Macrovision question

[RennMax]

Hello,

I have a question regarding commercial VHS duplication and anti-copy tech - specifically Macrovision.

Does anyone one know how MV's 'manufacturers' delivered it to duplication houses? Was there a piece of hardware, an add-on of some sort that generated the MV signal or was it provided as a recording on some sort of storage of it's own?

I'm guessing it was the former - some sort of signal generator that ran side by side with the master tape?

Any details or thoughts will be much appreciated.

G

[dvd3500]

Seen this?
https://www.youtube.com/watch?v=-VqsU1VK3mU

[lordsmurf]

generated the MV signal or was it provided as a recording on some sort of storage of it's own?
- some sort of signal generator that ran side by side with the master tape?

Retail tapes were not recorded.
The tapes were duplicated.
Some years ago, there was a good thread on it here at VH.

Seen this?
https://www.youtube.com/watch?v=-VqsU1VK3mU

That guy has proven himself to be f'ing moron multiple times, so his info is therefore ALWAYS suspect. He's just some millennial Youtube asshat, not a qualified resource for video topics. You may actually get dumber by listening to his mind vomit.

[RennMax]

Thanks for the replies.

Yes, I've been reading a bit about duplication and it's various techniques. I found this thread here the other day, maybe it's the one you are referring to?

http://www.digitalfaq.com/forum/video-capture/2613-store-purchased-rented.html

Fascinating stuff - and there's info around on the net regarding the Sony Sprinter and the Otari system.

http://www.digitrakcom.com/TechDocs/SONYsprinter.pdf

http://www.otari.com/support/vintage/t710/index.html

But if you were operating one of these machines in the 90s to run off a two thousand VHS units of a mainstream feature with added MV - how do you think the anti-copy signal entered the workflow?

I've seen some of his videos - aren't you being a bit harsh? : )

[mike20021969]

Seen this?
https://www.youtube.com/watch?v=-VqsU1VK3mU

That guy has proven himself to be f'ing moron multiple times, so his info is therefore ALWAYS suspect. He's just some millennial Youtube asshat, not a qualified resource for video topics. You may actually get dumber by listening to his mind vomit.

I imagine you've watched the video. Give us a run down on everything that's wrong with it... what information is "suspect"?

[lordsmurf]

Yes, I've been reading a bit about duplication and it's various techniques. I found this thread here the other day, maybe it's the one you are referring to?
http://www.digitalfaq.com/forum/video-capture/2613-store-purchased-rented.html

Ah, yeah, that's it.

"contact transfer", I could not remember the term. (At this late date, it's mostly trivia.)

But if you were operating one of these machines in the 90s to run off a two thousand VHS units of a mainstream feature with added MV - how do you think the anti-copy signal entered the workflow?

It was likely mastered into the signal, not too different from DVD anti-copy. I never did analog, but I did have to deal with it on DVD-R(A) masters.

I've seen some of his videos - aren't you being a bit harsh? : )

No. I'm anti-myth, anti-disinformation, and anti-BS in general. When I don't know something, I say "I don't know" (and I actually say it quite often). Better yet, just stay quiet (my preferred modus operandi). Or I'll outright state that a statement is my hypothesis/guess (usually educated guess). I don't just mind vomit and pretend to be an expert on the subject. That guy's weasel terms are a tell-tale.

I actually don't mind hypothesis/guessing when the data is unknown (proprietary, behind NDA, lost, etc). But that's not what this guy does. He just does not do proper or adequate research. Several of his videos have been shredded on this site and others, revealed as the nonsense it is.

I wouldn't be so "harsh" if he wasn't a totally dismissive ass when confronted.

Give us a run down on everything that's wrong with it... what information is "suspect"?

It's hard to even know where to begin.

However, he uses a lot of weasel terms:
- I think
- it seems
- probably

It's obvious that his grasp of the concept is tenuous at best. The result is, as is often the case in his other video-topic videos, a mishmash of true and false information.

One of the bigger problems, in all of his videos, is that he's using garbage hardware. I can only guess these came from Goodwilll or somewhere. There are so many errors to the point that it skews his observed data.

