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{{Short description|Professional digital videocassette format}}
:''For other uses D2, see [[D2]] (disambiguation).''
{{Other uses|D2 (disambiguation){{!}}D2}}


{{Infobox media
'''D-2''' is a professional [[digital video]] [[Videotape#Going digital|tape 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) convention as a lower-cost alternative to the [[D1 SMPTE|D-1]] format. Like D-1, '''D-2''' video is [[Video compression|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 [[component video]]. This is known as [[digital composite]].
| name = D-2 (video)
| logo =
| image = Vsonyd2.jpg
| caption = Sony D-2 VCR
| type = [[Magnetic Tape]], ¾-inch
| encoding = [[digital video|digital]] [[composite video]]
| released=1988
| capacity =
| read = [[Helical scan]]
| write = [[Helical scan]]
| standard = [[Interlaced video|interlaced]] ([[NTSC]], [[PAL]])
| owner = [[Ampex]]/[[Sony]]
| use = [[Video production]]
| dimensions=
| extended from =
| extended to =
}}


'''D-2''' is a professional [[digital video|digital]] [[Videocassette#Cassette formats|videocassette]] format created by [[Ampex]] and introduced in 1988<ref name="history">{{cite web |url=http://www.ampex.com/l-history.html |title=Ampex History |website=Ampex |access-date=14 September 2013 |archive-url=https://web.archive.org/web/20130914035518/http://www.ampex.com/l-history.html |archive-date=14 September 2013 |url-status=dead }}</ref> at the [[NAB Show]] as a [[composite video]] alternative to the [[component video]] [[D1 SMPTE|D-1]] format. It garnered Ampex a [[Technology & Engineering Emmy Award|technical Emmy]] in 1989.<ref name="history" /> Like D-1, D-2 stores [[Video compression|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 [[Component video#Component versus composite|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 conceived of D-2 as a more practical solution for TV broadcasters since it could be inserted into existing broadcast chains and studio facilities without extensive redesign or modifications. This was because, among other things, in addition to its lower purchase and operating costs this D-2 composite digital tape transport accepted standard RS-170A analog inputs and outputs.


==History==
Four audio channels are available for editing as well as an analog cue channel. D-2 was the first digital tape format to offer "read before write" (an Ampex term) also known as "preread" on [[Sony]] recorders. Read before write allowed simultaneous playback and recording on the same VTR. For example a title could be super imposed over existing video already on the same video tape by playing the tape through a production 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. 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 around three minutes.
Ampex created the first D-2 video machine, the ACR-225 commercial spot player<ref name="Watkinson 1">{{cite book |last=Watkinson |first=John |title=The Art of Digital Video |year=1990 |publisher=Focal Press |isbn=0-240-51287-1}}</ref> working with Sony, who had done some early research into composite digital video,<ref name="Watkinson 2">{{cite book |last=Watkinson |first=John |title=The D-2 Digital Video Recorder |year=1990 |publisher=Focal Press |isbn=0-240-51302-9 |page=5}}</ref> as a cost-effective solution for TV broadcasters with large investments in [[composite video|composite]] analog infrastructure such as [[video router]]s and [[video switcher|switchers]], since it could be inserted into existing analog broadcast facilities without extensive redesign or modifications. This was because D-2 machines accepted standard [[Composite video|analog video]] and audio inputs and outputs. D-2 machines are capable of interfacing through either [[Serial digital interface#Standards|serial digital video]] or analog video connections. Four [[Pulse-code modulation|PCM]] audio channels are available for editing (an improvement over the then-popular [[Type C videotape|Type C]] analog machines with two audio channels) as well as an analog cue channel and [[timecode]], also with [[AES3|digital]] or [[XLR connector|analog]] connections.


==Features==
D-2 used 19 mm (¾ inch) metal particle tape loaded into three different sized [[Videocassette|cassette]]s. [[PCM]]-encoded audio and [[timecode]] are also recorded on the tape. Although the D-2 tapes are similar in appearance to the [[D-1]] format, they are not interchangeable.
Like D-1, D-2 uses 19&nbsp;mm (¾ inch) tape loaded into three different sized [[videocassette]]s to support [[Television advertisement|commercial spot]] playback as well as long-form programming such as movies. Although D-2 videocassette housings are {{abbr|nearly identical|(except for certain identifier notches)}} to their [[D-1 (Sony)|D-1]] counterparts, they are not interchangeable due to D-2's [[metal particle tape]] formula, needed for its higher recording density.<ref name="Watkinson 1" />


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 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.


