Help me to solve this Dot Crawling artifacts

[Kaiousama]

I'm trying to fix the dot crawling problem present in the US dvd release of Argento Soma (Bandai), the master is generally quite good but this artifact affects almost every episode.

You can find a sample clip exposing the problem uploaded here (http://www.freewebs.com/kaiousama/test/dotcrawl.vob). (original vob cutted)
Dot Crawling artifacts are wuite evident around the red lines drawed into the two elevator's monitors behind the researcher.


I've looked for a dot-crawling dedicated avisynth filter and i've founded only Linsley Dubb's GuavaComb.
Unfortunately i wasn't able to solve the dot crawling atrifact even with very aggressive settings for the filter like those reported in this example script:


# --> Video Opening <--
mpeg2source(".\DotCrawl.d2v")

# --> Crop / Artifact Removing <--
ConvertToYUY2()
SeparateFields()
GuavaComb(Mode = "NTSC", Recall = 0, MaxVariation = 80, Activation = 0)
Weave()
ConvertToYV12()
Crop (4,0,-4,-0)

# --> IVTC <--
Telecide(order=1, guide=1, post=2).Decimate()


Maybe there are better settings, maybe i've chosen the wrong filter for this case.
Maybe Linsley Dubb can enable his filter handling Dot Crawling scenarios like the one present in my clip.

Best Regards.

[edit]: even with other filters suggested on the forum like DeDot or
DeGrainMedian(limitY=5,limitUV=10,mode=0) i wasn't been able to remove the dot crawling, i'm a bit discouraged :...(

[Dreassica]

U might wanna give dedot a try. It's in my opinion superior to guavacomb when it comes to dotcrawl.

[Kaiousama]

Unfortunately DeDot cannot remove the dot crawling effect in this particular case, i've tried it in these two configurations (suggested in the forum):
DeDot()
DeDot(20,20,15,5)

and even combined with DeGrainMedian didn't worked:
DeDot()
DeGrainMedian(limitY=5,limitUV=10,mode=0)

I cannot tweak DeDot parameter because the help file is not in english (maybe japanese?).

Thanks for your reply.

[Tri]

You could try the DotCrawl Filter (http://home.earthlink.net/~tacosalad/video/dotcrawl.html) for VirtualDub. To add it into an Avisynth Script, use this after you load your plugins:
function VD_DotCrawl(clip "clip", int "temporal", int "spatial"){
LoadVirtualdubPlugin("I:\Eigene Dateien\Programme\Mutlimedia\DVD\VirtualDub Mod\VirtualDubMod\plugins\dotcrawl.vdf", "DotCrawl_Comb_Filter", 1)
return clip.DotCrawl_Comb_Filter(default(temporal,1), default(spatial,1))
}
To use this function at a specific place, type
ConverttoRGB32(interlaced=false/true)
VD_DotCrawl(4,3)

The params 4 and 3 are only what I used for the Kenshin OVA...
The drawback is that you have to convert to RGB before using it. While I was not able to completely remove all horizontal crawling, most of it was gone after I had used DotCrawl three times in a row :rolleyes:. The video became a bit blurry, though.
Also, if the video contains flashing light effects (like the Kenshin OVA does), you have to exclude these scenes from decrawling with DotCrawl, otherwise you would get really nasty artifacts.

[madness]

the down side of that vdub filter if you set the temporal too strong I think, you get ghosting when the video pans and its rather annoying.

[Kaiousama]

@Tri:

This DotCrawl filter worked well in this case (80% of the perfect result is achieved), i've used this script:


#---------[ DOT CRAWLING ]--------------

# --> Video Opening <--
mpeg2source(".\DotCrawl.d2v")

# --> Crop / Artifact Removing <--
ConverttoRGB32(interlaced=true)
VD_DotCrawl(4,3)

ConvertToYV12()
Crop (4,0,-4,-0)

# --> IVTC <--
Telecide(order=1, guide=1, post=2).Decimate


and here are the results (first original picture, then filtered picture):

http://www.freewebs.com/kaiousama/test/dotcrawl1.png
http://www.freewebs.com/kaiousama/test/Filter1.png
http://www.freewebs.com/kaiousama/test/dotcrawl2.png
http://www.freewebs.com/kaiousama/test/Filter2.png


The filter was able to completely remove the crawling in the first image samples.
In the second image samples it removed a big amount of crawling but not completely, especially over the small orizonal red lines.

In the resulting video there are annoying luma oscillations (flickering) around the zones that were affected by Dot Crawling.
The flickering effect was already present along with DotCrawling in the original clip but masked by its evidence, now that DotCrawling is removed the flickering is more noticeable.

Did you experienced a similar side-effect when filtering kenshin OVAs ? any idea of how to minimize it?

(btw Kenshin OVAs are one of my favourite anime, unfortunately ADV made such an horrible english authoring/translation)

Thank you very much for your help ;)

@madness: how strong did you set the filter when you experienced ghosting artifacts?

[madness]

@Kaiousama
I'm not quite sure but I tried that filter like a few months ago and I couldn't remember what setting was it gave me ghosting. If I got time tonight I'll have a look at it again see if I can reproduce it.

[Edit]
Also I just got a DVD rip of an anime which has dot crawl on it and it's visible everywhere. So probably I got some experiments to do tonight.

[Tri]

Originally posted by Kaiousama
Did you experienced a similar side-effect when filtering kenshin OVAs ? any idea of how to minimize it?
I remember there was some flickering left, especially at 00:01:44 (Kenshon OVA Ep 3) around the colored trees in the background. I used Golddust(limit=7) followed by xsharpen(35,35), which took a little care of it (but some flickering is still noticable which I didn't bother to filter out any more :/ ).

Regarding your clip, I could reduce the horizontal flimmering (with the exception to that in the square) by using two additional instances of VD_DotCrawl(4,3), however, it would create fuzzy lines and a blurry image.