Katie Boundary
3rd September 2017, 06:54
A few months or years ago, I was playing around with different settings for cubic filters and noted that despite the "B+2C=1" rule, the cubics that gave the best overall results seemed to be at about b=0, c=1.
Today, I was playing around with filter shapes in Desmos and noticed something very peculiar: at x=1, the tangent of a raw sinc function is -1, and the tangent of a b=0, c=1 cubic is ALSO -1. This is also where both filter shapes are at their steepest. That's the reason why cubics start to look like ass beyond c>1: the filter shape gets "too steep" (defined as steeper than raw sinc) at x=1.
Today, I was playing around with filter shapes in Desmos and noticed something very peculiar: at x=1, the tangent of a raw sinc function is -1, and the tangent of a b=0, c=1 cubic is ALSO -1. This is also where both filter shapes are at their steepest. That's the reason why cubics start to look like ass beyond c>1: the filter shape gets "too steep" (defined as steeper than raw sinc) at x=1.