D-2 (video)
Magnetic Tape | |
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
History
Ampex created the first D-2 video machine, the ACR-225 commercial spot player
Features
Like D-1, D-2 uses 19 mm (¾ inch) tape loaded into three different sized
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.
Acceptance
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]
Format Description
- 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
- 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
- ^ a b "Ampex History". Ampex. Archived from the original on 14 September 2013. Retrieved 14 September 2013.
- ^ ISBN 0-240-51287-1.
- ISBN 0-240-51302-9.
- ISBN 9781136024184.[page needed]
- ^ ISBN 9781136024184– via Google Books.
- ^ "Ampex history: 1988". Ampex. Archived from the original on 3 September 2013. Retrieved 18 September 2013.
- ^ "The Making of South Park". South Park Scriptorium. Retrieved 15 September 2013.
- ^ "MST3k 404 - Teenagers From Outer Space". Retrieved 3 January 2024.
- ^ (multiple authors). "Videotape Formats". LionLamb. Retrieved 19 September 2013.
External links
- allmobilevideo.com: D2 Specs
- Google Books: The History of Television, 1942 to 2000 By Albert Abramson
- Google Books: The Art of Digital Video, by John Watkinson
- lionlamb.us: Ampex Digital VTR Catalog
- lionlamb.us: Ampex ACR-225
- tech-notes.tv: Ampex history
- ampex.com: Ampex history
- D-1, D-2 & D-3: histories of digital video tape