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.

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....

Your guess is as good as mine, Tom. I can't find a manual for it online, so I can neither confirm nor deny. It's a piece of pro equipment, so I can't think of a reason for it not to completely strip and reinsert sync. Here's an Ebay link to one just like it:

http://www.ebay.com/itm/For-a-FA-310...item4184a68490


I'm at a loss, I just wanna watch a damn movie! :sigh:

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

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.

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.

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.

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

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

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.

I remember when Macrovision encoding was first used on movie tapes, and it turned out that the system had been only designed and tested on VHS VCRs. So, anyone with a Beta VCR could copy rented tapes just fine! :) (Except for the fact that home-format tape-to-tape copies were rather lousy quality in any case.)

Most machines had a Macrovision detector that would block the record button signal from activating the record circuit, VCRs without that circuit (such as pre-lawsuit ruling Beta decks which were built that way on purpose) would record a macrovision laced signal Macrovision and all to tape without a care....In fact if one can identify the macrovision detector stage in any VCR or video recording device and disable it then it should be possible to copy a macrovision protected signal (albeit perhaps with AGC confusion effects) without stripping the mac...

Finding and defeating AGC would do it. In fact, on the wiki, there was mention of a US law barring import of any VCR without AGC, simply because the macrovision process relies on it.

Chip

Yah if you can defeat the AGC that would do it. And there were very inexpensive
boxes that use to be for sale that would do it.... In the days of Wometco Home Theater
over broadcast tv in NJ it was a home brew activity to build yer own little box for that.
It involved restoring the sync pulse to its proper amplitude. I imagine its just about
the same for macrovision.

This is the way the box use to be advertised, just like this one on ebay today....

-------------- This is from the ebay ad link above ----------
Digital Video Stabilizer w/ Copyguard


*
o Brand new! in the box!
o Eliminates video related symptoms: brightening, darkening, color shifting, jitter, shake, & more...
o Stops rental movie picture problems.
o Removes all picture distortion caused by copy protection. Enables copying of videotapes
to DVD by removing copy protection. Back up your videotape collection to DVD.
o S-Video or Analog input
o Analog cable included
o AC Adapter included
o Works for first and second generation Macrovision.
o Model: SD6038


----------------------

It's the brightening and darkening of the pic, it makes a copy loose sync.
I think it would be cool to get one and reverse engineer it....


.

Only machines I ever saw when I repaired them for a living that would block or shut down the Rec mode were the later model Go-Video units after they (Sensory Science Corp) lost the lawsuit against them. Put in a tape, hit "copy" it would run for maybe 5 seconds until it detected macro-crap, and shut off with a blue screen message. Other VCRs would simply record garbage for an hour or two.

I would not consider using a time base corrector specifically to remove macrovision. A timebase corrector is designed to address the variable write and read head to tape velocity variations which leads to playback time base error on video tape. It may as an option, include means to blank lines in the Vertical Blanking Interval but there is no guarantee as this is not the device's primary purpose.

In the old days of analog television broadcast, a video processing amp was inserted at the output of a studio production video switcher or the output of TV station feeding the transmitter. The processing amp would re-insert horizontal and vertical sync pulses and color burst and would generally include the ability to blank unwanted lines. Whether the Time Base corrector or Processing Amp devices can blank the macrovision lines immediately after the vertical sync is another question. The manufacturer may have obliged us by including this extra feature.

I personally would tend to avoid a timebase corrector as they often degrade composite video quality. The time base corrector would unnecessarily decode the NTSC chroma, the luma and chroma would be digitized, then re-clocked and then go through digital to analog conversion and then the NTSC chroma would be re-modulated. The quality of the resultant video depends upon the cost of the Time Base Corrector. The Processing Amp is perhaps a better choice as it would only replace the video sync and the color burst: the active video will be untouched.

The simplest solution may be simply to build a device with monostables to blank specifically the macrovision lines.

Thanks Greg, just got it in the mail and it works! No more macro crap, and cheap too! Only question now is, what to do with this apparently useless TBC? It does have neat features like freeze frame and picture and chroma adjustments in it, but in truth I can't see retaining it. Anyone want it for what I paid? I think it was $100 shipped.

