blur math…

[Kevin Camp]

i haven’t timed blurs, but by its name, fast blur may be the fastest. in addition it has an option for repeat edge pixels which can be pretty handy.

Kevin Camp
Designer – KCPQ, KMYQ & KRCW

[Kevin Camp]

additionally gausian blur and fast blur both support opengl acceleration, if your graphics card is supported by ae (go to the previews pref and click opengl info, ae will say what is supported by your card).

if it is supported, enable opengl, set to accelerate effects with opengl, and then you need to set your render settings to use opengl for final render. to make a render setting preset (from the render queue) select make template from the render setting pulldown. give it a settings name, like opengl (you can even pick it as the movie default until you’re finished rendering if you’d like). click edit… make sure the settings here are what you want (they should be based on your current default movie setting, usually ‘best settings,’ then check ‘use opengl renderer.’ hit ok twice and if needed use the render settings pulldown to use your new render preset (template).

note, if you are using an intel mac, apply your opengl blur on an adjustment layer, other wise ae will crash as soon as you apply it.

now you’ve offloaded the bulk of the processing from your cpu to your gpu.

Kevin Camp
Designer – KCPQ, KMYQ & KRCW

[Darby Edelen]

Box Blur is usually the best to use, it gives you control over how render intensive the blur is. At 0 iterations it looks pretty Boxy (true to its name) but at 3 it looks about like a Fast Blur. It gives you an extra level of control (specifically how accurate vs. how render intensive the blur is).

[Chris Zwar]

This blog is interesting:

https://prolost.blogspot.com/2006/03/tale-of-three-blurs.html

But there are also 3rd party blurs which are fast too… I’ve been using the Tinderbox T_Blur for years and the old Composite Wizard Super Blur is very fast too. I’m sure that the Boris and Sapphire blur algorithms are highly optimised as well.

Composite Wizard (which is old and has been replaced by a completely new product by the same programmer) came with a thick manual that had a whole chapter explaining the difference between box, gaussian and camera blurs. Unfortunately I don’t have it any more…

-Chris