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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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12th Mar 2020, 12:10 pm | #41 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,184
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Re: VHS was a phenomenal achievement!
Does that apply to 4 head machines as well? I always assumed two of those heads were normal sized.
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12th Mar 2020, 4:14 pm | #42 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
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Re: VHS was a phenomenal achievement!
HQ was introduced at Hollywood's behest, as a front to ensure machines were (in?)compatible with MacroVision. To the unaware consuming public, it looked like "High Quality"; but in reality, it was simply a tightening of tolerances (and in some cases alteration of circuit topology) to ensure that the machine's video AGC would respond to noise in the vertical blanking interval between frames.
Most non-HQ recorders, by accident or sometimes by design (there must have been at least one manufacturer who deliberately gated-out the blanking intervals, just on the principle of "the wider you open the window, the more unwanted stuff comes in"), would make watchable copies of MacroVision-encumbered cassettes. Of course the project was ultimately a spectacular failure anyway, since it was still trivially easy to defeat (indeed at first, it was assumed that the noise during the vertical flyback period was just an unfortunate artefact of a new mass-duplication process, as opposed to deliberate sabotage; either way, the brave Robin Hoods fighting the greedy Hollywood studios found a way to deal with it as usual, because a working copy-prevention scheme would require the same statement to be both true and false). But the MacroVision corporation ended up doing quite well out of the deal. As, no doubt, did Arizona Microchip and the manufacturers of ICs such as the LM1881 and HEF4066BE! By the way, many DVD recorders have a built-in MacroVision repair facility. You just need to put the machine into RECORD PAUSE with a "clean" video signal already present on the input, then quickly switch over the input to the "dirty" signal. They only show "COPY PROT" and sulk if the first video signal seen is MacroVision-encumbered. Evidently at least some of the people who designed DVD recorder chipsets didn't like the idea of paying again for movies they already owned!
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If I have seen further than others, it is because I was standing on a pile of failed experiments. |
12th Mar 2020, 5:09 pm | #43 |
Dekatron
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,549
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Re: VHS was a phenomenal achievement!
I had a look at Macrovision many years ago and ended up with a circuit diagram with a 4066 and a pot to set the AGC on the VCR to give a kind of record contrast control.
I never got round to building one though. I have not seen the drawing for years. |
13th Mar 2020, 12:00 am | #44 |
Octode
Join Date: Jul 2014
Location: Petersfield, Hampshire, UK.
Posts: 1,043
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Re: VHS was a phenomenal achievement!
The first generation of ENG used a 3 tube Sony camera (£30k) ( model no BVP 330 ) coupled via a multiway cable to a U matic Hi Band recorder (£3k ) ( BVU 50 ) .
It used a smaller tape which ran for 20 mins. There was also a portable player /recorder £7k ( BVU 110 ) for playback in the field for viewing the rushes and feeding back to base using a TBC ( time base corrector ) The bigger edit machines (£ 20 k )could handle both these small and the larger 60 min tapes . Heavy gear but we were young ! Cheers Pete |
13th Mar 2020, 6:19 pm | #45 | ||
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,951
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Re: VHS was a phenomenal achievement!
Quote:
I always loved that ad - though (as previously mentioned) not many of my relatives/acquaintances/workmates actually used VHS for off-air recording - we were much more into bought/rented movies, never-broadcast-in-the-UK cartoon-series etc. [Someone out there still has my VHS tape of "Die Hard" for which I paid half-a-week's-earnings to acquire only a day after the movie was first released to movie-theatres. I lent it to them and they never returned it. Grrrr!!!] |
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