Digital Matte Extraction (blue/green screen) with DV?

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I'm currently into computer graphics, created with 3d graphics packages and exported to avi format. Recently, however, I decided to learn a little bit more about digital compositing -- live action with CG. I got really excited about all of the possibilities of digital matte extraction until I found out the color compression ratio of the dv standard. Has anyone had any luck chroma-keying with dv, or is there too much compression? Any thoughts would help.

Also, I've read a lot about the Canon XL1's 30 full frames-per-second mode, yeilding more "film like" results. I'm interested in this feature because it allows for better looking CG integration. I've ruled out the VX1000 because it can only handle 15 fps with it's progressive scan feature, leaving the Canon as my main choice. However, I've read that using the XL1's film mode has a big drawback: Any quick movements result in blocky motion (tilts, quick pans). This could be a problem, as I plan to do some action shots which would involve quickly-moving bodies (people's :)

In short, I'm fairly new to dv, and I need some help before I make a $4000 decision -- thanks.

-- Erik Bakke (ejbakke@students.wisc.edu), July 01, 1999

Answers

DV works fine for blue screen.

Ignore the people who say you can't get good mattes from DV originated material. If you are using a 3 chip camcorder, you can achieve excellent results, if you either digitize in analog component output, or input your video through the firewire port.

The chroma resolution is an issue yes, but that is like saying CD recordings are bad because they aren't digitally sampled at 48khz. I've done it, and it works fine. Remember, DV as a recording format has better chroma resolution than betacam, which people have been successfullly creating mattes from for a long time.

More important is the quality of the camera you are using, and the signal to noise ratio. But a VX1000 works just fine.

-- Steven Bradfod (bradford@seanet.com), July 05, 1999.


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