Live Video - Blend Mode

Hello there

First of all I would like to thanks Brad, your framework is incredible in both ways (Performance and easy to use). I figured out and confirmed throughout Brad's iTunesU videos about the experimentation with Quartz Composer.

My current problem is that I have develop a desk of filters and effects that need apply in 2 ways from the same video input and merge it for render. For example, like in Photoshop, get 2 layers and apply multiply blend mode to the top one. I would like to achieve this with GPUImage, but from what I understand blend modes are for still images or image files right?

Thanks in advance and sorry for my english.

Cheers