The more the video blabs on, the more fubar the information gets, to the point of being pulled-from-ass disinformation.

[lingyi]

Edit: Sorry didn't see the same link in the OP's reply.

@ls

IIRC, pro machines had adjustable AGC, which seems like an oxymoron. But Wiki also states that there may also be a TBC on the input. Is that correct? I thought an external TBC was (almost) always used between pro machines.

As discussed in this thread, large production commercial pre-recorded tapes were created by high speed contact duplication machines like this and small scale productions by realtime duplication. An indication that the tape is made by high contact duplication is that there will be little to no extra tape on the feed spool since the tape is custom spooled on the reel vs the preset length (usually in 10-15 minute intervals, e.g. T-20, T-90, T-105, etc.) found on VCR to VCR duplicated tapes.

The Macrovision signal is probably mastered into the master and the AGC on the duplication machines adjusted to ignore the signal. As discussed in another thread, most Sony Betamax machines, because of the different type of AGC circuitry and the way the recorded signal in Beta is handled, ignored most types of Macrovision. IIRC, some/most? professional VCRs also ignored Macrovision.

Note that the Macrovision is ignored, not removed. The signal is still there in the VBI.

[lordsmurf]

@ls
IIRC, pro machines had adjustable AGC, which seems like an oxymoron.

Substitute the word "adjustable" for "calibratable", and that's really it. Since "calibratable" isn't a word, perhaps that's why "adjustable" was used? Misleading? I've never really heard of adjustable AGC (automatic gain control), but I do know it can be calibrated.

But Wiki also states that there may also be a TBC on the input. Is that correct? I thought an external TBC was (almost) always used between pro machines.

That doesn't sound right. Genlock, maybe? Again, as always, TBC is a loose term, and is often used liberally, or even wrong. Even the consumer TBCs we use, what I refer to as a "true TBC" in those terms, is just a kind of TBC, and with kinds of properties that we need for the kinds of sources.

As discussed in this thread, large production commercial pre-recorded tapes were created by high speed contact duplication machines like this and small scale productions by realtime duplication. An indication that the tape is made by high contact duplication is that there will be little to no extra tape on the feed spool since the tape is custom spooled on the reel vs the preset length (usually in 10-15 minute intervals, e.g. T-20, T-90, T-105, etc.) found on VCR to VCR duplicated tapes.

I sometimes wonder about EP distributions. Some were clearly recorded, but others were possibly run off of contact duplicators that were past their prime? I knew more about this stuff in the 1990s, memory gets hazy on some of this trivial/historical stuff that doesn't matter much anymore.

IIRC, some/most? professional VCRs also ignored Macrovision.

That's really a misnomer. It wasn't "ignored", which has the connotation of intention. These machines simply did not recognize it, and it was just a minor speedbump for the VTR processing video. Not much different than you stepping on a bug walking down the sidewalk in the dark. Totally oblivious. (It really reminds me of many people in regard to COVID-19. Some folks truly have no idea what is happening in the world right now, and/or don't seem to care.)

[RennMax]

I had a thought. As the anti-copy signal was a security measure to protect the studio/production company's product might they have aimed to install it as early as possible - perhaps even during the telecine process?

This would mean that the VT masters sent to duplication facilities had the signal baked in - reducing possibilities for error, need for quality control (of the anti-copy signal) and of course illicit copying from an unprotected master?

I've no evidence for this - just a guess.

[lingyi]

Memories from the past.

Sometimes partial runs of prerecorded tapes were released without Macrovision because someone forgot to flip the switch on the blackbox embedding the signal. Also, sometimes it was only included on the VHS and not Beta because of the smaller number of copies and Sony machines (who was the only manufacturer towards the end) largely ignored the signal. Use of Macrovision (and CSS for DVDs) requires an expensive license fee and I believe a per title fee which is why low-budget and foreign releases, tape and disk often don't use it.

