TIme to Pull a Key?
by gedits
on
Mar 23, 2007 at 3:11:24 pm
My final product is going to be 1920X1080 24p 8-bit uncompressed. I'm filming all my green screen shots in DVCPRO HD 1080 24pA (1280X1080), with the advanced pull-down to 23.98p on import. Would it be better for me to pull my key in the DVCPRO HD codec, edit in DVCPRO HD, and then convert the final file to uncompressed? Or should I convert the footage right after import to uncompressed and pull a key uncompressed? Any idea which would yield a cleaner key? I'll be pulling the key in After Effects using keylight. Going to After Effects also brings up the next issue, YUV to RGB. When should I convert this? Thanks for any help in advance.
gedits
HVX200, Mac G5 4x2.5 Ghz. 4gig RAM, Final Cut Pro HD, After Effects 7 Pro, fingers crossed
Re: TIme to Pull a Key? by Dave LaRonde on Mar 23, 2007 at 3:36:12 pm
[gedits]"Or should I convert the footage right after import to uncompressed and pull a key uncompressed?"
You're not going to gain anything by converting to a better codec once your footage has been captured... so forget that step.
If you're using a Final Cut Pro - After Effects - Final Cut Pro workflow -- and you don't have the benefit of Automatic Duck -- just export your greenscreen footage from FCP to AE by reference (that is, NOT self-contained). If you have the Duck, good for you: you know the drill.
A non-self-contained clip points to (or refers to) the original footage, which is as good as it's going to get. Let AE automatically handle the YUV-RGB stuff, which it does nicely.
And don't forget: 24p with the pulldown removed, 23.98 and 23.976 (the frame rate that shows up in AE) are all the same frame rate, so relax.
Happy keying... hope everything's nicely lit, with minimal spill.
Re: TIme to Pull a Key? by gedits on Mar 23, 2007 at 3:55:10 pm
Thanks. So, I should pretty much just import my footage, place it in a DVCPRO HD/RGB sequence, render it, and export it as a not self contained reference movie? Will After Effects recognize the YUV to RGB change in the reference movie? I didn't know about this Automatic Duck software, it appears to make things a lot easier. Thanks again.
"I look forward to the day I'm keying with a 2/3 chip camera"
Re: TIme to Pull a Key? by Dave LaRonde on Mar 23, 2007 at 4:32:27 pm
[gedits]"I should pretty much just import my footage, place it in a DVCPRO HD/RGB sequence, render it, and export it as a not self contained reference movie?"
No, don't render! Don't put your footage into anything OTHER than an FCP sequence that matches the codec in which you're capturing.
If you capture as DVCPRO HD/RGB, then use a DVCPRO HD/RGB FCP sequence. If you capture as DVCPRO HD, then use a DVCPRO HD sequence.
The point is that you positively DO NOT want to render the clip(s) in question. That's the whole point of exporting by reference: you want the reference clip to point to the ORIGINAL MEDIA, and not some FCP render file.
Re: TIme to Pull a Key? by gedits on Mar 23, 2007 at 5:23:21 pm
I see. Do you know if the DVCPRO HD codec is natively YUV or RGB? I'm guessing YUV, because if I pull the captured clip directly into AE I need to expand the 601 luminance to make the footage appear correct. If it is YUV, at which step do I make it RGB? Thanks again.
Re: TIme to Pull a Key? by Dave LaRonde on Mar 23, 2007 at 5:47:53 pm
Oh, don't mess with that RGB-YUV jazz. AE accepts YUV footage just fine... it just happens to do its work in RGB color space, that's all. I use YUV footage all the time in AE, just as it is.
What you DON'T want to do is to render the first part of one long shot out of AE, and expect it to look exactly like the second part of that shot still in FCP. It ain't gonna happen; the gamma levels will be off by just a little bit.
But: you cut from an AE-rendered shot to a different shot in FCP, you aren't even going to notice. Not unless you have eyes like a waveform monitor... that's a scary thought.
Re: TIme to Pull a Key? by gedits on Mar 23, 2007 at 6:13:56 pm
I have been starting to see zebra lines in highlights as I walk down the street. Next will be an iris control knob on my temple. That aside, the one time I ran into an RGB/YUV issue, was when I did some garbage matte compositing in FCP using some effected AE footage. I could see a color difference between the two matching backgrounds. I'll keep the compositing jobs in After Effects and try not to mess with the RGB/YUV to much. Thanks.
