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12-02-2010, 03:40 PM
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deter deter is offline
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This is a weird question, often wondered the answer.....

- How do studios produce so many copies of a VHS tape...
- How do they record what is on the tape.
- What are they usings for the source playblack.... Aka TV show, something shot on Film.....
- What are they using for recording......what type of machine...
- Do they make a master copy than go to mass production...
- How would the encode the macrovision in the tape.. (granted Macrovision tends to degrade the quality of the picture big time)

In house I have maybe 20 tapes of the same title. When u watch them, they are pretty much the same. They don't play that much different than the next.

A store purchased VHS tape is normally a higher quality recording than something u record off the TV.
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  #2  
12-02-2010, 04:26 PM
NJRoadfan NJRoadfan is offline
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The duplication is usually done with a bank of dedicated industrial duplicator VTRs. The tapes are fed in using automatic tape changers. Macrovision is likely encoded on the spot, the pro VTRs usually don't have any AGC circuitry which Macrovision targets. The source video is likely a high quality format like Betacam SP, and later on, any digital format. Wouldn't be surprised if 1" Type C reel to reel saw use in the 70s and 80s as well. The VHS tapes commercial recordings come on are usually lower quality though.
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12-02-2010, 05:00 PM
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Most production is -- or rather was, at this late date -- from a signal served by a non-VHS broadcast/duplication master. There's realtime methods, and non-realtime methods.

The Masters:

Broadcast/dupe masters are typically U-matic (oldest), D-1, D-2, or Digital Betacam (Digibeta) versions of the edited film. It really wasn't until the DVD generation (2000s) that you had 2K and 4K film scans down-processed to DVD-Video specs via software, sometimes cleaned/filtered, and then encoded out to the MPEG-2 files. In other words, video output that's closer to the original sources.

These days, D-1/D-2/Digibeta has been replaced by formats like MXF or DVCPRO50 (both of which I'm encoding from right now on the next machine over!). And then film itself has been supplanted by P2 and various 2K/4K formats.
HD = 1920x1080p or 1280×720p
2K = 2048×1080p
4K = 4096×2160p

Even Betacam SP is a rather low-budget grade of format, mostly used by news stations and indy studios. The lower budget modern alternate is HDV or DV (non-Pro).

There were rival formats from Panasonic, such as D-3 and MII, too. (The "D-3" was sneaky marketing, as it was not an upgrade to D-2, but rather a different format entirely that competed with D-2. Reminds me of DVD-R vs DVD+R. It plays on social engineering.)

Realtime:

The realtime method was used by smaller post houses, cable/college facilities, etc.

The master signal was then further processed to SD, genlocked and timebase corrected, within various processors -- often simply high grade multi-function TBCs. A distribution amp (or "splitter" to the layman) would feed the signal into racks of VTRs. VTR = video tape recorder, which isn't really the same as a VCR. A VTR lacks tuners, generally only recorded in SP mode, etc. Most of these were controlled by a central console of some kind. It was a turnkey system, but required human interaction to load/unload the tape decks, initiate the next batch, etc.

Cheaper low-budget productions often used professional VCRs and recorded in LP or SLP/EP modes. These are the tapes from the dollar stores, flea markets, etc. Sadly, that is how quite a bit of animation was released in the 80s and early 90s, both licensed and public domain works. Only bootleggers used home consumer VCRs -- even the crappiest low budget operation used professional decks. I would note, however, that the low budget nature of the operation would generally abuse the machines, running them without cleaning or maintenance, and well beyond their expiration.

Non-realtime:

There are thermal-magnetic contact transfer systems that can create a tape in under a minute, with high speed processing. For example, Otari systems: http://www.otari.com/support/vintage/t710/index.html

For this, a VHS master had to be created first -- likely on a special material.

Several companies had patents on thermomagnetic contact duplication, such as Xerox and Dupont. The attached PDF is the Dupont patent. And then here's an article on the "new" technology, circa 1988:
DupontArticle-NewScientist1988.jpg

Who Made What?

As far as who used what to make what ... I have no idea. I wouldn't be able to tell you which commercial video tapes were made with which method, and from which source. Given the rather sorry state of video industry record-keeping, I doubt anybody will remember which tapes were made with which methods, save a few retired or aging employees from dub facilities.

I didn't really enter video until the end of the 1990s, as most of this technology was already dying and being replaced. My interest was heavily into digital restoration of older sources, and not the production of it.


