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Chroma Key and Flash production
When shooting a subject in front of a green screen, is it demonstrably beneficial to upgrade to an HD camera when the final product will be rendered as streaming Flash content?
My main question is whether the added pixel depth that HD yields will helps us cut a cleaner key than SD will by reducing problems with aliasing. But I do wonder whether the added investment in the upgrade to HD will matter much considering the nature of the final output.
Thanks in advance,
Carl
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7 Replies
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I shoot a fair amount of green screen. I went from a Canon XL2 miniDV to a Sony HVR-V1U HDV camera and I’ve been amazed how much easier it is to get a good key. In production, the lighting is easier, more forgiving of unevenness and wrinkles. In editing, the edge is sharper, less jaggy. My final endproduct is usually Flash (or .wmv) as well, but starting out at higher resolution has really made things easier for me.
Mary Waitrovich
UW-Madison -
HD or HDV will give you alot better keys than DV as DV’s color space 4.1.1 is very unforgiving with chromakeying. With DV I always put a chromablur effect just before the chromakey and set it to medium. This helps tremendously with DV keying. Plus if your subject is taller than wide, rotate your camera 90 deg and make use of the more vertical lines of resolution. Danny Hays
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Thanks, everyone. I really appreciate the feedback.
Carl
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A follow up:
What do you think the recommended specs should be for an HD camera that is used to produce the source material for green screen? Again, we’re looking to stream the output as Flash, with a frame that is 600 X 800.
One of our corporate papers suggests an HD camera that produces an image at 1920 X 1080, but I have to wonder whether or not this is excessive.
Carl
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Your corporate papers are correct. HD comes in two flavors 1920×1080 and 1280×720. You’d be hard pressed to find a camera that shoots 1280×720 anymore. It was an early format that hardly anyone is shooting. 1920×1080 is what you want.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thanks very much for the info on resolution. I wasn’t aware of the uniform change in HD resolution standards.
One wonders what features you’re actually paying for that justify an expense in a camera that costs in excess of $6000 as opposed to one that is closer to $1000. I know that when you’re graduating to a “professional” class of camera, you’re paying for different media such as DVCAM, etc. But for chroma key images that are ultimately streamed in Flash, I still find it hard to justify a potential $6000 expense, as some of our corporate literature suggests.
Carl
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It’s not so much a change in standards. Both are still standards and cable HDTV is primarily 1280×720 still because it takes up less bandwidth and 720p HDTV’s are selling great because of the lower cost than 1080i. It’s just that all of the new cameras are shooting 1080.
Nothing says you have to buy a $6000 HD camera. The Sony HVR-A1U is $2200, only $1899 at B&H after rebate and it shoots perfectly fine 1080 HDV that works great for chroma key. In general any HD camera will give you 5 times the resolution of DV. If you saw the picture you’d understand. That’s the only way I can explain it. Anyone who believes they can uprez DV to HDV simply doesn’t understand how much more information is in an HDV picture that is simply not there in DV. You could never get HD details from uprezing DV and it’s the incredible detail that makes chroma keying easier with HD.
~jr
http://www.johnrofrano.com
http://www.vasst.com
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