Here's an excerpt from a book that goes into detail about tape and DVD copy protection: https://books.google.com/books?id=vMQqBgAAQBAJ&pg=PA122&lpg=PA122&dq=css+license+fee&s...%20fee&f=false

There's no sense in adding the signal to the videotape master as the TBC will strip and regenerate the VBI signal anyway. Which is why TBCs are recommended as the best way to defeat Macrovision then and now. I talked in another thread about how the black box I had would just slow, but not remove the Macrovision signal. Causing the copy to "pulse" much slower, giving a watchable copy.

[RennMax]

"There's no sense in adding the signal to the videotape master as the TBC will strip and regenerate the VBI signal anyway."

Good point - I guess that ends my added during telecine theory.



"Sometimes partial runs of prerecorded tapes were released without Macrovision because someone forgot to flip the switch on the blackbox embedding the signal."

Interesting - but it brings me back to my original question - what form did the 'black box' take?



"An indication that the tape is made by high contact duplication is that there will be little to no extra tape on the feed spool since the tape is custom spooled on the reel"

I'd never thought of this before but it makes perfect sense - much thanks!


Is there anything other information in addition to the above that can be gather about the production of a commercial tape from inspecting it today.

Using the above one could tell if it was recorded or duped and whether the operative responsible for the anti-copy may have been dozing!

Does anyone know what purpose the DTMF signals often heard at the start and end of a recording served?

[lordsmurf]

I had a thought. As the anti-copy signal was a security measure to protect the studio/production company's product might they have aimed to install it as early as possible - perhaps even during the telecine process?
This would mean that the VT masters sent to duplication facilities had the signal baked in - reducing possibilities for error, need for quality control (of the anti-copy signal) and of course illicit copying from an unprotected master?

I don't recall VHS mastering really being any different from DVD mastering, and anti-copy was injected well in advance of the pressing. That was two separate processes, much like encoding and authoring (something video novices have a hard time understanding, no thanks to all-in-one/dummy software). With DVD, it was part of the DLT / glass mastering stage, post-authoring workflow. The actual duplication was a job for interns or less/un-educated labor. That actual duplication step didn't require a degree, and was simply a trade (or even monkey-see-monkey-do sort of task). It was a mechanical process. Though surely overseen by somebody with video knowledge, some sort of supervisor, in case anything went sideways in the batch. Which did happen.

Use of Macrovision (and CSS for DVDs) requires an expensive license fee

It did, especially after it became a de facto monopoly.
People often consider all forms of copy protection to be "Macrovision", but it's not. Not anymore than copying a document was "Xeroxing" it (often heard, back in the day).

There's no sense in adding the signal to the videotape master

The problem with that statement is that there is never a single master of anything. There are "masters", plural, for different purposes. For example, broadcast masters vs. home market duplication masters vs. rental market masters (though those latter two did seem to merge in the 90s). And when each master was made, duplicate masters were as well. Many people assume "master" is the source, but there are pre-mastering stages with raw(er) footage. Those assets are assembled for masters, and reassembled for other masters. And sometimes masters are used to make new masters (and no, those are not duplicates, nor really consider latter gens due to QC in these super-quality formats).

Confused yet?

This may help: https://www.youtube.com/watch?v=S7blkui3nQc

as the TBC will strip and regenerate the VBI signal anyway. Which is why TBCs are recommended as the best way to defeat Macrovision then and now. I talked in another thread about how the black box I had would just slow, but not remove the Macrovision signal. Causing the copy to "pulse" much slower, giving a watchable copy.

That's exactly it. Those cheap sub-$25 black boxes implored tricks to make it "work", but with image degradations.

To truly remove the artificial errors (anti-copy), as well as legit errors naturally occurring in the video signal, TBC is required. For this conversation, specifically, a framesync TBC that is designed for consumer sources (most DataVideo, most Cypress, though not all). Removal should be transparent to the source, or an improvement. Those POS "clarifier" boxes were not at all transparent. (Transparency is actually the main aspect that makes or breaks a TBC. For example, this is why Big Voodoo TBCs are crap, horrible transparency, or rather lack thereof.)

