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Setting a transparent composition background
I’m new to AE and am trying to do something that seems simple. What I’m trying to accomplish is create a composition with a transparent background, so that the rendering can be used in another editing program. The intent is to use the graphic motion strength of AE and apply the output as overlayed elements in another video editing system (Vegas Pro),
Imagine in AE, a rectangle positioned somewhere in the middle of the composition. After rendering, I want to pull the output video into another video editing system, overlayed onto existing video and still see underlying video around the rectangle. No matter what I try, the AE video gives a solid color for background.
I’m convinced I must be missing something fundamental – any help appreciated!
Thx
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4 Replies
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It is very fundamental.
In the render queue, make sure you set your output to something like Quicktime that supports an alpha channel. (The animation codec for Quicktime is quite popular). Make sure that it’s set to render rgb+. (That means rgb plus alpha.)Then what you render should work just fine in your editing program.
– The Great Szalam
(The ‘Great’ stands for ‘Not So Great, in fact, Extremely Humble’)No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.
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Hi Great Szalam!
Although that seemed to be the fix, I still must have something wrong.
I’ve rendered using the QT RGB+Alpha and am still seeing the composition’s background color covering my underlying video when imported to the other system.From my somewhat greenhorn perspective, it seems like there should be a way to set the background alpha to transparent, or turn it off completely. I’ve been searching for this, but getting the terms right is a little tricky
How do you make the surrounding background in a comp invisible?
I think that would solve it.Thanks again!
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Found the answer. Maybe this will help others importing After Effects into Vegas Pro:
Once you have the file in Vegas, right click on the footage and go to properties. Then select the “media” tab and go down to the field labeled “Alpha Channel” and select the appropriate option for the alpha channel…usually “Premultiplied (dirty)” works fine.
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if vegas would prefer a straight (unmatted) — perhaps call it ‘unmultiplied’ — render, that can be rendered from ae too. in the output module settings, choose:
channels: rgb + alpha
depth: millions+
color: straight (unmatted)for more info on this, check out aharon’s tutorial on the subject:
https://library.creativecow.net/articles/rabinowitz_aharon/straight_vs_premult.php
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW
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