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  1. I don't know how it's called, it doesn't look like grain, and I already applied SMDegrain():



    Also offtopic, but what to use to give it also some sharpness? For example the face in the right is really blurry. This image is after applied smdegrain, avs levels, and MSharpen(threshold=1,strength=100), but it doesn't really add any much of sharpness.

    I found out it might be called dotcrawl.
    Last edited by rhaz; 4th Feb 2014 at 06:43.
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  2. May I ask you what is your source?
    Did you compare same frame with your source?
    1) Try to apply one filter at a time and compare with source.
    2) Try to change encoder, apply same filters and compare same frame with source.
    3) Try to change encoder, apply one filter at a time filters and compare same frame with source.

    As I am not an expert, may be some avisynth expert will assist/help you further.
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  3. Well, source is some poor PAL 25FPS. It's of course interlaced too. And I don't see any reason changing encoder? I use the one that comes with MeGUI. I was just expecting someone could list filter names to be best to use.
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  4. Member
    Join Date: Jun 2012
    Location: USA
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    Your issue isn't dot crawl. Your issue is that the chroma (color) signal is delayed (shifted to the right) of the luminance signal. Notice how the color on her arm doesn't go as far as her shirt on the left?

    And degrain filters work by softening (blurring) the image. Of course it looks less sharp.

    Start here:

    http://www.doom9.org/index.html?/capture/chroma_artefacts.html
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    Join Date: Oct 2004
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    -30-
    Last edited by sanlyn; 19th Mar 2014 at 07:26.
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  6. It's both dot craw and chroma shift. A 3d comb filter should help with the dot crawl artifacts (the checkerboard pattern at colored edges). A chroma shift filter can realign the colors with the greyscale image.

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    A 3d comb filter requires multiple frames of video. Since I only had one frame to work with I used a blur/sharpen to eliminate the dot craw. That caused blurring of the rest of the picture of course. A proper 3D comb filter wouldn't do that.

    I think I went a little too far with the chroma shift. I shifted chroma left by 6 pixels. 4 or 5 might have been better.
    Last edited by jagabo; 4th Feb 2014 at 09:29.
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  7. My sources are retail DVDs. And I can't find anything about '3d comb filter'. However I tried using DeDot and you can see in this example at doom9 it works fine, but when I apply it to my source - nothing happens, doesn't reduce any crawling. Maybe I use wrong order in my scripts? When do I apply DeDot? After interlacing, degraining, sharpening, leveling or before?

    Also that pic ^ looks a bit too blurry.
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  8. Member
    Join Date: Sep 2007
    Location: Canada
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    Most dotcrawl filters work best when applied before all other filters . Other commonly used filters for dotcrawl include tcomb, checkmate

    You're asking about sharpness but appying SMDegrain ?? Well it's difficult to have both. Or maybe you shouldn't denoise as much in the first place
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  9. Dot crawl filters usually work best when used before any other processing. The sample image you posted has been cropped and/or resized so I wouldn't expect dot crawl filters to work well with it (not to mention a single image only allows 2d processing). Also, dot crawl filters that work well with NTSC video often don't work well with PAL video.
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  10. Thanks everyone for help. Seems like TComb gives best result, but it adds very horrible defect to various parts on moving scenes, so checkmate does the work too, with no defects, but it still leaves some crawling.
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  11. Checkmate has some options you can fine tune. But it will create other artifacts if you crank it up too high.
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  12. Member
    Join Date: Sep 2007
    Location: Canada
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    tcomb has several options as well. Artifacts during moving scenes suggest you've set the temporal threshold too high

    dotcrawl filters tend to be very damaging to the other areas at the settings required to remove artifacts - you might consider limiting the damage with masks
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