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#1
06-14-2019, 10:23 AM
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Eliminating copy protection retrace lines
Hi All,
Some DVD's that I have give my Predicta the dreaded re-trace lines from copy protection or whatever. I see a couple of home-brew projects out there but time is at a premium for the next few months and I would rather find an off-the-shelf solution. Would this work? https://www.amazon.com/XDIMAX-GREX-7.../dp/B0096I2DNE A bit pricey but if it works I'd be happy. Any other available options welcome, including buying one used from one of y'all. Thanks! 
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#2
06-14-2019, 12:06 PM
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From the description, it does what you want.
Definitely buy through Amazon so you can return it if it doesn't work. Have not seen this particular unit before. Some other ones I have seen in the past (and have had) had a tendency to degrade the color burst a bit, and older sets might not like that.
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#3
06-15-2019, 08:04 AM
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Well, I went ahead and ordered it. I'll let you all know if it works. Is this type of retrace line uncommon? I would have thought this crowd would have a "go to" solution like the BT modulators for RF signal generation.
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#4
06-18-2019, 05:01 PM
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Macrovision is hidden in the vertical sync bar on a few lines as a white line signal of varying intensity. It dips below 100 units IRE and the recording unit's sync passes some video for a bit until the line floats up to around 140 units of video. Above 100, the recording unit's automatic video level kicks in and tries to crush the video back to 100 which also crushes the recording sync level down below usable and the picture falls apart. Some recorders have Macrovision sensing inside and give you the "cannot record" warning. These adapters usually just reinsert new sync on the transmitted signal. RF is not the problem, it is doing its fine job getting the signal there.
__________________
“Once you eliminate the impossible...whatever remains, no matter how improbable, must be the truth." Sherlock Holmes.
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#5
06-20-2019, 08:46 PM
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Well, it works great! I'm sitting here watching The Streets of San Francisco which formerly had the dreaded retrace lines and it looks great.
 No picture degradation that I can see. Totally eliminates those annoying retrace lines. No we'll see if it holds up over time. But so far so good!
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#6
06-20-2019, 08:53 PM
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 Thanks for the report!
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#8
07-10-2019, 07:15 AM
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Better get one quick before the gov't makes them illegal.
I tried using a broadcast type proc amp to clean up the vertical interval and it didn't work. Its says it works for DVDs also. As I understand it, there are several styles of copy protection used over the years. So, I suppose it works on all of them???
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#9
07-10-2019, 08:29 AM
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I have no idea what copy protection schemes it works on. All I know is that some of my DVD's used to have the issue and the ones I have tried since I got the device work fine. But I have no idea what protection the DVDs I have use or if they are all the same or what. This week I'll try all the DVDs I have that had the issue.
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#10
07-10-2019, 03:55 PM
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Many video production switchers of the day would either discard and rebuild the vertical interval, or allow you to do a 'wipe' that excluded the source's vertical interval from the switcher's output.
Some full-frame timebase correctors, freeze-frame units, or frame synchs did too. All of the above are pretty cheap nowadays, though they do chew up some real estate and electricity.
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#11
07-10-2019, 08:31 PM
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Not sure what the scheme of these newer devices is but Macrovision in the day sued bunches of mfrs to get them off the market. Some settled and some sold out to Macrovision. Macrovision morphed in to Rovi in 2009 and became a software and analytics company and in 2016 bought TiVo as they exist today. Part of the Digital Millennium Copyright Act (2008) contains language banning devices made specifically to thwart Macrovision type devices.
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“Once you eliminate the impossible...whatever remains, no matter how improbable, must be the truth." Sherlock Holmes. Last edited by Dave A; 07-10-2019 at 08:39 PM.
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#12
07-11-2019, 02:03 PM
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Having analog-video-specific language in the DMCA seems somewhat comical. Almost as much as having the corporate remnants of Macrovision now owning TiVo, the groundbreaking DVR device.
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#13
07-11-2019, 08:14 PM
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Chip, it is comical now but was strangulation in the day and a world-wide agreement. The TiVo remnants today are a genius reinvention of a name. If you use Facebook you are using some of their analytics. But your new TiVo is a third-party hardware now.
And another analog copy workaround is a vintage Betamax. They re-inserted sync just fine. Use one as a pass-through even if it does not play.
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“Once you eliminate the impossible...whatever remains, no matter how improbable, must be the truth." Sherlock Holmes. Last edited by Dave A; 07-11-2019 at 08:18 PM.
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#14
07-11-2019, 09:15 PM
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During the days of Macrovision I worked in a large video production/post facility. Spent as much time making sure it worked for our customers as I did 'managing' it on customer playback equipment... the same ones who insisted we have it run thru Macrovision. Also making sure that it didn't kill closed captioning signals, which are on line 21/field 1 (mostly). A somewhat level-sensitive data signal nestled one line away from a deliberately wacky video signal.
Good tip on Betamax for those in need. Have a couple no-longer-used satellite/SD TiVos, plus the ever-popular Replay TV just for good measure.
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#15
07-11-2019, 11:34 PM
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Quote:
How did they ever figure that out???
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