Greenish line at top of VHS captures?

[_Vengeance_]

:confused: Does anyone else have the problem, with capturing from VHS, of a greenish blinky line sometimes appearing at the top of the screen? :confused:

It's quite obvious at the top of this animated 512x384 screenshot:
http://www.acm.vt.edu/~clint/download/greenline0.bmp

And is still obvious even with 352x240 live-action stuff:
http://www.acm.vt.edu/~clint/download/greenline20.bmp

And, because this line is "blinky" in nature, it can get as bad as this for certain frames:
http://www.acm.vt.edu/~clint/download/greenline30.bmp
^ This one is unusual in that it is kind of purplish. Usually it is greenish.

I have 2 different VCRs that I tend to use for VHS capture. One plays dirty tapes better, and has manual tracking for those frustrating 8-year-old tapes, and one plays clean tapes better and has a digital color correction buffer ($500 vcr), but sucks at playing noisy tapes and since it is all auto-tracking there is nothing I can do to override "tapeflicker crackle audio". This is a separate issue but I thought I would mention it.

BLINKING GREEN LINE AT TOP -- I've seen this on lots of other peoples' encodes that I've sampled. Usually theres is constant. I am fortunate in that mine is not there 100% of the time or on 100% of shows.

But it irks me nonehteless! :angry:

A VirtualDub filter to look for THIS SPECIFIC ARTIFACT would be GREATLY apprecated. I do not know C++ well enough to write one myself though.
:stupid:

Any suggestions?

BTW -- I don't see this line on the TV, only on the capture card. And it tends to happen using both my Radeon's S-video input (Good VCR) and Composite/RCA input (Bad VCR). But it definitely happens more with the RCA input vcr. I don't know if that is a function of the cabling or the VCR. But it doesn't show up on the TV; only on the capture.

ARGH!

[_Vengeance_]

Sample 1. Bob & Margaret. It shows up the worst on yellow backgrounds, being green and all. Bob & Margaret, Dr. Katz...

[_Vengeance_]

Sample 2. Fawlty Towers. It can be annoying on live action because at least with animation you can temoral-smooth-the-hell-out-of-it. This really messes up live action alot worse so I can't fix it without destroying the main content more.

[_Vengeance_]

Sample 3. Eek! The Cat. This is an example of it at it's worst. Fortunately the line is only in about 25% of my captured shows. And during those shows, it only shows up about 10% of the time. And only peaks at this level 1% of the time. Still, this is UGLINESS AT ITS WORST. :devil:

[scav]

Hey Vengeance,

Did you ever find a solution to this problem? I have the the same situation, and would really like to find a filter to take care of it.

[_Vengeance_]

Nope. A Virtualdub plugin to fix this would be really nice.

I've recently learned C++ but I doubt I could do this nonetheless.

But man... it's just a matter of removing the green, when it's there. It seems like it would be relatively simple algorithm wise, it's just the implementation that would be a pain.



But .. a hardware solution would be MUCH MUCH better.

I wish it would stop.

[wiak]

i have this to
am sure Paint.NET or other photo editing software can fix it
its only some frame the problem is on not everyone
http://upload2.georgeownsme.com/files/8/1.png
http://upload2.georgeownsme.com/files/8/2.png
here is a method that might help, for filters, scan the frame before the bad frame and apply the colors in the frame before or something like that might work

[Revgen]

Try posting this in the avisynth forum. It appears to be a Luma/Chroma plane issue.

[Wilbert]

It's due to crappy ATI drivers. No fix is possible, other than cropping it away or other drivers.

[dexy]

Well, I can maybe help you to find some solution, couse I am interest in electronics too. I have probably the worst problem. In your case only color is blinking, in my case about 1/4 of the picture are curved at the top and color is blinking over the whole picture. Many people will say there is nothing I can do about that, but I supose that is not right. First advance: dont even think about some filter that can remove this, couse that is waste of time. The best solution is to fix the tape. Your tape 's track is probably sunk (uncover the tape and see it, if not, notify me about that), becouse you have probably played on different VCRs. Some of them can sunk the track, and later this tape can be played on them without this problem (like old panasonic VCRs), but when you try to play them on different VCR you will meet this problem. I will try to "press" the track so it can me played on my VCR without any problem, I suggest you to do that to if your capture is short(I can explain to you how to do that), if not that is the waste of time. Second solution for this is to capture video using VCR wich was sung track, couse it can play it without problem. In your case you have two VCRs-one old and one new($500). My suggestion is to use the old one, couse I have expirience that the old one is always better for old tapes (it has track adjustement which is much important then color adj). The recent VCRs are builded more for s-vhs tapes, and them plays much worster old tapes. Tell me what you decided and if you have some trouble with old VCR.

Sorry if my English is bad,I didnt have time to correct grammar mistakes