video was more compatible with most analog facilities existing at the time.
Ampex created the first D-2 video machine, the ACR-225 commercial spot player [2] working with Sony, who had done some early research into composite digital video, [3] as a cost-effective solution for TV broadcasters with large investments in composite analog infrastructure such as video routers and switchers, since it could be inserted into existing analog broadcast facilities without extensive redesign or modifications. This was because D-2 machines accepted standard analog video and audio inputs and outputs. D-2 machines are capable of interfacing through either serial digital video or analog video connections. Four PCM audio channels are available for editing (an improvement over the then-popular Type C analog machines with two audio channels) as well as an analog cue channel and timecode, also with digital or analog connections.
Like D-1, D-2 uses 19 mm (¾ inch) tape loaded into three different sized videocassettes to support commercial spot playback as well as long-form programming such as movies. Although D-2 videocassette housings are nearly identical to their D-1 counterparts, they are not interchangeable due to D-2's metal particle tape formula, needed for its higher recording density. [2]
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.
The format uses helical scan, with an M wrap pattern in which the tape is wrapped around the head drum around the left and right side. [4] This records diagonal tracks, called helical tracks, using heads mounted on the drum which rotates at high speed. Both audio and video are recorded on the helical tracks. [5]
The D-2 offered read before write or preread functionality, which allowed simultaneous playback and recording on the same transport. [6] For example, a title could be superimposed 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 video editing. Steven Fuiten was the first PreRead Editor to composite video using a full D2 digital system.[ citation needed ]
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. [7] D-2 replaced Type C videotape for the mastering of LaserDiscs in the late 1980s.[ citation needed ]
D-2 was also used to send at least some episodes of Mystery Science Theater 3000 to Comedy Central for playback. [8]
D-2 was in widespread use for some ten years, as the computer-based video server (with fewer moving parts and correspondingly greater reliability) became available not long after its release. By 2003, only a handful of broadcasters continued to use the D-2 format, and even then only to access materials recorded on the format.[ citation needed ]
Panasonic introduced D-3 in 1991; it is very similar to D-2 as it uses a smaller cassette case.
Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises a series of digital images displayed in rapid succession, usually at 24, 25, 30, or 60 frames per second. Digital video has many advantages such as easy copying, multicasting, sharing and storage.
Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic tape can with relative ease record and play back audio, visual, and binary computer data.
VHS is a standard for consumer-level analog video recording on tape cassettes, introduced in 1976 by the Victor Company of Japan (JVC). It was the dominant home video format throughout the tape media period in the late 1970s through the early 2000s.
Videotape is magnetic tape used for storing video and usually sound in addition. Information stored can be in the form of either an analog or digital signal. Videotape is used in both video tape recorders (VTRs) and, more commonly, videocassette recorders (VCRs) and camcorders. Videotapes have also been used for storing scientific or medical data, such as the data produced by an electrocardiogram.
Ampex Data Systems Corporation is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor. The name AMPEX is an acronym, created by its founder, which stands for Alexander M. Poniatoff Excellence. Ampex operates as Ampex Data Systems Corporation, a subsidiary of Delta Information Systems, and consists of two business units. The Silicon Valley unit, known internally as Ampex Data Systems (ADS), manufactures digital data storage systems capable of functioning in harsh environments. The Colorado Springs, Colorado, unit, referred to as Ampex Intelligent Systems (AIS), serves as a laboratory and hub for the company's line of industrial control systems, cyber security products and services and its artificial intelligence/machine learning technology.
Helical scan is a method of recording high-frequency signals on magnetic tape, used in open-reel video tape recorders, video cassette recorders, digital audio tape recorders, and some computer tape drives.
D-1 or 4:2:2 Component Digital 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. SMPTE standardized the format within ITU-R 601, also known as Rec. 601, which was derived from SMPTE 125M and EBU 3246-E standards.
Betacam is a family of half-inch professional videocassette products developed by Sony in 1982. In colloquial use, Betacam singly is often used to refer to a Betacam camcorder, a Betacam tape, a Betacam video recorder or the format itself.
