Comments

farss wrote on 9/9/2003, 10:19 PM
You cannot unless the scene you want to change is all one color, preferably green or blue. ALternative is to create a mask but that is a lot of work potentially. Search the forum for heaps of info on Chroma Key.
pb wrote on 9/9/2003, 10:32 PM
I don't know about the rest of you but I have found DV/DVCAM does not chroma key all that well. Certainly not as easily as Beta. Maybe the screen colour affected it but even after buying the latest version of Ultiamatte for the AVID Media Composer it still had artifacts around the on cam host. We use two banks of flourescent lamps against a proper green backdrop and backlight. Doesn't help so I will have to hang on to my BVV5s for a while yet.

Peter
rmack350 wrote on 9/10/2003, 12:38 AM
I'm told that it's possible to get a good key in DV.

The pitfall is the 4:1:1 sampling (or 4:2:0). color is sampled every 4th pixel and then calculated in the space between. This makes for smeary color. To illustrate this add colorbars to a project and then render the bars to a new track. Compare the two. What a mess.

Digitized Beta (Not talking about digibeta) is usually captured in 4:2:2 space and the key can be a little sharper. I suppose that if you use the same footage in Vegas and render to a 4:2:2 codec then Vegas might pull a better key.

Rob Mack