As I often have to say (to others, no you lingyi): Do you think I'd own expensive TBCs for fun? Seriously? I eat generic store-brand cereal to save a buck. If I could get by with a cheap DVD recorder, or some tiny magic box, don't you think I'd be doing it? Furthermore, while I have to keep my TBCs, others have the luxury of buying it, using it, and reselling it. So it's a recoupable temporary cost. Video is a hobby, even if temporary and project-based, and all hobbies have costs. Video can actually be one of the cheaper hobbies, compared to cars or cameras, or even action figures. Not many hobbies have a mere $1.5k price point to be "fully loaded" with everything needed.

My brain hurts trying to remember stuff from the 90s, keep having to re-edit the post.

[lingyi]

@lordsmurf

I always get a chuckle when you give me a little slap and correct my statements, and as always bow down to his lordship! I always forget and appreciate your correction about the use of "master". I think "production master" would be the correct term? Always appreciate that you're here to keep the facts straight and lingyi on the right path!

I'm happy that right now it's just you and I here. I'm sadly waiting for someone else to join this thread and post, "But, but..."something contrary to what you state from your years of experience and knowledge ala the Technology Connections guy." "But I read about it on the interwebs!" Yes, I'm talking about you, babygdev!

To be clear. I'm just an layman, but I know just a little more than the average person because I was a home video enthusiast in the 80's and 90's. Got my first Betamax in 1981 and owned some equipment, semi-pro VCRs, TBC, professional presentation monitor, that the average consumer wasn't even aware of.

@dvd3500

Not sure what you mean by what "form did the 'black box' take?". I suspect you're thinking that everything was done completely in the analog realm back then. It wasn't. The output of the Macrovision "black box" was analog, but the generation of the signal was digital within the box. Same with TBCs and other external video and audio processing boxes. *Waits for lordsmurf to correct me."

In the early 90's, my Dad brought home a black box that inserted "subliminal messages" that quickly flashed on the screen into the video signal. It sat between the antenna/cable or VCR input and the TV. My Dad thought it was some kind of amazing technological advancement (he was planning to sell them as part of a MLM scam), but I explained to him it was nothing new. I explained to him that it was just really quick closed captioning and showed him the VBI* (by using the vertical hold on the TV) to show where the signal was embedded.* I immediately noticed the flickering caused by the messages and thankfully he gave up on the idea of selling the boxes.

*IIRC, Closed Captioning is visible in the VBI as a black box or line.

Trivia: IIRC, a TBC will strip the closed captioning on a video signal.


As for testing for Macrovision, the easiest way to check for it is to use the vertical hold on a CRT TV to view the VBI. Macrovision and Copyguard are visible as something other than the normal black of a clean VBI.

Since HDTVs don't have a vertical hold, don't know if this would work, but you may be able to use an external processor box that a vertical hold adjustment. I used to have a Radio Shack detail enhancer that had one.


I don't know the details of why, but a badly formed VBI or one with non-Macrovision signals* may cause the capture device to falsely tag the video as containing Macrovision.

*From Wikipedia:

"In analog television systems the vertical blanking interval can be used for datacasting (to carry digital data), since nothing sent during the VBI is displayed on the screen; various test signals, time codes, closed captioning, teletext, CGMS-A copy-protection indicators, and various data encoded by the XDS protocol (e.g., the content ratings for V-chip use) and other digital data can be sent during this time period. In U.S. analog broadcast television, line 19 was reserved for a Ghost-canceling reference line 21 was reserved for captioning data. The obsolete Teletext service contemplated the use of line 22 for data transmission."

Source: https://en.wikipedia.org/wiki/Vertical_blanking_interval

[lingyi]

"Information on the master version of the video tape is encoded in the DTMF tone. The encoded tone provides information to automatic duplication machines, such as format, duration and volume levels, in order to replicate the original video as closely as possible."