A video tape recorder (VTR) is a tape recorder designed to record and playback video and audio material from magnetic tape. The early VTRs were open-reel devices that record on individual reels of 2-inch-wide (5.08 cm) tape. They were used in television studios, serving as a replacement for motion picture film stock and making recording for television applications cheaper and quicker. Beginning in 1963, videotape machines made instant replay during televised sporting events possible. Improved formats, in which the tape was contained inside a videocassette, were introduced around 1969; the machines which play them are called videocassette recorders.
1-inch Type C Helical Scan or SMPTE C is a professional reel-to-reel analog recording helical scan videotape format co-developed and introduced by Ampex and Sony in 1976. It became the replacement in the professional video and broadcast television industries for the then-incumbent 2-inch quadruplex videotape open-reel format. Additionally, it replaced the unsuccessful type A format, also developed by Ampex, and primarily in mainland Europe, it supplemented the type B format, developed by the Fernseh division of Bosch.
A PCM adaptor is a device that encodes digital audio as video for recording on a videocassette recorder. The adapter also has the ability to decode a video signal back to digital audio for playback. This digital audio system was used for mastering early compact discs.
MII is a professional analog recording videocassette format developed by Panasonic in 1986 in competition with Sony's Betacam SP format. It was technically similar to Betacam SP, using metal-formulated tape loaded in the cassette, and utilizing component video recording.
M is the name of a professional analog videocassette format created around 1982 by Matsushita and RCA. Developed as a competitor to Sony's Betacam format, M used the same videocassette as VHS, much the same way that Betacam was designed to take advantage of cheap and readily available Betamax videocassettes,
1-inch Type A Helical Scan or SMPTE A is a reel-to-reel helical scan analog recording videotape format developed by Ampex in 1965, that was one of the first standardized reel-to-reel magnetic tape formats in the 1–inch (25 mm) width; most others of that size at that time were proprietary. It was capable of 350 lines.
1-inch Type B Helical Scan or SMPTE B is a reel-to-reel analog recording video tape format developed by the Bosch Fernseh division of Bosch in Germany in 1976. The magnetic tape format became the broadcasting standard in continental Europe, but adoption was limited in the United States and United Kingdom, where the Type C videotape format met with greater success.
2-inch quadruplex videotape was the first practical and commercially successful analog recording video tape format. It was developed and released for the broadcast television industry in 1956 by Ampex, an American company based in Redwood City, California. The first videotape recorder using this format was built the same year. This format revolutionized broadcast television operations and television production, since the only recording medium available to the TV industry until then was motion picture film.
D6 HDTV VTR is SMPTE videocassette standard. A D6 VTR can record and playback HDTV video uncompressed. The only D6 VTR product is the Philips, now Thomson's Grass Valley's Media Recorder, model DCR 6024, also called the D6 Voodoo VTR. The VTR was a joint project between Philips Digital Video Systems of Germany and Toshiba in Japan. The tape deck module was designed and made by Philips in Weiterstadt, Germany, and the digital processor module designed and made by Toshiba. Since there is no data compression, after 20 tape copies of multi generations there is no noticeable loss of quality. As a very high-end, costly system about 70 were sold to high-end post houses from about 2000 to 2005. The VTR had a data record option. The data module could record and play back 2k DPX files at 6 frames per second over a HIPPI connection. The VTR came in a data only model, or with a switch module, so the record deck could be used for both video and data recording. The tape deck was also sold stand alone as a giga bit recorder to record and playback raw data. Toshiba made the video tape for the VTR. The high price of the video tape limited the use of the VTR.
IVC 2 inch Helical scan was a high-end broadcast quality helical scan analog recording VTR format developed by International Video Corporation (IVC), and introduced in 1975. Previously, IVC had made a number of 1 inch Helical VTRs. IVC saw a chance to make a VTR that would have the quality of the then-standard 2 inch Quadruplex videotape format but with the advantages of helical scan. They then developed a VTR using this technology, the IVC Model 9000.
A videocassette recorder (VCR) or video recorder is an electromechanical device that records analog audio and analog video from broadcast television or other AV sources and can play back the recording after rewinding. The use of a VCR to record a television program to play back at a more convenient time is commonly referred to as time shifting. VCRs can also play back prerecorded tapes, which were widely available for purchase and rental starting in the 80s and 90s, most popularly in the VHS videocassette format. Blank tapes were sold to make recordings.