Problem with After Effects, On2 Codec and Alpha Channels

Hello,

I've been having this problem for some time now, and after hours of trying, I still don't know what to do - I hope you can help. Besides, I have seen this asked several times, but none of the answers seem to work.

Whenever I import any quicktime video compressed with the On2 codec (I believe this doesnt only happen with On2) into After Effects, I get the alpha channel dialogue:

"clip.mov has an unlabeled alpha channel:

ignore.
Straight - Unmatted
Premultiplied.

Guess"

Whatever option I choose, I get a white screen instead of the clip.

What am I doing wrong?

 

It's the codec causing the white screen, not the alpha channel. A lot of people have that white-screen problem with On2, that's why a lot of people don't even bother using it.

Just about every 32-bit image or movie you bring into AE will pop up that dialog, since most image formats leave the alpha channel "unlabeled".

Is this 3D footage in On2? What's the purpose of the alpha channel?

 

Yes - It is 3D footage compressed in On2, but I didnt mean to have any alpha channel on it, and it happens with anything captured in On2, so I suppose you are right and it's the codec.

 

I don't compress 3D footage at all, myself. I always render as a sequence of uncompressed TIFF files. And I'm usually careful to only include the alpha channel when it's needed. If you do include the alpha when you don't need it, just choose "Ignore" from that pop-up menu, and it'll treat it like a 24-bit image. Unless you've got a wacky codec like On2.. hehe.