Source: https://www.google.com/search?q=dtmf+tones+on+videotape&oq=dtmf+tones+on+videotape&aqs...hrome&ie=UTF-8

They can also sometimes be heard on radio and TV commercials as a signal for the start and stop time, either automatically or manually. Same concept as the little white circle on top right of old film movies. It was signal for the projectionist to switch the projector/reel in X number of minutes or seconds. A properly mastered (there's that word again! ) video transfer will edit or mask it out, but it's sometimes visible on budget or early video releases.

[lordsmurf]

Trivia: IIRC, a TBC will strip the closed captioning on a video signal.

That can happen. Depends on TBC type. The DataVideo TBC-1000 strips CC, from what I remember. I know there were a lot of CC conversations at VH years ago, by now-gone members like FulciLives participating (that I can remember offhand; it's sometimes strange things you can randomly remember).

I don't know the details of why, but a badly formed VBI or one with non-Macrovision signals* may cause the capture device to falsely tag the video as containing Macrovision.

Sometimes "why" doesn't matter as much as just acknowledging it exists. I probably knew why, and surely read why, and could probably even suggest a couple of video books where I last read explanations. But that info serves no purpose in my noggin's memory banks, and is not useful information for my current era tasks. Anybody trying to create a TBC should care, and maybe the folks on the ld-decode project, but that seems it to me.

[RennMax]

"Not sure what you mean by what "form did the 'black box' take?". I suspect you're thinking that everything was done completely in the analog realm back then. It wasn't. The output of the Macrovision "black box" was analog, but the generation of the signal was digital within the box. Same with TBCs and other external video and audio processing boxes."

My question is really just this - if it's mid 90s and I'm, for example, Warner Home Video and I send Macrovision a cheque to license me to protect my product with their system- what do they send to the dupe facility or wherever else the signal is introduced into the mix. What physical form did it take on delivery? A rack device?



"In the early 90's, my Dad brought home a black box that inserted "subliminal messages" that quickly flashed on the screen into the video signal. It sat between the antenna/cable or VCR input and the TV. My Dad thought it was some kind of amazing technological advancement (he was planning to sell them as part of a MLM scam), but I explained to him it was nothing new."

Wow - what was that called and is there any trace of it's history on the web?

https://www.americanradiohistory.com have an amazing archive of magazines that might have featured small ads for such ideas - any more info that could help track this down?

[lingyi]

First, the studios use duplication houses for their work [edit: I see you mentioned that]. Few, if any studios own their own duplication house for videotapes or optical discs. The studios have no control or interest in what the duplication houses use or purchase. If they don't show proof that they're using licensed encoders, they won't get the project.

Second, I can't find any images of one, but the encoder was probably a rack mount device. Nothing mysterious about it and I don't understand why you think it would be anything special.

Third, I have no idea of what the name of the box my had was called, but it was the size of a large cable box with most of the space being empty for cooloing. Again, like the macrovison encoder, nothing special about it. I vaguely recall recording the output from the box and the text being static instead of quickly flashing on and off. Probably because the VBI was out of spec for the recorder.

AFAIK, it was never on the open market. Just through some MLM, that my Dad and his friend were always trying to get in on.

Another memory from the past. There was a conspiracy theory in the '80's the government and TV broadcasters were hiding and transmitting secret messages in the VBI that could only be decoded by the receiver with the right equipment. The theory was based on some people noticing some additional visual differences in the VBI. Turns out it was the closed captioning signal which wasn't common back then.

Edit: AFAIK, there's nothing to prevent a duplication house from using the encoder without a license except the cost probably being included in the purchase price of the box. Again, nothing mysterious or nefarious. As I stated above, I believe a per title fee was required to use Macrovision on commercial releases, though there's probably nothing beyond the reputation and continued use of the duplication house to prevent it from being used without the fee.

[lingyi]

It seems you believe there's some super special agreement and high level control of the encoders between the studios and the duplicators. It's simply business. Duplicator, do you have the means and equipment to produce our tapes to our specifications? Do you have the equipment and license capable of the latest version of Macrovision. If Yes, we'll give you the project. If No, you won't get the project.

