creating insert on transparent background?

Serena wrote on 6/7/2007, 6:39 PM

I 'm sure this can be done. I want to create a stopwatch/start-lights clip to insert into a sail racing video. So I've composited this and it works quite nicely in cutting the image into the shots of boats manoeuvring for a start. It would be handy to have this insert in my media library, but I can't figure how to create this as stand-alone media for which I must have a transparent background (like "generated media"). If I render without the underlying main images I get the insert on black background, whatever variations I've tried.

Comments

richard-courtney wrote on 6/7/2007, 6:51 PM

If you render it as an uncompressed file such as AVI then use a custom
templete. (Choose Uncompressed for Video format) You'll be given
a checkbox to render alpha channel.

When you drag it into your project right click on the track to edit the properties.
The media tab has an option for Alpha channel. Default is none choose straight.
The clip should then show up with the checkerboard background. Whatever is
a higher (below it) numbered track will now replace the background.

Serena wrote on 6/7/2007, 8:34 PM

Thanks, that works exactly as wanted. Need to set stopwatch clip media properties alpha channel to "premultiplied" when I use it (or other than "none" setting, but premultiplied gives the best result). Or does this indicate I missed something in doing the render?

EDIT: we're chasing edits!! "straight" works too!