Can’t render out alpha in simple video file

I have a read node in Nuke with a .mov file which definitely has an alpha channel (an explosion).

The simple question is how do I export this from Nuke while maintaining the alpha channel?

I want to do this directly, in other words I have nothing else plugged into it, just want to render it out with alpha as a test.

It’s to then be opened in FCP, and I’m using Apple ProRes 4444 which is supposed to support alpha channels. I have tried PNG too which is the format the clip is originally in and that hasn’t been a success either. In FCP I make sure to change clip to ‘straight alpha’ in ‘item properties>format’.

^Despite this, I have no alpha channel after the render from Nuke.

I’ve tried many different settings of ‘premultiplied’/’auto alpha’ etc. and I get no joy.

I know/think it’s going to be something simple, but I just can’t see it!

If this test works, then I am hoping to key some footage with Primatte and export the footage with alpha for compositing in FCP, so this was meant to be a ‘simple’ test. Is it possible to do that – remove green screen and export the footage with alpha channel for direct overlaying in FCP?

Thanks for any help.

No Responses to “Can’t render out alpha in simple video file”

Post a Comment