As I stated, it's not as if the studios are watching every step of the duplication process as evidenced by some batches of tapes being released without the protection. Another memory from the past. At one point, reports were that not all production runs of commercial tapes contained Macrovision, probably due to the licensing costs for using it. Sometimes only the initial run contained it, but later runs, especially when the release price was dropped, didn't.

The Macrovison videotape protection being analog was far, far weaker than the digital protection of CSS and beyond. Stronger protection schemes like the earlier CopyGuard were tried, but were too strong causing issues with direct playback on TVs. The huge number of Anti-Macrovision black boxes on the market, many of which, especially the cheaper ones didn't work, is proof of how easy it was to defeat.

[Cornucopia]

I'll tell you how it worked.

I know, because I worked for 3 years as lead duplication engineer at a semi-major dupe house in Dallas in the 90s. Semi-major, as the majors were the only ones that got a regular shot at blockbuster movie releases. But we got to do low-budget movie releases, tv shows (we did EVERY "Barney the Dinosaur" that came out in those days, to the point where I can still do the voice perfectly - I ran it THAT MANY times), instructional & promo videos, etc. Even got to do short runs of blockbuster movies that were still in final edit stage (at a nearby studio) and they needed window dubs to distribute to the producers & other benefactors.
During my shift, I ran the "head end", aka the edit suite where all the master tape decks were situated.

The "master tapes" - the duplication masters that we got, were usually only 1st or 2nd generation at most from the initial run of the "final edit master". Or it sometimes might actually be a 2nd pass output of an actual edit master, straight off the edit bay. What might make these different from other masters might be the inclusion of trailers - commercial or FBI warning disclaimers.
Any of the decent, self-respecting productions would always have Bars&Tone AND a countdown (which dips to black @ 2 seconds prior). That way, there would be consistent setup from one pass (run) of a dupe to the next.
Hardly any of them had what you refer to as DTMF tone - which is NOT what that really was. DTMF is the tone with overtones used in phones. What was on those tapes was an audio output setup calibration sequence, They never caught on at most places, because there was no single official standard.

The "head end" - consisted in those days of: multiple decks each of 1"C, BetaCam, BetaCamSP, 3/4" Umatic and UmaticSP, D1, D2, M2, VHS & SVHS, (Super) BetaMax & ED-Beta, 8mm/Hi-8. This was prior to the explosion of digital video (DV/DVcam/DVCpro, Digibeta, etc). All of it was SD, not HD. All of it ultimately output into the dupe feed as composite analog video. Every deck that COULD do genlock would be genlocked. Only the consumer formats (VHS, Beta, and 8mwm families) couldn't do that, and for those, they had to run through a (Harris?) digital framestore & sync box to enable their signals to play nicely with all the other decks. That box was a monster - bigger than a semi's engine! Genlocking allow us dupe engineers the ability to do live switching between decks, which we did often when the master might only be a 30min tape, and you needed to A/B switch decks multiple times to do a run of a 2 1/2 hour show.
The head-end also included a couple of everpresent and almost ALWAYS in-line TBCs of various brands, a closed-captioning reader & generator, various LTC+VITC reader/generator/sync boxes. Raw signal generators, a Chyron for creating downstream text overlays, a 2-layer DVE switcher (though we rarely had the opportunity to do fun/fancy stuff with it), Waveform generator+Vectorscopes, a few specialty boxes...and a Macrovision generator/inserter.

Our dupe hall - consisted of 2500+ VHS decks and hundred or so Betamax units. We had access to a SPrint high-speed contact printing machine, but they were very finicky, very complicated to setup & calibrate for each changeout, and VERY expensive to run, so they were only used when we did get the occasional blockbuster, where they would want to 20-50k batch job. Otherwise, it was REALTIME, VHS SP duping. Using, usually, Panasonic industrial frontload decks (sorry don't remember the model). BTW, changeout of tapes between passes was a lot of aggravation, but also a cause for one-up-manship and camaraderie - try going as fast as possible to get the most tapes changed (properly) in the ~2 minutes slated for the changeout! You develop a great ability to stack - at one point I could carry a stack of 80 tapes (only for 5-10 feet, but still!).

