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After Effects - Output Alpha still renders background colour

Posted: Sun May 05, 2019 02:43
by hasher22
Hey guys,

I have AE v16.1.1 (build 4) and the DXV 3 output installed.

Every time I render out a composition on settings:
- DXV 3
Video Output
- Normal Quality, With Alpha
Channels: RGB +Alpha
Depth:: Millions of Colors+
Color: Premultiplied (matted)

The background colour renders with it. I had my background colour to a lime green colour. I have toggled the transparency grid in AE and yes the checkered pattern shows and the lime green colour disappears. I know the background should not be rendered with the setting alpha. I have no solids either in my comp.

Hmmmm?>

Re: After Effects - Output Alpha still renders background colour

Posted: Tue May 07, 2019 02:15
by francoe
I think DXV has no chance to screw up things on that side, is just AE.
Check if you're rendering with Premultiplied (matted) instead of straight alpha.
I bet you're premultiplying by lime, tasty but wrong for alpha creation. :mrgreen:

Re: After Effects - Output Alpha still renders background colour

Posted: Tue May 07, 2019 08:41
by Joris
How does the background color factor into premultiplication when alpha is zero? Zero times lime is still zero.

If you're seeing lime where there shouldn't be lime, my guess is you are rendering straight and interpreting premultiplied.