Jittery horizontal line in middle of screen

[Kereellis]

Hello again. I don't expect there to be a pretty solution to this, but I'm facing an issue with a tape that for at least the first 1 hour (and probably the remaining 3 too) suffers from a horizontal jitter in the middle of the screen as it should be visible in the attached screen capture. My guess would be that it is some sort of a timing error, but oddly enough both the inline tbc of the jvc and 1t-tbc are in use. I also tried the stabilizer option of the jvc, and playing back the tape on another vcr directly connected to the tv-set, where the problem would still occur.

Any suggestions on what's causing this? Could a tape repair service perhaps help me to remove this mid-screen division line or is it easy to fix somehow?

EDIT: I forgot to mention that the effect does lessen after a while, i.e. the jitter in the middle becomes bit smaller, but even after over an hour of replay it hasn't disappeared yet.

[Kereellis]

Excuse me, I included the wrong attachment and had to remove it quickly to prevent being unable to edit the post. Here is the screenshot I referred too.

nmooilijn.jpg

[admin]

There's really no way to remove those mid-picture errors.

It's one of the few errors I can't explain just yet, although I'm looking for answers why this happens. From an educated guess, it's a mix of timing error, combined with either tape and/or head damage when the signal was recorded.

Sometimes the frame sync inside of a Panasonic ES10 helps -- or similar devices or functions within other DVD recorders and high-end VCRs. The TBC inside of the AG-1980P or JVC SR/HR series S-VHS machines have little to no effect. In fact, sometimes the TBCs can just make the error more pronounced on screen.

[Kereellis]

Quote:

From an educated guess, it's a mix of timing error, combined with either tape and/or head damage when the signal was recorded.

Strangely this tape never had any problems before. I had last seen it in november 2008, and I'm certain it was fine then (and before that). Just saying that that may rule out the recording as a cause.

[admin]

If that's the case, then it may have been damaged in the last ~2 years. One of the VCRs or cameras it's gone through may be scratching or warping the plastic/poly tape materials.

Of course, people's memory's aren't even remotely close to as good as they think they are. It's one reason I write everything down. Bad memory is why there's so many myths on the Internet; for example, "my data disappeared from my DVD" -- usually just somebody remembering wrong (or having never tested it, therefore no basis on which to make the current claim.)

So if the memory is accurate, damage. (It may not be the tape, maybe just the VCR?)

If memory is bad, then it could be signal issue as easily as tape/mechanics issue.

I know how aggravating this is. I feel for you.

[robjv1]

Quote:

Originally Posted by admin

Of course, people's memory's aren't even remotely close to as good as they think they are. It's one reason I write everything down. Bad memory is why there's so many myths on the Internet; for example, "my data disappeared from my DVD" -- usually just somebody remembering wrong (or having never tested it, therefore no basis on which to make the current claim.)

I agree with this as well. I've made many assertions ("this tape was NEVER in this bad of shape before", "This video used to be so much more colorful and sharp") only to stumble across untouched backup copies of the original tapes that display the exact same problems.

One question I want to ask -- is this tape a first generation tape or is it a copy? I have seen two tapes in my collection with this exact problem -- one was a first generation tape and the Panasonic ES-10 cleared it right up. The other was a dubbed copy of another tape (SP mode) and I can only presume the reason I could not fix it was because it was a dubbed copy and it was already "baked in" to the image.

[admin]

Quote:

Originally Posted by robjv1

One question I want to ask -- is this tape a first generation tape or is it a copy?
a dubbed copy of another tape (SP mode) and I can only presume the reason I could not fix it was because it was a dubbed copy and it was already "baked in" to the image.

Good catch!

That may be the issue, too!

While there is still limited filtering options from latter-generation copies, it does become harder at each generation. It mostly depends on the quality of the signal being passed by each successive VCR.

Judging from the what I see in lower and left/right overscan noise, I'd bet this is a first-generation recording. Then again, that chroma noise at the top overscan is often a tell-tale sign of generational copying. But only Kereellis could confirm or deny that.