Mister Hatt wrote:No? Spline36 is the best to use, unless you don't have any idea what the numbers do, in which case use whatever looks nicer to you when you write it.
I ran some tests about:
original image, I choose something hard to scale down and keep sharp:
Then, I have resized the image to 171x171, that is the same rate when you scale down from 1080p to 720p, using Spline16, here the result:
and finally, I resized the original source using Spline36:
What a wonder! I can't tell any difference between the two resized images (but see the huge difference from source: light circles are totally misplaced!), and Spline16 taken 3 times less cpu to resize. This maybe can save the day if your pc is not high end and you wanna encode 2 hours of HD video there.
Personally, maybe because I also studied the math behind all of this, I was expecting Spline36 performing
worse than Spline16, because it was taking more samples than really needed to scale an image down to 67% of original size. That was the purpose of my first post.
At the end, just to avoid confusion about what filter is "the best" about resize, truth is that doesn't exists the best filter. Any filter has his own good and bad things, it is your experience and knowledge of what you are doing, to let you choose the correct filter for your resize purpose.
Wanna go ahead the cubics?
Here some hints.
(scaling 1080 to 320, more often, and spline36resize works like a charm 
)
