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  1. Member
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    Sep 2015
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    Chicago
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    Back in the mid-1980s, I participated in a school talent show. The school recorded the talent show on a VHS tape and made several VHS copies. I borrowed one of the school's VHS copies, and hired a video store to copy the talent show from the school's VHS tape to a blank VHS tape that I had purchased in a store. The video store created a perfect VHS copy on my VHS tape.

    Today, 30 years later, I attempted to copy the talent show from my VHS tape to a blank DVD-R that I had purchased in a store. I used a Sanyo DVD Recorder/VCR Combo (model # FWZV475F). Before I began the copying process, I simply played the VHS tape in one VCR and in the VCR portion of the combo. I just played the tape. No copying was going on. And the tape was played perfectly both times. The video looked very good for a 30-year-old VHS tape, with few flaws.

    However, when I began the VCR-to-DVD copying process, or the "dubbing", something weird happened. I was watching the video on the TV as the video was being copied, and there were periodic flashes of light in the video. It was as if there were 10-20 flash cameras going off at the same time. This was happening every 5-10 seconds or so.

    After the copying was finished, I played the resulting DVD in my standalone DVD player. The resulting video was the same as the video on the VHS tape, except for the periodic flashes.

    So, what's going on here? Did the video store that copied the talent show from the school's VHS tape to my blank VHS tape, add some sort of copy-protection mechanism to my VHS tape? I certainly never authorized the video store to do that.

    Please keep in mind that the DVD video of the talent show is still very watchable. The DVD video simply makes it look as if the audience is using a lot of flash photography during the show. I would, however, like to find out *why* this flashing phenomenon occurred. Any help from this forum would be appreciated. Thank you.
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  2. Member
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    Feb 2006
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    sounds like the video store might have added the dreaded macrovision copy protection.
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  3. I'm a Super Moderator johns0's Avatar
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    canada
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    Could also be that your recorder falsely detected macrovision since it's most likely the store wouldn't add protection due to the licensing cost for just a school tape.Try using another vcr to the dvd recorder if it has the inputs for video in.
    I think,therefore i am a hamster.
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  4. Member PuzZLeR's Avatar
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    Oct 2006
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    Yup. Sounds like good ol' M/V or a false positive to me too.

    You can try a different VCR, but if the problem still persists then it very likely is M/V or a false positive, and a combo VCR/DvD recorder combo will not help. You need an external solution here, as a pass-through. (And yeah, another VCR for separate playback to hook to your recorder assuming it's got A/V input since you can't "put it in between" the VCR and DvD recorder units of your combo deck.)

    -More expensive solution: TBC such as the AV-Tool AVT-8710 Time Base Corrector or DataVideo TBC-1000 (or their similar equivalent labels from other distributors).
    -More median solution: Grex.
    -Cheaper solution: A "digital video stabilizer", such as on eBay. I can't attest to the quality of these units, but the price is usually agreeable if you want to take a chance.

    Wondering if that video store owner that made those copies is still around/alive...
    I hate VHS. I always did.
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  5. I think I know the actual problem here, but since the OP's last activity on the forum was 8 minutes after starting this thread and this reply is 2 months late it's not likely to help them.

    Funai makes the DVD recorder mentioned, sold under the Sanyo, Magnavox, and Toshiba names. They also made (make?) machines branded as Philips.

    The problem lies with the AGC used by Funai's TBC. Evidently, it horrendously overreacts when an overly-bright signal is input. The user Mini-Me described this.

    Originally Posted by Mini-Me View Post
    I'm now using a Philips DVDR3475 as a passthrough TBC ... It works excellently as a line TBC, and it cleans up squiggly lines and geometric distortions perfectly (just as well as my AG1980's field TBC, but without the drawbacks of DNR and field tearing).

    ...

    Actually, it's flickering FAR too much, and it's very annoying in motion. The flicker is triggered by high or out of range white values in the signal, so the workaround is to reduce the contrast with a proc amp before the signal gets to the DVDR3475...but that's yet another piece of equipment.)

    ...

    It significantly increases the contrast of the image in my signal chain though, so I need to correct for that. In and of itself, that's not too bad...but it digitally clips the input signal in the process, and it has a completely insane AGC that that likes to increase (yes, increase) the contrast when input levels clip too much. This causes crazy flickering in bright scenes and blows out some whites. The worst blowouts are equivalent to my AVT-8710's output all the time, but the flickering can be extremely distracting, and I've since learned just how much both better things can get: You can fix the AGC issues by putting a proc amp in front of the DVDR3475 and reducing the contrast. This eliminates the flickering and generally gives very graceful levels without any blown out whites...but you do need to be careful about garbage material or unrecorded sections between scenes, because they can still clip and screw up the AGC for the next scene (resulting in sub-optimal levels and a lack of predictability/consistency between captures).
    The reason the Funai combo is able to play the tape without flashing when not in "dubbing" mode is that the TBC is bypassed. It outputs dirty horizontal line sync straight to the output. When "dubbing" mode is engaged, the passthrough output and the DVD recording both go through the TBC step first, wiggling lines are straightened, and the AGC is encountered.

    The two samples attached are each the same video that both demonstrate the flashing. One is just recorded from the passthrough and the other ripped from the recording that the machine made. It really goes nuts at the end when the "fade to black" setting of the camera is engaged.
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