Alpha Channel for Drawing Recorder

[hilary]

Hi All,
So I have done this before and now I can't seem to do this again. I want to export the drawing I have recorded with the BG so that it can me comped over some live action. I draw on a separate layer render without the BG (it is turned off or not there at all)and it still seems to sandwich the two together I have also tried all the export settings too with no result (ie pre- multiply). What am I doing wrong here?
Cheers,
Hilary

[Paul Fierlinger]

The easiest way to find what you have missed if you uploaded a screen print of your export panel. Can you do that?

[hilary]

Hi Paul -
So I pulled up my old file that worked and compared the two (see jpeg below) The new file won't seem to allow me to get rid of the BG. Not on the rendered clip anyway - it will on the still clip but that's still. Again I am sure its something simple...
Cheers,
Hilary

[Paul Fierlinger]

My first guess is that something happened to your codec. Which one have you selected? Have you tried AVI (Internal) Motion-JPEG.

[slowtiger]

Did you, during recording, had your TVP background set to transparent?

[hilary]

no I didn't because I am writing with black. But I just tried it writing with white with no BG on when recording and it worked on the export - but this can't be the only way no? What if you have a reference layer underneath. Paul I tired the MPEG codec that didn't work either..generally I find that I have hit a miss results with Motion Jpeg..Anyway thanks as always I have converted my white letters to black in AE and will just export from there for now.
Cheers,
Hilary

[slowtiger]

no I didn't because I am writing with black. But I just tried it writing with white with no BG on when recording and it worked on the export

So you expect TVP to somehow guess that you want a transparent BG although you didn't use a transparent BG?

[Paul Fierlinger]

You can use the Light Table's ability to carry off peg images as a guide. It's just a virtual image on the first frame.

[hilary]

No I thought the recorder would be recording that layer only - I hid any extra layers I had and turned off the BG when I went to render the recording - I thought this would work.

[Paul Fierlinger]

I just tried what I wrote above. I drew an image on a layer with just the first frame. I made a new frame after that, turned on the checkered background, turned on the Light Table, turned on the off peg feature for the first image,which now appeared on my frame, drew a black image, turned on export panel, turned off BG, and there was my image against an alpha bkg. If you would use a live action frame on the first frame, you could use even that as a guide.