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chroma key with HDV or HD footage
Any advice or concerns I should have about the following chroma key situation:
I’ll be shooting on a Sony PMW EX1. I was planning on the HDV format, but I can shoot HD. The client wants a blue/green screen. And, of course, I’m editing on Final Cut Pro 6.0.4. -
16 Replies
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Sounds good to me, but obviously when keying choose the option with the shooting option with the least compression!
danny greer
dallas, texas
http://www.dannygreer.com -
Based on some headaches my friend once had doing this, be sure you standardize all the footage to the one same codec, shutter, and frame rate, etc. so there is no need to transcode and everything stays native. The friend had major issues mixing 24 p and 30 fps footage in the compositing, eventually had to transcode the oddball elements first.
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[Lawrence Robbin] “I’ll be shooting on a Sony PMW EX1. I was planning on the HDV format, but I can shoot HD.”
You can shoot HDV on EX1’s? I didn’t know that. Anyway, I’ve done plenty of keying of XDCAM EX footage and it looks fine. Generally anything shot progressive is a bit easier to key, expecially if there’s movement in the frame. Keying in After Effects using Keylight is pretty amazing judging from the tutorials I’ve seen of it – not used it myself as we have the older version of AE. The chroma keyer in FCP is acceptable if you don’t have After Effects.
The trick is in the filming really. If it’s lit nicely you’ll be fine. Maybe check on the Cinematography and XDCam forums for advice on shooting/lighting if it’s something you’ve not done before. -
First off, HDV *is* HD. HD is standard, HDV is a format. Secondly, using an EX1 and the XDCAM EX codec should yield a better result than a comparable HDV camera.
[Alex Elkins] “You can shoot HDV on EX1’s? I didn’t know that”
SP quality on the EX1 is HDV.-A
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I would assume HDV is even worse at keying than regular DV since it’s 4x the resolution at the same bitrate 25mb/sec.
DV is pretty horrible for keying. Shoot the regular HD vs. HDV if you can.
Bret Williams
Web Design . Motion Graphics . Video Editing
http://www.bretwilliams.com -
someone told me about this a couple days ago
https://www.dvgarage.com/prod/prod.php?prod=dvmatteb
they said it works really well for HDV and DV footage. I’ve never used it before as we don’t use HDV or DV footage.
-mattyc -
Regardless of the keying plugin you use, make sure the light on the green screen is completely even across the screen and it’s not hotter than 50 units. Use a waveform monitor! That will make keying much easier during post.
John
MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.4 QT7.5 Kona 3 Dual Cinema 23 ATI Radeon HD 3870
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24″ TV-Logic Monitor
Final Cut Studio 2 (up to date)Pro Tools HD w SYNC IO, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN
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I recently had my 1st go at keying having shot on DV. As time was short and my knowledge limited, I opted for the DV Matte Blast plug-in ($99) which works on Final Cut and Motion. It’s ideal for compressed footage for a quick and respectable key.
But in general, I think After Effects is your best bet for keying. Or if you’ve got money to buy a plug-in, and like me, are only familiar with Final Cut and Motion, a great keyer i’ve seen used is Primatte Keyer Pro 4, which gives great results.
https://www.redgiantsoftware.com/products/categories/keying/primatte-keyer-pro/
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Thanks!
To summarize the advice so far:
– Select HQ 1080/30P as the preferred Video Format
– Be sure to light the green screen evenly – no more than 50 units
– (I don’t have AE therefore…) try chroma keying with FCP and if there is a problem use a keying product called DV MatteLR
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Also use zebra bars to check evenness. I don’t agree 50 IRE is the “magic” number, I like it a bit hihger than that, but anything between 50 and 70 should work fine, if its even. You don’t need it brighter than everything in the frame, is my main point, you want saturated chroma, not screaming luma.
I’m doing pretty well keying Dv25 in FCP6 using just the FCP keyer, but can’t wait for them to install my copy of Ultimatte. The adjustment to virtually add spill control helps a lot in both keyers.
If you want to control spill contamiation on the actor during the shoot, and you can’t just move them away from the screen because the screen or room are too small, use a magenta backlight on a green set and “bastard amber” gel backlight for a blue screen set.
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