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TBC question: macrovision removal?
K, so I did as others have suggested and incorporated a professional rackmounted TBC (time base corrector) to my home broadcasting rig. Trouble is I still have macrovision in my vintage sets, and I thought a TBC was supposed to cure that. It's a FOR A FA-310 model, and it seem to be in working order. All the pots behind the front panel (like chroma phase and background) work like they should, even freeze frame works like it's supposed to. Any reason a high end TBC wouldn't remove macrovision? Have I blown $100 for nothing here?
More on the rest of the rig later, that's a separate post.
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#2
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Could be that it does not replace or adequately clean the vertical synch where the crap lies...I've got a few consumer TBCs that make tape look good (the main design objective of a TBC), but won't touch macro-vision....
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
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http://www.ebay.com/itm/For-a-FA-310...item4184a68490 I'm at a loss, I just wanna watch a damn movie!
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#4
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I have a 1997 movie on VHS called 'HOUSE ARREST' that has this crap and the video looks NOT AS GOOD AS IF IT DIDNT HAVE THIS GARBAGE!!!!! Does anyone know how to remove it?? (W/o using anything DIGITAL to do it) |
#5
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Score one of the "stereo" RF modulators sold by Radioshack between 2000 and 2003. Somehow they more or less blatantly ignore macrovision. |
Audiokarma |
#6
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Back in 2001 or so I bought 3 "Stereo 2000" modulators on clearance at RS. Is that the one? Only MTS Stereo modulator I recall ever seeing for sale at RS.
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https://www.youtube.com/watch?v=jk0wDG_bZwc |
#8
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Do you have a link to a manual for your TBC? (Now looks like no.) Does it have a white clip adjustment? Adjustment for which vertical interval lines are blanked? (I may be remembering BetaSP VTRs rather than TBCs on the blanking.)
(Remarkably, the one on koppix.net has one for a buy-it-now price of $11.) Chip Last edited by Chip Chester; 12-15-2014 at 09:46 PM. |
#9
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TBC manufacturers are understandably a bit reluctant to say whether their products will strip Macrovision. In practice I understand that industrial/professional TBCs will do this. They will certainly insert new blanking and syncs.
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#10
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I don't see a white clip pot on the front panel, but it may be an internal adjustment. Won't know unless I can come up with a manual. I guess I still need a macrovision stripper.
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Evolution... |
Audiokarma |
#11
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The problem is visibility in retrace; a white clip may reduce it, but will not eliminate it. The offending pulses need to be replaced with blanking level.
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#12
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It was my understanding (from long ago...) that the macrovision signal in the vertical interval went significantly over 100% in order to provoke the automatic gain control and get their desired effect. There are several 'normal' signals that exist in the vertical interval -- closed-captioning, vertical-interval timecode, vertical-interval test signals, and Neilsen data among them. They all are "allowed" up to 100%, so a macrovision signal limited by clipping to 100% shouldn't cause gain control problems. Have I actually tried this to defeat macrovision? Nope, never had the cause, or time, to do so. So if others actually have tried it, with a tweakable tbc monitored by a scope, I'll of course defer to their direct experience. But I do know that VITS, the vertical-interval test signal, often uses a one line of full 100% colorbars to do its business. So if a auto-level control can handle one line of full level in the VBI, I would think it could handle five (or whatever) if clipped to 100%.
I recall hearing at the time that RF out from the playback deck, routed to RF in of the record deck, was a way to evade the issue. Quality would be not-so-great, though. I do know many small broadcast switchers totally rebuilt the VBI, as well as pro TBCs or frame synchs, because they would be the first place to look when closed-caption data was being mistakenly stripped from a known-good captioned source. A switcher or effects box that will do a simple wipe will also take care of the matter. Looking at the macrovision wiki reveals folks that have been sued or absorbed due to their success in defeating macrovision. That would be the beginning of my search for a solution on the used gear market. Good luck! Chip |
#13
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Sorry I don't know all the techno stuff about this but I do know that I bought one of these off that auction site and it works awesome!! The picture is free of that macro nonsense and crystal clear.
http://www.ebay.com/itm/Digital-Vide...item2a479e1918 Gregb |
#14
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I recall there was a Hitachi-made GE VCR top-loader model early '80s that would blank out all the copyguard and other stuff in the vertical interval, even with E-E signals passed through its Video input, so it would be gone when playing back on one of their TVs with the Vertical Interval Reference "VIR" automatic picture control. Seems the wow and flutter time base errors added to the tape playback caused havoc with the TV's VIR working properly, so they just stripped it from the video through that VCR. The mechanically similar Hitachi branded model did not have that.
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#15
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