Attached Files
File Type: pdf Dupont TMD Patent US4698701.pdf (415.7 KB, 2 downloads)

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  #4  
12-02-2010, 05:24 PM
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Here's a newsgroup post from earlier this year, with a first-hand account of the duplication business. It's sort of a quickie history lesson specifically about high-speed duplication of video tapes.

Quote:
Like a photographic processing, high-speed video duplication is basically a printing process except instead of light passing through a negative onto a paper, a 700 to 800 oersted blank tape and a 2400-2600 orested high energy master are in intimate contact and passing through an high energy field that is strong enough to provide an erase bias for the copy tape, but not enough to degrade the master the master due to the tremendous bias need for a 2600 orested tape. Traveling out of the bias field, at 150 IPS, the copy tape would be immediately cloned by the master in a direct magnetization transfer printing process as the master pressed each copy tape around each individual slave copy drum at 6 different points simultaneously along the master path.

As Chris Hill said, a specially modified AVR-1 was used to make the high energy mirror masters as they were called. NET had 2 stock AVR-1s in house and either one could be quickly switched over to make high speed masters. The change consisted of exchanging out the bias erase head, corresponding driver circuit board and the same for the video head. Both heads and circuitry were beefed up to handle the extra bias and record energy needed. The erase stack had to be liquid cooled and Spin Physics modified the video heads to spin in reverse, hence being able to create a mirror image. The left to right master prints right to left copy.

A high-speed 10x transferred copy tape was about 3db down from a perfect real-time duplicated copy, however it's uniformity and almost perfect interchange statistically yielded more acceptable copies than the up to 50 or so individual VTRs needed to produce the same amount of production capacity. (depends upon how fast operator can switch out tapes) The masters could theoretically last forever, as far as energy levels needed, however in time the master would become dirty and loose intimate contact, yielding further gradual signal db loss. Many masters were recorded over and used again as different program masters. Many times, masters would catastrophically fail before their average number of uses would cause failure. Once a tape became wrinkled or creased, it could no longer be used. It could be shortened to a shorter master length, but only if the crease was close to either end of the tape. It had to be that much shorter. Many real-time Quad tapes were spliced, due to the almost perpendicular head path, but the ADR-150 had extremely low thickness tolerances so splices meant certain death of a master or copy.

Our ADR-150 was about 25 ft long by 6 ft wide by 3 ft high. The master would run down one side of the machine, past 3 slave copy stations, then return back passing another 3 stations on it's way back to the master station take-up reel. Each of the 6 copy stations had 4 AVR-1 type vacuum columns yielding 24 Air vacuum chambers to buffer the movements of 6 individual copy tapes in intimate contact with a master at 6 different 10" rotating copy drums along the master tape path. Each copy drum had 2 separate air knives along a drum collar to assure intimate contact. along 270 degrees of the rotating drum. The master would then automatically rewind while the operator changed out the 6 copy stations with more tapes and then re-started the process.

Yes indeed, I loved to run and work on that machine except for the fact that you had to wear earmuffs because it sounded like you were on the tarmac of an international airport. IT WAS VERY LOUD !!!! It blew and sucked more air than anything I've ever worked. Extreme care had to be given to operating and maintaining this electromechanical beast. If any one of the numerous servos fell out of balance, as the 6 slaves chased the master traveling 12.5 ft/sec (8.5 mph), or any moisture entered the system, or any vacuum loss in any one of the 24 columns, or any over pinching of the air knives, there would be a traveling pileup of tape loops and creased tape. The operator would witness something like a chain reaction of car accidents traveling first down the highway, then turning around and traveling back up the highway.

In the 1980s, Sony manufactured a high-speed 1/2 duplicator called the Sprinter 5000. (S-printer) It was first designed for Beta and then Sony sadly converted it to VHS. This machine had just one station and ran at 16.6 ft/sec. Later, a new model 800 was introduced with a endless master loop that vibrated on a horizontal loop bin, much like those vibrating football game tables of the 1050s. It's speed was then almost doubled to 8 meters/sec and it's effective duplication speed was increased to almost 240x for SP and 720x for EP VHS. I built a facility for Allied Film & Video in the 1980s that housed 16 of these machines and also developed an endless master bin for the first 5000 Sprinter.

