Multicam /Transcode Green Screen Question

[Andy Neil]

[Michael Hadley] “I ask this because it turns out once you create a non-optimized multi cam clip, it turns out you can’t subsequently transcode it up to Pro Res. “

What makes you say this? I’m able to select my non-optimized multiclip and ask FCPX to transcode media and it gives me the option of optimized media.

If yours doesn’t, then perhaps FCPX considers your base media to be optimized already.

As for exporting proxy, just make sure you have Use Optimized Media turned on in the preferences and you should have nothing to worry about.

Andy

https://www.timesavertutorials.com

[Michael Hadley]

Hmm. That’s possible. The original source is XDCAM 422 100mpbs, so it’s fairly robust. BUT, I thought FCPX only considers ProRes to be optimized.

When I click on the transcode options in the multi cam clip, neither proxy nor optimized is available. Proxy I understand because I had proxies made of the all original source footage .

The reason for my questions is that this is a green screen job and I’m having some trouble pulling a key (even when I go back to source footage). I’m wondering if Pro Res would do a better job handling the problem areas (a woman’s hair with green spill). My test so far have proven inconclusive. Have tried the keyed in X, PHYX and CVH. Results have not been that great.

Thanks!

[Andy Neil]

FCPX considers any codec that it can interact with natively as “optimized.” This includes XDCam if I’m not mistaken.

I’ve never been all that impressed with XDCam 422HD as a codec for keying, mostly because I don’t think it’s an I-frame codec, and those long GOP codecs aren’t very good at pulling keys when there’s difficulty. If you recorded MPEG2-IMX, then that’s an I-frame codec and is much better for projects like keying (not sure what camera you were using).

So, switching to ProRes will put you in an I-frame codec, but the color sub-sampling will be the same (4:2:2), so I’m not sure how much better things would work (if at all).

Andy

https://www.timesavertutorials.com

[Simon Ubsdell]

[Michael Hadley] “the problem areas (a woman’s hair with green spill).”

A quick suggestion about keying “problem areas” (and forgive me if you already know this) is to treat them as separate areas and not try and find a global key that works across the whole frame.

So make a soft edge mask to include the majority of the key and then invert the mask to use on a separate layer for the problem section – it’s almost always hair but it could be anything, like colours that are a bit too close to the background.

With hair you want a much higher degree of transparency on the edge than you want or need elsewhere (and probably a different approach to spill suppression as well) and this is really the only way to achieve it properly.

Also if you are trying the key with the FCPX keyer do have a look at the Edge tool which helps with quite a few issues. The lightwrap works very well also and can make a big difference and again is going to be useful for hair detail in a lot of cases.

The other thing which I’m sure you know is to use a garbage matte to eliminate as much of the background as possible so you’re not trying to key unnecessary areas.

Simon Ubsdell
http://www.tokyo-uk.com

[Michael Hadley]

Thanks Simon for all the useful tips.

I will probably end up doing just what you suggest. The problem is a fair amount of green spill into the outer hair rim, which is kind of frizzy. Using light wrap, edge control, softening, etc. makes for a strange looking halo (or is that hair-o) that is just not that great.

I’ve never tried the plug in Keylight-do you think I might get better results than X, PHYX or CVH?

Thanks again.

[Michael Hadley]

Thanks for the explanation of when/if X will optimize.

The shoot was done with Sony EX3s going to Nanoflashes, so the resulting files are 4:2:2 XDCAM LG @ 100mbps.

I did a test converting on a sample to Pro Res and keying with it. I couldn’t really see much of a difference. But–I’m thinking I might export the completed video (with no key) as Pro Res, then bringing it back in to do the keying with Pro Res in the hopes it might go a bit easier.

[Simon Ubsdell]

[Michael Hadley] “I’ve never tried the plug in Keylight-do you think I might get better results than X, PHYX or CVH?”

Unfortunately the short answer is that it’s not down to finding the perfect one-stop keyer, whichever one you go for.

Keylight is a top of the range keyer (but needs some experience and knowlededge in order to get really great results) but at the end of the day no off-the-shelf keyer is going to do a perfect job with difficult material straight out of the box.

To be honest, despite a lot of the claims you hear for one keyer or another, working in a nodal compositor is really the only proper answer to getting a first class key, anything else is a compromise of one sort or another. Nodal compositing gives you far more power and accuracy than anything you can achieve in a layer based environment, because a really good key is about a whole chain of different processes rather than just a simple click of a button. If you are interested in this route, I can strongly recommend investigating Conduit – which now has a version for FCPX – and will get you outstanding results, but there is a considerable learning curve.

But one way or another, it’s all really down to taking pains with the individual shot. As I suggested, breaking the shot down into different areas and recombining them is definitely the best way to go in almost every case. Remember that for hair it’s the transparency of the edges that you’re looking for. Don’t worry too much about the bleed-through of unwanted colour from the backing because that’s what the spill suppression is for. The main thing is not to crunch the key too hard for hair – you want grey values, not black and white, hence the need to treat it separately from the rest of the key.

I’d say that with a lot of care you could get reasonable results from the FCPX keyer in most instances, certainly as good as any other instant-fix keyer out there, but only if you adopt the patchwork route I’ve described. Do try to get the absolute best black and white matte before you start playing with any of the other controls though.

Simon Ubsdell
http://www.tokyo-uk.com

[Simon Ubsdell]

[Michael Hadley] “But–I’m thinking I might export the completed video (with no key) as Pro Res, then bringing it back in to do the keying with Pro Res in the hopes it might go a bit easier.”

I’d say that this would be a sensible route – Pro Res should give you better results.

Simon Ubsdell
http://www.tokyo-uk.com

[Michael Hadley]

Thanks, Simon. Sound advice from a pro. Much appreciated.

[Michael Hadley]

Just to close the loop on this.

Finally achieved a very good key. And was actually able to do it in FCPX. The key was to turn down the automatic sample strength to about 7%, take my own samples, and add 4 edge pins.

A slight shift on the color bias, a bit of softening on the matte and a touch of light wrap, and it all looks very good.

But the key (no pun intended) was turning off X’s automatic sampling and using the edge pins. I’m sure PHYXX and CVH are wonderful tools, once mastered, but I was able to get a very good result from X.

Thanks for everyone’s great advice.