Is there a name for this particular type of noise?
Does anyone know if there is a specific cause?
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Are you talking about the diamond shaped pattern or the vignetting? You should post the full frame with no resizing.
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.
Cause of Noise
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 07:31.
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)
Last edited by themaster1; 12th Apr 2014 at 11:44.
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.
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.
Last edited by magikarp99; 13th Apr 2014 at 06:09.