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Minister OI

08-04-2005 07:58 PM

KVCD: Resizing artifacts?

Hi All,

When resizing downward (ie: 544, 528, 352 x 480) in mpeg2 from DVD (720x480) material, the smaller you resize, the more these "lines" appear slicing along edges. More so along straight edges, but still noticeable around other shapes as well (faces, clothing, etc)

It seems like this is inherent when downsizing the image, but I was curious if there is any type of filtering that directly addresses this to attempt to soften it without loosing the clarity of the rest of the image.

I know using bilinear resize softens things, but of course it does that to the whole image, which I am trying to avoid if possible.

Anything out there that might help with this?

Thanks

kwag	08-04-2005 09:45 PM

What you are refering to, is the "stair case" effect on the edges.
The only thing you can do, as you said, is use bilinear resize, or other filter to smooth out the picture.
Sadly, there's not much you can do because the effect is caused by the resizing ratio.

-kwag

Minister OI

08-04-2005 09:54 PM

Ah damn.

Thanks for the info Kwag. Much appreciated.

:)

Dialhot

08-05-2005 03:09 AM

There are new resizers in avisynth 2.56 to play with. Try them.

Code:

Spline16Resize (clip, int target_width, int target_height)

Spline36Resize (clip, int target_width, int target_height)

GaussResize (clip, int target_width, int target_height, float "p")

Minister OI

08-05-2005 03:07 PM

Not a bad idea at all. I am using the newer avisynth as well.

Will give a few tests in a litte bit and see what results I come up with.

Thanks Dialhot

:)