Resize Filters

[WILLIS]

I did a search for this but could not find a definitive answer so I thought ide ask. What are the good internal and external resize filters for upsizing and image and downsizing as well. Thank you.

[shoopdabloop]

I prefer to use Gauss or Bilinear, as they are halo-free.

But I believe Spline16/36 is the "middle ground" for sharpness vs haloing vs softness.

[thetoof]

http://forum.doom9.org/showthread.php?p=1366939

Even if the answer is not definitive, it's always good to concentrate discussion in an already existing thread when the topic is exactly the same, especially when it's so recent... easier to ref to afterwards & usually ends up reaching more people.

Oh, and welcome to the forums ;)

[10L23r]

for downsizing:
use bilinear if you are constrained by bitrate/filesize. bicubic works too.

use spline36 or lanczos otherwise. i personally prefer lanczos... other people prefer spline 36, but the difference between the two is negligible. lanczos is very slightly sharper and halos slightly more.

for upsizing:
if upsizing by <50%, then use spline/lanczos
if upsizing by >50% use nnedi2 if you have enough time or your cpu is fast enough. otherwise just use spline/lanczos

[shoopdabloop]

Quick question: if something like this (http://www.korf.co.uk/spline.pdf) were put in 2D and used as an image resizing filter, would it be a good filter?

[10L23r]

it could possibly be useful for upsizing certain types of content but nnedi2 would probably beat it in that case...

I suspect the result to be somewhat similar to gauss or lanczos with 1 tap