mosquito swatting

[FredThompson]

I'm looking for suggestions on how to remove mosquito noise from animation and B&W (In Harms Way R1). Normal grain/noise removal works quite well but on source with pronounced compression mosquito on edges, the mosquitos seem to become more prominent. They're really not, it's just the contrast between them and the cleaner areas is more evident. Donald Graft's MSmooth was wiping out too much detail in the animation I had (Heavy Metal anniversary DVD R1) so I'm hunting for other options. Searching on "mpeg artifact" and "mosquito" don't turn up any recent developments. Weren't there some fairly new filters which are aimed at this stuff?

[Didée]

BlindDeHalo3( PPmode = -1 ) # or -2
Can't guarantee that the internal masking is fitting tight enough to the affected areas, though ... but basically this should do it.
Out of the existing pre-made functions, good old HQDering is another possible option.
Oh, and there's TBilateral, too ...

[FredThompson]

Dehaloing will remove mosquito noise?

[Mug Funky]

halo = gibb's phenomenon

mosquito noise = gibb's phenomenon manifested in a different way.

whenever you run a filter that affects frequency, you get ringing. dehalo'ing will attempt to remove this (at the expense of some distortion, but hell, we're not listening to audio here, and it's amazing just how much you can distort a video signal and get away with it).

[FredThompson]

Who is this Gibb person? I'd like to smack him!

[Revgen]

Well, I don't have the script on hand, but I had a whole bunch of mosquito noise and blocks in my Garfield TV season one DVD.

So, I had to use a combination of FFT3DFilter and MSmooth along with Stickboy's JDL_ApplyRange function to adjust FFT3DFilter and MSmooth's strength in certain areas of my movie so it would work in dirty areas and not smear details in clean areas.



Okay, lets say frames 0-1000 are dirty, frames 1001-2000 are clean and frames 2001-3000 have strong noise again. Here is a rough example of what script I used.

LoadPlugin("mydrive:\msmooth.dll")
LoadPlugin("mydrive:\FFT3DFilter.dll")
Import("mydrive:\JDLutil.avs")
Import("mydrive:\JDL.avs")

whateversource("myvideo.myvideoextension")

JDL_ApplyRange(0,1000, "Msmooth("my strong settings")")
JDL_ApplyRange(0,1000, "FFT3DFilter("my strong settings")")

JDL_ApplyRange(1001,2000, "Msmooth("my weak settings")")
JDL_ApplyRange(1001,2000, "FFT3DFilter("my weak settings")")

JDL_ApplyRange(2001,3000, "Msmooth("my strong settings")")
JDL_ApplyRange(2001,3000, "FFT3DFilter("my strong settings")")

[*.mp4 guy]

You could also use 708145's smoothd filter. It uses multiple overlapped quantisized (is that how thats spelled?) blocks to remove most types of dct noise.

[Chainmax]

Well, UnDot is supposed to clean up mosquito noise. In that line, you could use RemoveGrain(mode=1) or (mode=5). You could also use DeGrainMedian().

[FredThompson]

UnDot is more of an area-based change clamp. Turns out I'm getting incredible results with DeHalo_alpha (ever heard of it? :P) and either LRemoveDust or DeGrainMedian.
Screenshots are on my webpage.

[unskinnyboy]

Who is this Gibb person? I'd like to smack him!
Josiah Willard Gibbs (http://en.wikipedia.org/wiki/Willard_Gibbs). No use smacking him, he just discovered the phenomena. He didn't create it. :D He is dead anyway.

[Didée]

Hmh, those screenshots show aliasing and median-cut effect on weaker lines and in areas of fine shadings. Using LimitedSharpen without any supersampling is always prone to give aliasing... Did you try "soft=~24" in LS ?

BTW, seems I somehow lost the links to the samples for toying around ... could you perhaps post them again? :p

[2Bdecided]

To bring this thread back from the dead, are there now better (i.e. less destructive) solutions for subtle mosquito noise? I'm working with animation. It's almost invisible on the original, but upsizing + sharpening makes a slight grainy pattern around edges visible - I'd like to avoid it or get rid of it.

Cheers,
David.

[DarkT]

might be completly off, but I think I remember dfttest being good with mosquito noise...

[*.mp4 guy]

Post a sample of the source.

[McCauley]

Hi,
I'm working with animation. It's almost invisible on the original, but upsizing + sharpening makes a slight grainy pattern around edges visible - I'd like to avoid it or get rid of it.you could try
MCTemporalDenoisePP(edgeclean=true,ECmode="dfttest().dehalo_alpha()")
Regards
McCauley