Blur just the FG in a basic key comp in Avid

I have a bluescreen (V2) keyed over a background (V1) using Spectramatte inside a 3D Warp. I just want to blur the FG element on V2 - I add a Fast Lens Blur to the clip but it blurs the BG as well. There is a Apply to Title-Matte button which I thought might work but it doesn’t.

I then did the key again using Primatte which I thought might help. Same deal, I can’t get the blur to only affect the FG and when I hit the Apply to title-Matte button the FG disappears.

What am I missing?

Perhaps a tutorial might help? Anyone know of any?
Any tutorials I’ve seen never have additional effects added…its always just using extra parameters within the effect.

Hi Mike,

Can you please provide some information on your system? In particular, what version of Avid are you using, what version of BCC are you using and on what OS are you using it.

I would suggest using BCC Primatte instead of Spectramatte for the key - it’s a much better keyer and works better with filter stacking, which is what you want to do.

So let’s say you have BCC Primatte on the layer with a live key. To add the BCC Lens Blur to that layer only, you need to hold down the option/alt key while dragging the BCC Lens Blur on top of BCC Primatte. Then, because you are in essence compositing multiple filters on a clip, you need to set the proper compositing order in the filters. To do that, in the Primatte filter control panel, set the Background pop-up to none, then in the Blur filter control panel, set the Background pop-up to 1st below. And that’s all there is to it. :slight_smile:


Hi @PeterMcAuley

Sorry for the long delay in responding. This seems to work.
I was playing around with the Background options, along with changing the Primatte output to Final Matte and attempting a 3 layer Avid matte comp. What threw me off was changing the BG to None means the effect disappears. I presume choosing None means the alpha channel gets passed the effect above it, and the effect above then takes responsibility for comping the element onto the BG? Does every effect in BCC have this Background dropdown chooser?

Hi Mike,

Most filters in Continuum include the background compositing feature and can pull video up from 2 tracks below the filtered track.

Setting the background to none instructs the filter to finish the composite that that stage and to ignore any layers beneath it in the timeline, unless otherwise directed by a filter above it in the stack.

I hope this helps!