Custom decks - those industrial Pannys were retrofitted by inclusion of a circuit designed by our head engineer and installed by some of our engineering techs. It created a signal, injected into the stream (not the VBI, but still hidden), that not only allowed one to verify the location of duplication ("site" code), but also the deck it was run ("deck" code), and a timestamp. Plus, an ingenious little "cursive signature" that helped with authenticity, and it couldn't be duplicated, because it was so minute, it would degrade too much if copied. Our dupe house wasn't the only one to implement this type of process, but was certainly a leading participant. With it, we could trace where and when it was created and, by looking at the schedule, even who was the team that ran it.

Macrovision - it was a very simple 1U box, stuck in the top corner of the racks - because there were barely any controls to it and it was left on constantly. It was Macrovision-branded. It had genlock, input and output jacks, and that's it. It was a pass-through injector device that modified whatever ran through it. It included all of the multiple MV methodologies. It would have been setup in a run to be the last device in the patch chain prior to the distribution amp feed, when swtiched in (which was always a checkbox option for the producers, if they were willing to pay the additional licensing fees to use it - 80% of them did). No conspiracies, just corporate greed-originated IP protectionism, which many voluntarily jumped on the bandwagon. My understanding is that those boxes were never bought, but were LEASED from Macrovision. Thus if they were ever ending a contract, or if the dupe house ended business, had a fire, or anything else, the machine would have to be delivered back to MV. Which is why you don't see any out in the wild now.

Hope that put to bed all your burning questions.
I don't think any of this is contrary to what lingyi or lordsmurf has already stated (though I didn't read too closely), but was more a point of clarification, and some affirmation.

Scott

[KarMa]

Interesting read Cornucopia.

[lingyi]

Interesting read Cornucopia.

++1

Always nice to hear from someone in the field who actually worked with the equipment.

I'm curious about your statement that the signal wasn't in the VBI. This seems contrary to what I've read and seen. The pulsing white blocks (I forget what the CopyGuard signal looked like) could clearly been seen in the VBI and after being run through a TBC (I had a TBC-1000), there was no trace of the protection. If the actual signal wasn't in the VBI, where could it have been inserted?

[RennMax]

Thanks for taking the time and sharing your knowledge and yes, that does answer my question very well.

I had imagined that whatever was used to add Macrovision would have remained the property of that company so leasing makes perfect sense.

I've never suggested there was anything mysterious, super special or any type of high level control involved here. I just wanted to know, having watched and read so much how to remove the MV signal, how it was put there in the first place.

I've been a video buff since my dad bought a Sony C5 Betamax deck in the mid-eighties, which I kept until the 2000s. (I now have, the inferior but working, Sanyo VTC-5000 - as well as various VHS decks.)

I'm interested in how various signals and content, of little or no interest to the average user and would in fact never be seen, can added to analogue video format.

I'm not a member of the tinfoil hat brigade (although urban myths are always fun to hear!) I'm just interested in how a storage medium can be adapted through resourcefulness, like using the VBI for closed captions or anti-copy, to include additional material.

So of course, I'd love to hear more about the system that added the 'cursive' signature - as I'm sure others here would - but as a new member I don't be a pain and ask tooo many questions.

Much thanks to you all.

[lingyi]

This goes completely over my head. It's the spec sheet for a Macrovision encoder that goes into great detail about how, where and how different options for how the signal is embedded.

[lingyi]

This appears to be the original patent, 1987, that discusses how Macrovision works.

[Cornucopia]

To be clear: what I said of a signal that wasn't in vbi - that <edit>was</edit> referring to that 2nd, custom circuit. It was not related to Macrovision in any way. Its purpose was for authentication, watermarking & tracing, not for copy protection. It was in the "front porch" of the HBI, btw.

Macrovision DOES live in/modify the VBI.

Scott

[lordsmurf]

Thanks for the informative posts Cornucopia.

I knew folks like you at the time, but I was still in hobby mode in the 90s.

