Not Outputting Alpha Channel
by Caleb Armstrong
on
Nov 4, 2008 at 7:43:31 pm
For some reason AE isn't outputting an Alpha channel when I render. I've got it set up to render with "RGB+Alpha" but every time that I render out and throw it into my FCP timeline I get a flat black background. All that I have are a few animated circles - nothing major, I don't even have a black solid in there anywhere.
Re: Not Outputting Alpha Channel by Caleb Armstrong on Nov 4, 2008 at 8:07:48 pm
I'm using the animation codec. I haven't changed my procedures at all and I've never had this problem before which is why I'm so befuddled as to what I'm doing wrong.
Re: Not Outputting Alpha Channel by Caleb Armstrong on Nov 4, 2008 at 8:52:03 pm
Nope, the Alpha type is set to straight. Pixel AR wouldn't have anything to do with it, would it? If the sequence settings between the clip and the FCP sequence weren't the same would it affect the alpha?
Re: Not Outputting Alpha Channel by Dave LaRonde on Nov 4, 2008 at 10:14:59 pm
I'd double-check that you have transparency in your comp. There's a switch to view just the alpha channel below the comp window. All-white means total opacity, and there's something amiss in the comp.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: Not Outputting Alpha Channel by Caleb Armstrong on Nov 5, 2008 at 5:01:04 pm
Thanks for the heads up on the switch, Dave! I checked it and everything seems correct. The elements that I need to be opaque are white, and what I need to be transparent is black. It's still not outputting the alpha.
I'm still convinced that I'm doing something wrong though and that this isn't just some bizarre thing.
Re: Not Outputting Alpha Channel by Dave LaRonde on Nov 5, 2008 at 5:27:02 pm
So you've set EVERYTHING you need to set to get an alpha channel?
- A codec that supports alpha channels?
- Millions of colors+?
- RGB+Alpha?
- Straight/Premultiplied set properly for the next application that will use the rendered file?
- Rendering in the Render Queue and NOT simply Exporting?
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: Not Outputting Alpha Channel by Jason Milligan on Nov 5, 2008 at 8:20:45 pm
Premultiplied may be the issue if FCP is reading it as straight.
I believe the setting in FCP is called "color" when using premultiplied footage from AE.
Have you tried using that setting?
Re: Not Outputting Alpha Channel by Caleb Armstrong on Nov 5, 2008 at 9:12:37 pm
Hmmmm. . .I'll have to try that. I've experimented with rendering it out as premultiplied and straight and it still isn't working. I'm willing to be that I accidentally clicked something when I was setting up the project on either the AE or the FCP side but I just don't know what it could have been.
Re: Not Outputting Alpha Channel by Caleb Armstrong on Nov 7, 2008 at 6:42:11 pm
I chucked the old composition and started a new one and everything seems okay. I'm starting to think that I may have been working in 8bpc but I didn't check before I trashed the old comp.
Thanks for all the input guys, it was really appreciated! Keep up the good work, you guys do a hell of a job here.
