Fix artifacts

[girod2033]

Hello.
Can you please tell me, using this picture as an example, is it possible to fix artifacts?
An example would be nice.


Original.

[jagabo]

Was that deinterlaced with Yadif? Dots like those are often produced by Yadif. If so, try using a field matcher like TFM() instead.

If you're stuck with that as your starting point... The video isn't super sharp so a simple:

Blur(1.0).Sharpen(0.7)

will greatly reduce the dots without damaging the rest of the picture too much. Following that a little temporal noise reduction will probably take care of the rest.

If you want to preserve the grain in other parts of the picture try protecting them with something like:

b = Blur(1.0).Sharpen(0.7)
dmask = AbsSubtractY(src, b).ColorYUV(off_y=-8).ColorYUV(gain_y=10000)
Overlay(src, b, mask=dmask)

AbsSubtractY() is:

function AbsSubtractY(clip v1, clip v2)
{
    Subtract(v1.GreyScale(), v2.GreyScale()).ColorYUV(off_y=2)
    Overlay(last.ColorYUV(off_y=-128), last.Invert().ColorYUV(off_y=-127), mode="add")
}

dmask is a mask of the parts of the picture that were greatly changed by the blurring (adjust the threshold off_y value to get more or less pixels in the mask). The blurred video is overlaid onto the original, only where there is a big difference between the original and blurred videos.

There are other un-dot filters that may fix it (RemoveDirt, RemoveGrain, etc.) but one needs a video sample to test them.

[girod2033]

to jagabo,
It was messed up with the video by the Japanese Amazon again. I will try to download the source and make a sample.
Thx.