Dumb Question, But I'm Burned Out

Jay Gladwell wrote on 6/22/2007, 7:09 AM

Okay, I'm half way embarrassed to ask this, but this project has me so burned me out I can't even think straight.

I have a graphic with an alpha background. When I render that out by itself as an .avi file that alpha background will go black.

My question is, will I still be able to use that new file on the timeline and will the now black area retain its transparency? My guess is it will not.

The problem is the graphic stretches over so much of the film, timewise, I don't want to waste time rendering it to only find out it won't work.

Thanks!

Comments

farss wrote on 6/22/2007, 7:20 AM

You'll need to render to uncompressed if you want to retain the alpha channel.
If you want to render it as part of a composite it doesn't matter, what you see will be what you get.

Bob.

Jay Gladwell wrote on 6/22/2007, 7:29 AM

Thank you, Bob! I was unaware that the uncompressed files retained the alpha channel. I guess I'll have to give that a shot.

You learn something new every day.

rmack350 wrote on 6/22/2007, 7:53 AM

I like to say "You're forced to learn something new every day" ;-)

Rob Mack

Grazie wrote on 6/22/2007, 8:34 AM

Jay, I've been doing exactly the same thing today, with some titles I'm designing. It's the way I do 'em! Uncomped widescreen. I get black background and then I need to change the Media to Premultiplied (?) and it picks the black as transparent - done!

I've been doing this with massively long horizontal lower third credit rolling and it looks real peachy!

dand9959 wrote on 6/22/2007, 8:53 AM

I might be incorrect, but: I "think" the following would work....

Create a separate .veg that has one track that contains your original graphic (with the alpha channel).

Don't render.

Now, in your main project, include that .veg and place it on its own track. When you render your project, the alpha in the nested veg should be preserved.

Jay Gladwell wrote on 6/22/2007, 2:55 PM

Grazie, I was having a similar problem to what you described elsewhere here.

The project had over 25 visual tracks alone with a great deal of motion, going in and out of focus and minor animation. The seven and a half minute project took 6 days to render out to .mpg for DVD. Don't ask me what happened, but entire tracks and transitions were missing! It was a mess.

I divided the project up into logical segments and rendered out each one as an .avi file. Now it's rendering out the central segment where all the "fancy" stuff is. So far it's about 47% done after about six hours of rendering.

This has been a real head-banger for me.

Chienworks wrote on 6/22/2007, 3:38 PM

Just to add a bit to Bob's uncompressed advice ... uncompressed on it's own doesn't necessarily include the alpha channel. You have to manually select inclusion of the alpha channel when you start the render. Otherwise you won't get it.

If you don't have the space for a 32-bit uncompressed file then Quicktime also supports alpha.

Jay Gladwell wrote on 6/22/2007, 6:33 PM

Thanks, Kelly. That's good to know.