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Export matte in after effects composition (used roto brush) – to use in final cut pro 7
I used the roto brush to remove the background from my subject in after effects and now I want to use that clip in Final Cut Pro 7.
What settings? I tried ProRes422 because (I think) it exports with an alpha channel. In fCP7, I changed the clip’s alpha channel to straight.. The background isn’t transparent.
Do I need to make it transparent in After Effects? How? Is the composition what I should export, or.. layer..
Help!
Thanks—————————–
OK, I realized that prores422 doesn’t have an alpha channel. I was thinking of prores4444. Its exporting now.If there’s any other settings I should be aware of, any recommendations would be great!
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4 Replies
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Ok… that didn’t work…
I am getting a message when I render out that color depth exceeds project color depth. Is that the problem somehow?
In Output Module, in the Color area, should it be “premultiplied” or “straight”. I had it on straight before.
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Hi there,
First of all, make sure that the Rotobrush has created the transparency you want by clicking on the transparency grid in the comp panel. You should see the grid where there is transparency. You can also use the Channel menu to view the Alpha before exporting.
Secondly, Prores 444 codec works with Trillions of colors so you need to be working in a 16 or 32-bit project to render that color depth. 8-bit’s won’t cut it I’m afraid, only Millions of colors!
Alternatives to try if you’re staying in an 8-bit project are the Animation Codec and the PNG codec, both of these render with Alpha and are lossless codecs.
Hope this helps.
cheers,
Angie
Angie Taylor animation & illustration for television, film, web and devices
https://www.angietaylor.co.uk
Twitter: theangietaylor
Linkedin: theangietaylor
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Thanks for the tips Angie.
Helpful to know about how to check Alpha, but I’m still doing something wrong. In the Composition tab (large center part..), I see my background is a grid with white and grey squares. I’ve checked the Channel menu that shows my image in white and the background (empty part) in white.
So it looks like my Composition has the right Alpha. I exported as animation codec and I didn’t get the message about color values exceeding project’s color values.
I’m thinking it must be something in FCP7 to do with the Alpha channel of the clip. Maybe I need to post this in the FCP forum. Do you know FCP stuff Angie? (I’ve changed the alpha in “item properties” of the clip to “straight” but no luck.)
Anyone have advice or tips of how to.. tell FCP that there’s an Alpha channel?
Thanks!
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Just a note for any others who happen upon this thread, as I did…
ProRes 422 does not support an Alpha channel. ProRes 4444 does support an alpha channel, which is what the extra “4” at the end stands for.
I think the problem above was in exporting to a format that did not support an alpha channel in the first place.
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