I remember hearing about watermarking tapes. I completely forget about that. Studios used to do that with VHS screeners, but it didn't disappear as quickly with dubbings. I did get review tapes in the 90s, and I know that I have several left. (You usually were required to return the tapes. Even the tapes I kept were supposed to be returned, but for whatever reason never were. Some studios tapes sucked, and had a magnetic cartridge in the clamshell, making it essentially a play-once tape. After I first saw that, I started breaking open clamshells [screw-less shells], reshelling tapes into cheap dollar tapes so I could REW/FF/re-watch for my reviews.)

[johnmeyer]

Great read, Scott!!

Somewhere in my engineering notebook I have a sketch that the lead engineer at one of the test & measurement companies I worked for sketched out for me that was supposed to defeat the "scrambling" technology used by HBO and other pay services. He explained (this was 1980) that the technology simply supressed one of the sync signals that hid in the VBI. The cable box was designed to re-insert the timing signal, using other references in the composite signal to determine how to re-insert it.

I actually breadborded the circuit, and have some of that lying around in a box of parts. I was never able to make it work.

I don't know for sure, but I think Macrovision was simply a milder version of this scrambling, where enough of the signal was left so that the TV set could sync up, but when you made a copy of the tape, the sync signal degraded just enough that your picture would lose sync.

So, if I were going to research this, I'd also search for something like "analog pay TV scrambling HBO".

[lingyi]

To be clear: what I said of a signal that wasn't in vbi - that <edit>was</edit> referring to that 2nd, custom circuit. It was not related to Macrovision in any way. Its purpose was for authentication, watermarking & tracing, not for copy protection. It was in the "front porch" of the HBI, btw.

Macrovision DOES live in/modify the VBI.

Scott

Thank you for the correction. That's what happens when I don't thoroughly read!

[RennMax]

@lordsmurf

By clamshell are you referring to the cassette casing itself. As I'm sure you know that term is usually used for the cases that commercial tapes were delivered in.

So there was effectively an erase head within the screener tape - making it a read once media?


I've come across video the term 'watermarking' but generally in contexts where it was a misunderstanding of anti-copy systems.

It sounds like the CAP branding of analogue film.

https://en.wikipedia.org/wiki/Coded_anti-piracy

[lordsmurf]

@lordsmurf
By clamshell are you referring to the cassette casing itself. As I'm sure you know that term is usually used for the cases that commercial tapes were delivered in.

Yes, case. Or shell. Not clamshell. Oops. (Doing too much today. Now tired, need sleep.)

So there was effectively an erase head within the screener tape - making it a read once media?

Not really anything fancy enough to deserve the term "erase head". Just a slim magnet tucked inside.

The first time it happened to me was with a pilot from Neilsen. Another family member wanted to see it. "Fine, go watch it, I'll view it later tonight." Nope. And I never did see that pilot. In all my years of hobby collecting, I never came across it anywhere. I no longer remember the name, but it was supposedly similar (but also very different) to Two and A Half Men -- but from the mid 90s. Maybe a cross between Two and A Half Men and My Two Dads, sort of. Remember, I never saw it, just got a butchered review from the family member, who was ironically only half-watching it (multi-tasking, aka doing two tasks miserably concurrently)

That only happened to me once, because I cracked open every tape afterwards. I may have seen 5 more ever, so it wasn't common. (Hmm. Maybe I still have at least 1 tape because it had a warning about tampering? I vaguely remember that. Better to return nothing, than return something tampered with? I do know they never inquired about non-returns, as others at work often kept tapes.)

If you're wondering why, BTW, it's because I'd aim a camera (film!) at the screen, and shoot a few shots of the actual video at 1/30s. I hated to use the promo art, because it was actually rarely in the actual finished piece. There was nothing in the specs to prevent this. But I'd know what I wanted AFTER having seen the video. REW/FF to the location. Add a TV frame to the image, and print.

It sounds like the CAP branding of analogue film.
https://en.wikipedia.org/wiki/Coded_anti-piracy

Sort of. But that's for film. This was in the non-visual data of the tape. This was probably 20 years ago now, so I really don't remember too much about it.