Chromakeying in Vegas

MrMikeC wrote on 2/18/2004, 1:54 PM

Hi all,

I'm going to attempt to try some chroma key stuff in Vegas. What I'd like to know is if I want to replace the background behind the person I'm shooting with a still image, what should the resolution of that image be so it looks good in the end?

Thanks,
Mike

Comments

Spot|DSE wrote on 2/18/2004, 2:12 PM

Depends on whether you are zooming in on the image or not. If not, and it's at least 655 x 480 in origin, then 72 dpiis fine, most of our non-zoomed stills are done at 90 just to have a little extra clarity.

MrMikeC wrote on 2/18/2004, 2:14 PM

why 655x480 instead of 720?

Chienworks wrote on 2/18/2004, 2:24 PM

Because that's what it should be.

Of course, you'd probably like more of an answer than that. ;)

DV pixels are rectangular, slightly narrower than they are tall, in fact 0.90909... times as wide as they are tall. Still image pixels are square. So, multiplying 720 x 0.90909... is 654.545454... which means that the shape of the DV frame is 655 (about) / 480 times as wide as it is tall. If you want to fill a 655x480 rectangle with square pixels (which is what still images use) then you need a 655x480 image.