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View Full Version : What is sharper LanczosResize, Blackman or Lanczos4?


php111
19th July 2008, 20:32
Hi,

What is sharper and a better resizer?

1.) BlackmanResize

2.) LanczosResize

3.) Lanczos4Resize

Ranguvar
19th July 2008, 22:34
Try and see!!

I would also try the Spline resizers (Spline16, Spline36, Spline64).

Zwitterion
20th July 2008, 00:14
from soft to sharp (according to my experience):

Bilinear
Bicubic(b=1./3, c=1./3)
Spline16
Bicubic(b=0, c=0.75)
Spline36
Blackman(taps=4)
Spline64
Lanczos3
Lanczos4

However, sharper is not always 'better', as ringing increases too. I wouldn't use anything sharpen than Spline36Resize.

Ranguvar
20th July 2008, 00:44
I saw a post in the Spline thread with a comparison to Lanczos4... Spline36 seems to be slightly sharper and has slightly less ringing than Lanczos4.

And I believe Blackman can get even sharper than Spline...

Again, the best way is to test and see for yourself.

php111
20th July 2008, 00:47
Thank you everyone for the replies.

Avenger007
20th July 2008, 01:12
If you want to try an experiment...

FUNCTION Focus(clip input, int clp_width, int clp_height)
{
# May help some edge blurred sources by defining the edges
ssx = 3.5
ssy = 3.5

# Supersize the clip ensuring its mod16
xx_ss2 = int(clp_width * ssx / 16 + 0.5) * 16
yy_ss2 = int(clp_height * ssy / 16 + 0.5) * 16
input = input.LanczosResize(xx_ss2,yy_ss2)

# apply our transfors to the edges (blur, warpsharp (only to luma), and xsharpen)
input = input.removegrain(20)
input = input.awarpsharp(depth=10, thresh=0.5, blurlevel=2, cm=0)
input = input.xsharpen(255,255)

# return the clip in its original size, this will just have enhanced edges
RETURN input.Lanczos4Resize(clp_width,clp_height).RemoveGrain(mode=1)
}

In the Focus(...) function of MC_Spuds, try different resizers and compare their sharpness.
The image is supersampled by upscaling to 3.5x the original size and sharpened, then downscaled to the original size.

Performing this experiment with Lanczos vs Spline shows a noticeable difference, with Lanczos being sharper than Spline.
However, I use Spline64 because it's still sharp and easier to compress by the encoder.

backtohell
20th July 2008, 09:14
i usually prefer slightly more sharpness in my videos so my choice is either Lanczos4 or Spline36, but never heard of Blackman?

Gavino
20th July 2008, 09:40
i usually prefer slightly more sharpness in my videos so my choice is either Lanczos4 or Spline36, but never heard of Blackman?

BlackmanResize is available in Avisynth v2.58. To quote from the documentation (http://avisynth.org/mediawiki/BlackmanResize):
BlackmanResize is a modification of LanczosResize that has better control of ringing artifacts for high numbers of taps.(taps equates to the 3 or 4 in Lanczos3, Lanczos4 and the default for LanczosResize is taps=4).

backtohell
20th July 2008, 14:41
Thanks Gavino for the details on BlackmanResize

will give a shot