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.<ref>{{cite book |url=https://books.google.com/books?id=8YDOAwAAQBAJ |title=Broadcast Engineer's Reference Book |date=12 November 2012 |isbn=9781136024184}}{{pn|date=June 2023}}</ref> 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.<ref name="auto">{{Cite book|url=https://books.google.com/books?id=8YDOAwAAQBAJ&dq=dv+9000+rpm&pg=PA473|title=Broadcast Engineer's Reference Book|first=E. P. J.|last=Tozer|date=November 12, 2012|publisher=CRC Press|isbn=9781136024184 |via=Google Books}}</ref>
[[Panasonic]]'s competing composite digital format is known as [[D3 video|D-3]].


The D-2 offered ''read before write'' or ''preread'' functionality, which allowed simultaneous playback and recording on the same transport.<ref>{{cite web |url=http://www.ampex.com/l-history/120-1988.html |title=Ampex history: 1988 |author=<!--Staff writer(s); no by-line.--> |website=Ampex |access-date=18 September 2013 |archive-url=https://web.archive.org/web/20130903012529/http://www.ampex.com/l-history/120-1988.html |archive-date=3 September 2013 |url-status=dead }}</ref> 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|date=November 2015}}
==Models==


==Acceptance==
*Sony
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.<ref>{{cite web |url=http://www.spscriptorium.com/SPinfo/MakingOfSouthPark.htm |title=The Making of South Park |author=<!--Staff writer(s); no by-line.--> |website=South Park Scriptorium |access-date=15 September 2013}}</ref> D-2 replaced [[Type C videotape]] for the mastering of [[LaserDisc]]s in the late 1980s.{{cn|date=February 2024}}
**DVR-10
**DVR-18
**DVR-20
**DVR-28
**DVC 80 Library Management System - LMS
**DVC 1000s Library Management System - LMS


D-2 was also used to send at least some episodes of [[Mystery Science Theater 3000]] to [[Comedy Central]] for playback.<ref>{{cite web |url=https://www.youtube.com/watch?v=vnOzPbjM4cQ |title=MST3k 404 - Teenagers From Outer Space |access-date=3 January 2024}}</ref>
***DCR-10 (sold by BTS)
***DCR-18 (sold by BTS)
***DCR-20 (sold by BTS)
***DCR-28 (sold by BTS)


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|date=September 2013}}
*Ampex
**VPR-200
**VRP-250
**VPR-300


[[Panasonic]] introduced [[D3 video|D-3]] in 1991; it is very similar to D-2 as it uses a smaller cassette case.
*Hitachi


==Format Description==
<gallery>
* General:
Image:D2-ampex.JPG|Ampex D2 VTR
** Format name: D2 digital
Image:Vsonyd2.jpg|Sony D2
** SMPTE type: D2
</gallery>
** Format type: digital composite
** Scanning system: multi head segmented helical
** Year introduced: 1988
** Developer: Ampex/Sony
* Physical Data:<ref>{{cite web |url=http://www.lionlamb.us/quad/format.html |title=Videotape Formats |author=(multiple authors) |website=LionLamb |access-date=19 September 2013}}</ref>
** Tape width: 19&nbsp;mm
** Tape speed(s): 5.19 ips
** Tape thickness: .55 mils
** Playing time(s): 32, 94, 208 minutes (Small, Medium, Large cassette sizes)
** Headwheel (head drum) diameter: 2.95" (96.4 mm)<ref name="auto"/>
** Helical track width: 35.2 microns<ref name="auto"/>
** Speed: 7200 rpm<ref name="auto"/>
** Head-to-tape writing speed: 1078 in/sec.
** Sampling rate: 4fsc (14.31818&nbsp;MHz for NTSC)
** No. of bits: 8
** Data rate: 60.1&nbsp;MB/sec (480.8&nbsp;Mbps)
* Audio:
** No. of digital channels: 4
** Sampling rate: 48&nbsp;kHz
** No. of bits: 20


==See also==
==Models==
[[File:Sony DVR-28 BKDV-201 of China TV 20150912.jpg|thumb|Sony DVR-28]]
*[[D5 HD|D-5 HD]]
*Ampex
**VPR-200, VPR-250, VPR-300
**ACR-225 Commercial Spot Player (robotic tape system)
*Sony
**DVR-10, DVR-18, DVR-20, DVR-28
**DCR-10, DCR-18, DCR-20, DCR-28 (sold by [[Broadcast Television Systems Inc.|BTS]])
**DVC 80, DVC 1000s LMS (Library Management System)


