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  1. Member
    Join Date: Apr 2009
    Location: United Kingdom
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    Is there a name for this particular type of noise?



    Does anyone know if there is a specific cause?
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  2. Are you talking about the diamond shaped pattern or the vignetting? You should post the full frame with no resizing.
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  3. Member PuzZLeR's Avatar
    Join Date: Oct 2006
    Location: Toronto Canada
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    It's hard to tell with that small pic - as Jagabo says, a full frame would help. A small clip would be even better.

    It looks like a form of herringbone, but it's way too blurry to tell what caused it for sure whether it's composite crosstalk, tbc's signal thrown off, cable/electrical interference, or any number of other things.
    I hate VHS. I always did.
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  4. Member Noahtuck's Avatar
    Join Date: Jun 2004
    Location: ®Inside My Avatar™© U.S.
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    Cause of Noise
    Too many beans & beers ?
    Originally a member since 2001, LONG LIVE TARAN's!!!
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  5. Originally Posted by magikarp99 View Post
    Is there a name for this particular type of noise?
    Pattern?
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  6. Member
    Join Date: Apr 2009
    Location: United Kingdom
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    Originally Posted by jagabo View Post
    Are you talking about the diamond shaped pattern or the vignetting? You should post the full frame with no resizing.
    The diamond pattern. The frame has been cropped, not resized. I will try and find a larger frame to demonstrate the noise.
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  7. You need to provide some background information too. What is the source? Did you capture this from a VHS tape? Is it an off-the-air recording? Cable broadcast? DVD? Since you're in the UK it must be PAL. If this is your own video capture -- what type of cable did you use? Composite? S-video? SCART? Was that part of the picture moving or standing still? Does the pattern change from frame to frame? Does the pattern repeat every 4 frames?
    Last edited by jagabo; 12th Apr 2014 at 08:31.
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  8. Member themaster1's Avatar
    Join Date: Nov 2006
    Location: France
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    read here:
    https://en.wikipedia.org/wiki/Dot_crawl

    edit:
    Actually it looks more like herringbones (thanks PuzZLeR)

    to get rid of it use f1quiver (you'd have to tweak it a bit):
    F1Quiver(last, "gn", 336, 10, test=false)

    http://www.avisynth.nl/users/vcmohan/FFTQuiver/F1Quiver.htm
    Last edited by themaster1; 12th Apr 2014 at 12:44.
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  9. Member
    Join Date: Apr 2009
    Location: United Kingdom
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    The tapes I am looking at are PAL. They are not recorded by me. One is a mass-produced tape, and others from from post-production studios.

    The deck I am using is a JVC BR-S525E with TBC cards installed. I am using Y/C video output, but the noise is also present on the component output.

    I think that the noise may be recorded onto the tapes themselves as I don't think that all my tapes are affected. At the very least, some tapes are affected much worse than others.

    The pattern moves from frame to frame.

    It does look like it might be the herringbone noise that was mentioned.
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  10. Does it show up on grey parts of the picture? If not it's probably dot crawl artifacts -- the result of incomplete removal of the chroma from the luma signal when separating composite video. It's much blurrier than the usual PAL dot crawl pattern so it must be on the tape. Ie, a composite signal was recorded onto the tape (where it is separated into separate chroma and luma signals) then played back as s-video. PAL dot crawl has a pattern that repeats every 4 frames. So if you use SelectEvery(4) in AviSynth you should see a pattern that doesn't change in otherwise static parts of the picture. Though with VHS there's always some time base jitter so it won't be perfectly still.
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  11. Member
    Join Date: Apr 2009
    Location: United Kingdom
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    So here are two video clips that demonstrates the noise well. I've cropped one of them down to reduce file size.

    Using SelectEvery(4) does not freeze the pattern.

    Greyscale clips within the tapes do not exhibit this noise.

    noise.avi
    noise2.avi
    Last edited by magikarp99; 13th Apr 2014 at 07:09.
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