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-   -   TBC question: macrovision removal? (http://www.videokarma.org/showthread.php?t=263186)

Penthode 12-18-2014 06:14 PM

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.

miniman82 12-23-2014 11:50 AM

Quote:

Originally Posted by Gregb (Post 3121394)
I bought one of these and it works awesome!! The picture is free of that macro nonsense and crystal clear.

http://www.ebay.com/itm/Digital-Vide...item2a479e1918

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.

Findm-Keepm 12-23-2014 12:23 PM

Quote:

Originally Posted by miniman82 (Post 3121831)
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.

miniman82 12-23-2014 09:05 PM

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.

Dude111 12-26-2014 12:40 AM

Quote:

Originally Posted by miniman82
I'm at a loss, I just wanna watch a damn movie! :sigh:

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)

miniman82 12-26-2014 08:55 AM

Can't do it without the box!

Dude111 12-26-2014 03:17 PM

:(

miniman82 12-26-2014 05:32 PM

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

old_tv_nut 12-27-2014 10:30 AM

Quote:

Originally Posted by Dude111 (Post 3122037)
:(

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.

Chip Chester 12-27-2014 04:33 PM

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

NoPegs 12-28-2014 02:19 AM

Quote:

Originally Posted by Dude111 (Post 3122007)
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)


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

Olorin67 12-28-2014 09:42 AM

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

Ed in Tx 12-28-2014 09:48 AM

Quote:

Originally Posted by NoPegs (Post 3122132)
Score one of the "stereo" RF modulators sold by Radioshack between 2000 and 2003. Somehow they more or less blatantly ignore macrovision.

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.

NoPegs 12-28-2014 09:51 AM

Quote:

Originally Posted by Ed in Tx (Post 3122144)
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.)

Ed in Tx 12-28-2014 10:01 AM

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.


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