==References==
<references/>


==External links==
{{homevid}}
*[https://web.archive.org/web/20100129002316/http://www.allmobilevideo.com/rentals/R_decks_d2.htm allmobilevideo.com: ''D2 Specs'']
*[https://books.google.com/books?id=JMTnTBmt7F0C&dq=D-2+sony+vtr&pg=PA238 Google Books: ''The History of Television, 1942 to 2000'' By Albert Abramson]
* [https://books.google.com/books?id=dMjfQo98CLUC Google Books: ''The Art of Digital Video'', by John Watkinson]
*[http://www.lionlamb.us/quad/ampexdig.html lionlamb.us: ''Ampex Digital VTR Catalog'']
*[http://www.lionlamb.us/quad/acr225.html lionlamb.us: ''Ampex ACR-225'']
*[http://www.tech-notes.tv/History&Trivia/Television%20Recording/Ampex/ampex.htm tech-notes.tv: ''Ampex history'']
*[https://web.archive.org/web/20130914035518/http://www.ampex.com/l-history.html ampex.com: ''Ampex history'']
*[https://thegreatbear.net/video-tape/d1-d2-d3-histories-digital-video-tape/ D-1, D-2 & D-3: histories of digital video tape]
{{Video storage formats}}


[[Category:Video storage]]
[[Category:Video storage]]
[[Category:Composite video formats]]

[[Category:Videocassette formats]]
[[it:D2 (formato di videoregistrazione)]]
[[ja:D2-VTR]]

Latest revision as of 21:09, 25 June 2024

For other uses, see D2.
D-2 (video)
Sony D-2 VCR
Media typeMagnetic Tape, ¾-inch
Encodingdigital composite video
Read mechanismHelical scan
Write mechanismHelical scan
Standardinterlaced (NTSC, PAL)
Developed byAmpex/Sony
UsageVideo production
Released1988

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.

History[edit]

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.

Features[edit]

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]

Acceptance[edit]

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.

Format Description[edit]

  • General:
    • Format name: D2 digital
    • SMPTE type: D2
    • Format type: digital composite
    • Scanning system: multi head segmented helical
    • Year introduced: 1988
    • Developer: Ampex/Sony
  • Physical Data:[9]
    • Tape width: 19 mm
    • Tape speed(s): 5.19 ips
    • Tape thickness: .55 mils
    • Playing time(s): 32, 94, 208 minutes (Small, Medium, Large cassette sizes)
    • Headwheel (head drum) diameter: 2.95" (96.4 mm)[5]
    • Helical track width: 35.2 microns[5]
    • Speed: 7200 rpm[5]
    • Head-to-tape writing speed: 1078 in/sec.
    • Sampling rate: 4fsc (14.31818 MHz for NTSC)
    • No. of bits: 8
    • Data rate: 60.1 MB/sec (480.8 Mbps)
  • Audio:
    • No. of digital channels: 4
    • Sampling rate: 48 kHz
    • No. of bits: 20

Models[edit]

Sony DVR-28
  • Ampex
    • VPR-200, VPR-250, VPR-300
    • ACR-225 Commercial Spot Player (robotic tape system)
  • Sony
    • DVR-10, DVR-18, DVR-20, DVR-28
    • DCR-10, DCR-18, DCR-20, DCR-28 (sold by BTS)
    • DVC 80, DVC 1000s LMS (Library Management System)

References[edit]

  1. ^ a b "Ampex History". Ampex. Archived from the original on 14 September 2013. Retrieved 14 September 2013.
  2. ^ a b Watkinson, John (1990). The Art of Digital Video. Focal Press. ISBN 0-240-51287-1.
  3. ^ Watkinson, John (1990). The D-2 Digital Video Recorder. Focal Press. p. 5. ISBN 0-240-51302-9.
  4. ^ Broadcast Engineer's Reference Book. 12 November 2012. ISBN 9781136024184.[page needed]
  5. ^ a b c d Tozer, E. P. J. (November 12, 2012). Broadcast Engineer's Reference Book. CRC Press. ISBN 9781136024184 – via Google Books.
  6. ^ "Ampex history: 1988". Ampex. Archived from the original on 3 September 2013. Retrieved 18 September 2013.
  7. ^ "The Making of South Park". South Park Scriptorium. Retrieved 15 September 2013.
  8. ^ "MST3k 404 - Teenagers From Outer Space". Retrieved 3 January 2024.
  9. ^ (multiple authors). "Videotape Formats". LionLamb. Retrieved 19 September 2013.

External links[edit]

Retrieved from "https://en.wikipedia.org/w/index.php?title=D-2_(video)&oldid=1230993099"