Green Screen using P2 -> FCP workflow

[Jerry Hofmann]

First relax… it’s a piece of cake. I’d take a laptop to the set to check out your lighting for the key, i.e. import it, and see how it keys out the green over anything…) I just did this very thing in a class I’m teaching, and the DVCPROHD keys were perfect.

Jerry

[Mike Jackson]

I just finished up a show with a bunch of greenscreen footage from the HVX. Some of it keyed wonderfully, but one shot was an unbelievable pain in the ass.

Like DV, DVCProHD has a lower color space… so watch for bleed and buzzing on your brighter edges. We had a gold rim-light on our actors and the center of our screen was too bright, so the chroma got way too close. That caused no end of trouble for the key… Could’ve gotten away with it in HDCam, but in DVCProHD, not so much.

The HVX does an upres from a slightly smaller sensor, too, so you’ll get some softening in the image. I shot at 1080 which compounded my problems…

[Jerry Hofmann]

DVCPROHD resides in 4:2:2 color and DV resides in 4:2:0 for PAL or 4:1:1 for NTSC… so P2 does have a higher qualtiy color space than DV…

Jerry

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[Joe Murray]

You should be OK with the HVX, depending on what you have to do with the footage (eg. I would not try to shoot a feature film quality greenscreen shot with the HVX). The main issues keying DVCProHD have to do with edge artifacts due to the codec’s pixel shift technology to turn 960 x 720 pixels into 16:9 720 HD. This can usually be overcome with some decent matte tools downstream from the actual key effect. If I were you I’d try to avoid challenging key material such as wispy hair or objects that are small in frame, because the matte tools will affect these more than larger objects with clean edges.

The HVX has a pretty cool feature called a “marker,” which when turned on will act sort of like a spot meter, telling you the luminance value of whatever you point it at. If the DP uses the HVX a good bit he will know how to do this. I recently did a greenscreen shoot and was able to aim the camera at the greenscreen and slowly pan around the entire screen to make sure we had nice even lighting and a luminance value of 45%. The marker feature helped us nail the lighting, and I was able to do the final keys in FCP without having to step out to a compositing program.

The only other thing about that particular project that helped us was that we were finishing to SD, so the edge artifacts were much less noticeable than when projected in HD.

Joe Murray