need to make chroma key! omg

G

ghosttv

Carbonite Member
hi. I need to make a chroma for a testing. Can someone make a recommedation for best way to do? To the card its 420 color but how about mr. Ralph hdmi with avsyth scrip? That's already 422? I still have no black magic. But its worth of it if the key will be awsome!!! If I can't use hdmi, its matter which codec? Is the mjpeg work any better than avchd? Any advises? Lol!
 
ghosttv said:
hi. I need to make a chroma for a testing. Can someone make a recommedation for best way to do? To the card its 420 color but how about mr. Ralph hdmi with avsyth scrip? That's already 422? I still have no black magic. But its worth of it if the key will be awsome!!! If I can't use hdmi, its matter which codec? Is the mjpeg work any better than avchd? Any advises? Lol!
Click to expand...

Although I'm a big fan of recording HDMI, the fact is I've pulled excellent greenscreen keys from the GH2's AVCHD, both at 24P and 60P.
Before you go down the HDMI path, I would encourage you to run your own tests with AVCHD and see whether that works for you.
 
I have compared chroma keying with GH2 AVCHD 1080/24P, Sony EX1 XDCAM native codec and 4:2:2 taken from Sony EX1 SDI output.

The result surprised me: GH2 AVCHD 1080/24P was consistently BETTER that Sony EX1 XDCAM native codec and definitely NO WORSE than 4:2:2 taken from Sony EX1 SDI output.
 
Omg! Mr saveli I so confuse about that! I was always got idea that more color information make a better key! Amazing that somehow avchd with only 420 can beated sony ex with huger sdi feed tube. Can anyone esplain those result? It because big sensor? Codec? Lol!
 
pulling a good key isn't all about colorspace, but also greatly affected by how well the edges are resolved by the codec/camera. if you have a good clean edge against your green backdrop, you should be able to pull a decent key.

just test for yourself and find which film mode and format give you the best results.

most of your effort should go into lighting. the camera side of the equation will only account for 10% of the final result.
 
Also your editing tool matters. I could not get a good key from Vegas out of the box. I ended up trying/buying Boris Continuum which has a very good keying tool. Has better edge wrap, etc. I haven't tried the native keying on FCP yet.

My camera is an HMC150 doing AVCHD. While I don't consider the output 'professional' the client was thrilled, and decided to do all the future shoots with green screen. So I'm happy. I'll get better with it over time, no doubt. And I plan on trying it with my 7D to see the difference.

You can view the output at
http://www.youtube.com/watch?v=6Afw6TtCWI4
 
yes, good point.
i get the best keys using After Effects' Keylight. i did a greenscreen shoot recently using GH13 mjpeg 4:2:2 and keying wasn't much more than one click of the mouse!
 
Also helps to have sharpening turned down to avoid edge artifacts - and remember that sharpening set at 0 is not the same as OFF - much better results at -2.
 
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