It would be interesting to see the internals of one of those - to see how close it is to the old Macrovision Scrubber circuits we used to build. Radio Electronics had a first-generation one in the Dec 87 issue - it works, but the second generation Macrovision (non-tape media) made it almost obsolete.

Probably uses logic gates to strip the original pulses and replace them, there's not much inside it I can tell you that much. A power supply, and a few IC's is about it.

I wanna watch them also AND THAT MACROVISION CRAP MAKES THEM LOOK BAD!!!!

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)

Can't do it without the box!

:(

Honestly it's $50 well spent, I just hope it lasts a while because it's certainly made in China...

The video is not processed digitally in this box, as far as I know. There certainly are pulse/timing circuits to fix the blanking interval.

It looks like the one in Radio Electronics counts lines, and switches a newly-generated vertical interval in place of the macrovisioned-one. So, the actual program material you see is unaltered, not digitized and processed. All the information needed to build your own seems to be in the article, probably including the artwork for the circuitboard. You can mail-order boards made on a one-off basis, and populate it yourself if the parts are still available.

It's quite likely that the $50 version does things the same way...

Chip

Score one of the "stereo" RF modulators sold by Radioshack between 2000 and 2003. Somehow they more or less blatantly ignore macrovision.

does anyone know the model number of that Radio Shack modulator, I see a lot on ebay, but hard to tell which is which.

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.

No, this was the regular $29.99 modulator box at the time. It has composite and L/R RCA jacks and an S-Video jack (Screen-door on a submarine!) on it, and the only thing up front was a red LED. I'm gonna go dig through some things and see if I can't scare up the part number for us. (I worked at the shack from 2002-2005.)

Actually it is called a "Theater 2001" stereo modulator. I had to go look to refresh my memory. Cost was way more than $29.95 for a true MTS stereo modulator back then, more like $200-300. I don't know if it removes the copyguard junk.

Hmmmm I wonder if I have that one??

I found 2 RF modulators @ salvation army and 1 of them has what you describe!

Cat # PH61159 (PH - Philips??)

On the back its got

RF in/out Audio L/R VIDEO IN and an S-video jack.....

On the front

A RED light (MOD. ON) and a channel 3 or 4 switch......

Could be the same beast in disguise...

15-1214 (Read the date code label on the actual unit, this was changed to "15-1214A" sometime in 2004 but the part number and UPC are the same, so one that says 8A02 or 04A03 is just fine, but 02A05 is a no go. (last two digita are year of manufacture.)
15-1215 (Same as above, but this one has 4 sets of inputs.)

15-1244 might also work, it was the "not-stereo" version (no S-video, and the L and R channels are just summed internally.) again though look for production runs after 1999 but before 2004.

There is no date code on it..........

I looked @ the back and nothing..........

Here is what it looks like

http://images.philips.com/is/image/P...S2_PH61159-IMS

Sometimes comparing the FCC ID numbers will help clarify things.

Chip

Catalog number on the stereo one is 15-2525. It has "stereo" written on the case.

https://www.youtube.com/watch?v=jk0wDG_bZwc

Interesting. This modulator I have that I bought over at the Radio Shack Clearance Center (...in FW off of Northside Drive and I-35W, used to go there every 2nd or 3rd Saturday don't remember exactly at 7 AM lined up and waiting...) back in 2000-2001 is an early possibility they probably cleared out, too expensive. I bought 3 of these discontinued items for $30 ea. No single chip wonder here like in their later model in Chris Cuff's video. Notice the separate DBX encoder chip to make it exactly right. VR2 I marked on the board back then, that's the video level. Was low out of the box.

http://i125.photobucket.com/albums/p...ps98866940.jpg

Too bad that was not there when I was a kid ... that is walking distance of
my home! And my mother was, for a time, Mr. Tandy's receptionist.

It was a near ritual to go over there every month to see what they would have. Ham radio guys and others would set up to sell stuff in in the parking lot an hour or so before 7 then the big rush to get to the goodies first.

Anyway I guess I should hook up this modulator someday, run a macro'd tape through it and see if it gets striped out. Never checked for that. I used it with my old big dish C-Ku band satellite receiver to send Ch 3 in stereo to a couple of TVs in other rooms.

Hey, I have one of those. I got it years ago. I thought the (then) company had gone out of business, because the link I posted in a website article stopped working long ago. Maybe they changed distributors or something. No idea what's inside, but it gets the job done.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html