Builder and mask

I’ve got some troubles with Sapphire Builder in Media Composer 2020.12.3.
On V1 I’ve got some background video.
On V2 is a S_Pan&Zoom effect that is set to display an image. It does not fill the frame so there’s black around the image.
Then I alt-drag S_Builder to V2. I set Mask to “This layer”; mask from Alpha - and background to “1st below” and now I can see the background video below my image.
So far so good!

But if I open builder and look at the Mask node it’s empty. No image and no alpha.
Is this a bug or am I doing somthing wrong? Any ideas appreciated :slight_smile: :slightly_smiling_face:


PS. This is Sapphire 2021.5

Hi Kåre,

Avid doesn’t have true Alpha Channel support for layers so this workflow is not going to work. Your best bet is to cheat it with your own white and black custom mask set on a track below and point to that. Hopefully this is an easy shape that you can make or import! So, you would have v3 Builder/PanZoom, v2background, v1 custom white/black image that acts as the mask.

Hope this helps,

Hi Brian,

The funny thing is that it does work - in that way that the s_effect “sees” the alpha from s_pan&zoom and makes V1 visible behind V2.
Alpha is just not accessible within s_effect but seems to be applied “downstream”.
Would it help if I make a screen recording of this?