In the late 1980s, Otari took over a joint research project started by Dupont and Bell & Howell to develop the TMD. (Thermo Magnetic Duplicator) Dupont wanted to sell chromium and Bell & Howell owned several large VHS duplication facilities in Chicago at the time. They later became Rank and moved much of the operations to Little Rock, AR. The technology was similar in mechanics and magnetic printing process, however instead of using a bias field to erase iron tape, a laser was used to heat chrome tape to Curie point and erase the tape. Chrome tape needed a much lower temperature to accomplish this and the quality was quite good. Otari had 2 problems besides being late in the game. Chrome tape was more expensive and their loop bin was vertical instead of horizontal. This meant the weight of longer movie masters meaning more tape could crease the tape, where as horizontal loop bins didn't have this problem. However, by the time Otari had a competitive product out in the field, Sony had almost saturated the VHS high-speed duplication business as VHS was reaching maturity.

While Bell & Howell started as the largest duplicator, Technicolor later became the largest US and then worldly duplicator. Both companies started with 10s of thousands of real-time duplicators. B&H/Rank first implemented 2x machines using large pancakes of blank tape that were later cut into separate video cassettes like Sprinters and TMDs. Then Panasonic made a 2X in cassette duplicator especially for Rank then later other smaller competitors and Technicolor later introduced their own 3x in cassette duplicator. Cinram followed as well with a 2x in house design.

Technicolor became the king with the most Sprinter duplicators boasting around 80 unites between Livonia, MI and Camarillo, CA and more around the world. The largest Sprinter installation ever was a facility I designed and built in Alphaville, Brazil in suburban Sao Paulo, where Videolar had over 100 Sprinters in one very large clean room. High-speed duplication at one time was at least 50% of the movie business of which probably 80 to 90% was Sony's Sprinter. Oh yes, all good high speed operations were typically conducted in class 1,000 or better rooms. As time went on, the vendors advertised class 10,000 in order to sell more product. You need massive amounts of properly directed air flow (we had 3 air changes per minute) and lots of 0.1 to 0. 5 micron HEPA filters.

Finally, let's talk about cleanliness in Quad vs. VHS when it come to high-speed duplication. As you know, it is a contact printing technology so cleanliness affects transfer quality. One second of Quad time represent 2" times 15" per sec. tape speed yielding 30 square inches of magnetic information describing 1 second of video. Whereas 1 second of VHS tape time represents 1/2" times 1.3" per sec. tape speed yielding 0.65 square inches of magnetic information describing 1 second of VHS SP. AND one 1/3 that or less than 0.22 square inches of tape for VHS EP. Cleanliness and intimate contact are far more important when you have around 1/50th and 1/150th respectively less real estate to work with.
I've heard the name Cinram a few times through the years. They do quite a bit of large-volume audio and video duplication on pressed DVD-ROM and CD-ROM. And then ISO certified cleanroom status never occurred to me -- but it makes sense.

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  #5  
12-02-2010, 05:32 PM
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This looks like it will also make for a good read...


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File Type: pdf AESConsumerVideotapeDup.pdf (1.29 MB, 10 downloads)

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  #6  
04-01-2023, 05:22 AM
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I just love this thread ! ! I always wondered how they did these tapes, because i have a couple ones (late 90's) that are pristine. Now I'm dreaming of a home TMD machine but i'm dreaming i know. They don't talk about cost but pretty sure it was in the 100-300k ballpark. Amazing tech
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04-01-2023, 06:21 AM
latreche34 latreche34 is offline
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What I don't understand is how HiFi audio is printed, It's recorded in a deep layer under the video, If the master contacting the blank tape it would only transfer the top layer which is video, Or do they have two masters one for audio and one for video and they repeat the process twice, But timing the audio to the video at a field level will be dificult.

https://www.youtube.com/@Capturing-Memories/videos
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04-01-2023, 07:12 AM
timtape timtape is offline
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I agree that if they had to be done in two passes the time alignment would have been very difficult.

As I understand it, by definition low frequencies magnetize deeper into the oxide layer. The higher the high frequencies, the less they penetrate and the more they are confined to the surface layer of the oxide layer.

So in the high speed duplication method described I assume all frequencies were effectively recorded in the same way as normal, with the lower frequencies going deeper and the higher frequencies shallower into the oxide layer. So it could all be accomplished in one pass, as with normal audio and video recording.
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