1-inch Type B Helical Scan orSMPTE B is areel-to-reelanalog recordingvideo tape format developed by the BoschFernseh division ofBosch in Germany in 1976. The format uses 1-inch-wide (25 mm)magnetic tape and became the broadcasting standard in continental Europe, but adoption was limited in the United States and United Kingdom, where theType C videotape format met with greater success.[1][2][3][4]
The tape speed allowed 96 minutes on a large reel (later 120 minutes), and used 2 record/playback (R/P) heads on the drum rotating at 9,000 RPM with a 190-degree wrap around a very small head drum, recording 52 video lines per head segment. A single video frame or field was recorded across 6 tracks in the tape. The format only allowed for play, rewind and fast forward.[5] Video is recorded on an FM signal with a bandwidth of 5.5 MHz. Three longitudinal audio tracks are recorded on the tape as well: two audio and oneLinear timecode (LTC) track.[6][7][8] BCN 50 VTRs were used at the1980 Summer Olympics inMoscow.[9]
The format required an optional, and costly, digital framestore in addition to the normal analogtimebase corrector to do any "trick-play" operations, such as slow motion/variable-speed playback, frame step play, and visible shuttle functions. This was because, unlike1-inch type C which recorded one field perhelical scan track on the tape, Type B segmented eachfield to 5 or 6 tracks per field according to whether it was a 525- (NTSC) or 625- (PAL) line machine.[10]
The picture quality was excellent, and standard R/P machines, digital frame store machines, reel-to-reel portables, random access cart machines (for playback of short-form video material such astelevision commercials), and portable cart versions were marketed.[11][12]
Echo Science Corporation, a United States company, made units like a BCN 1 for the U.S. military for a short time in the 1970s. Echo Science models were Pilot 1, Echo 460, Pilot 260.[13][14][15]
Type B video Scanner HeadType B VTR, BCN 20 Tape Desk and video Scanner
BCN-100 (random access 32 multicassette machine, up to 16 hours rec/playback-20 min per tape) Each unit had 3 tape desks with a 21 sec load time each cart. For on air playback and 3 deck editing system[24][25][26]
Image Transform inUniversal City, co-founded by Ken Holland, in 1970,[35] used specially modified BCNs to record 24-frame video also, but for their "Image Vision" system. The BCN would record and play back 24-frame video at 10 MHz bandwidth, with 655-line resolution.[36] To record this the headwheel andcapstan ran at twice normal speed. Modified 24 frame/s 10 MHz Bosch Fernseh KCK-40professional video cameras were used on the set. This was a custom pre-HDTV video system. This Image Vision recording could then be recorded tofilm on a modified 3M Electron Beamfilm recorder (EBR). Image Transform had modified other gear for this process. The system was used to record "Monty Python Live at the Hollywood Bowl" in 1982. This was the first major use of early electronic cinema technology (using wideband high-resolution analog video technology, predatingIT-based DI (digital intermediate)post production for film nowadays) using a film recorder for Film out.Electronovision was also a pre-process like Image Vision. Merlin Engineering also worked on the BCN's wide bandwidth, 10 MHz, BCN modification.[37][38]
Bell and Howell (later Rank Video Services) used special BCNs for massVHS duplication. These specially-modified BCN VTRs could play back movies at two times the normal speed. In addition, the sync signals were also at two times speed as well. For proper playback, the headwheel and capstan also ran at twice normal speed. Specially modified VHSrecorders could record thisvideo. In doing this, the duplicationplant could output twice the product than normal videocassette duplicating systems.[39][40][41]
Bell and Howell's Data Tape division inPasadena, California modified BCNs to record high speeddata forinstrumentation purposes. These instrumentation recordings were mostly used by US government agencies, such as forNASA on theSpace Shuttle. This unit could record data from up to 800 sensors.[42][43][44]
Some users modified BCNs to fit 2-hour reels of tape on the BCN, so complete 2-hour movies could fit on one reel of tape. Bosch later made this a factory option, and was designated as BCN LP.
Bosch also offered SLP BCN, a "long-play" variant of the format. It moved the tape at 1/3 speed so that up to 6 hours could be recorded one reel. The unit has a specialhead wheel withazimuth head. This was mostly used fortime zone tape delay by television networks. With a head wheel change and a switch the unit could be returned to normal play.
Between 1977 and 1980 the UK Independent Broadcasting Authority (IBA) experimented with a B format machine as part of their researches into digital video broadcasting standards. In April 1980 a machine was exhibited at a meeting of the EBU Technical Committee in London as part of a complete digital studio system based on a proposed video standard based on YUV 12.4.4. The machine is described in a paper in the IBA Technical Review of March 1982 which can be found here[46] by scrolling down to the item IBA_TechnicalReviews1-24""
One of the firstDigitalSDTVVTRs was a non-productionprototype BCN deck that could record and play back early type ofCCIR 601digital signals. These three Bosch VTRs paved the way for the laterSMPTED1 VTR standard. In 1985 and 1986 in aRennes experimental digital studio inFrance, an experimental all-digital television center was made, it used the two all digital BCN units.[47][48][49]
^Oscar Technical Achievement Award, Bill Hogan (II) (Ruxton, Ltd); Richard J. Stumpf (Universal City Studios' Production Sound Department); Daniel R. Brewer (Universal City Studios' Production Sound Department)- For the engineering of a 24-frame color video system.
^imdb.com Academy Awards, Technical Achievement Award, Bill Hogan (II) (Ruxton, Ltd), March 29, 1982, Los Angeles, California
^NewBay Media The Top Guns of Digital Intermediate, January 28, 2004, Ken Holland
^Gregory, Lee (January 1983). "ImageVision Meets Monty Python Live at the Hollywood Bowl".American Cinematographer.64.
^epatents.gov SYSTEM FOR DUPLICATING INFORMATION RECORDED IN SLANTED TRACKS, RANK VIDEO SERVICES AMERICA
^audiosystemsgroup.com Page 129, CONSUMER VIDEO TAPE DUPLICATION TECHNIQUES, A TUTORIAL, by Jim Brown, SOUND ENGINEERING ASSOCIATESCHICAGO, ILL., CONSULTANTS TO BELL AND HOWELL/COLUMBIA PICTURES VIDEO SERVICES
