FORUMS: list search recent posts

Chroma Key and Effects Questions

COW Forums : Apple Final Cut Pro Legacy

<< PREVIOUS   •   FAQ   •   VIEW ALL   •   PRINT   •   NEXT >>
andrew spano
Chroma Key and Effects Questions
on Jun 16, 2010 at 8:50:49 pm

Ok... a few questions in this one so I don't know who wants to tackle it.

First. I have a chroma key problem - my friend Jake has blond hair and its really hard to get a good key or even color correct it. I can key any image or person out perfectly but it seems that when it comes to blond hair it always ends up looking like crap. The YouTube Link provided below will show you what I mean (skip to 1:44). I also provided a picture of what my key settings look like... what else can I do to fix this problem? It is green around his head and his hair is always "blurry".

Second. In the same YouTube link, if you skip to 3:30 you will see a smoke effect put in place... when the camcorder is moving the effect shakes around with the video. How do I stop this problem? A motion tracker? How do I track an effect like that?

Hope you guys can help. Cheers.







http://i309.photobucket.com/albums/kk366/mrgrey26/Screenshot2010-06-13at947...



Return to posts index

Kevin Knutson
Re: Chroma Key and Effects Questions
on Jun 16, 2010 at 9:59:48 pm

Probably not the most helpful answer to you, but I never use FCP for keying. It just never seems to come out right. If you have access to After Effects, I suggest you play with keylight, which will have no problem with his hair, if used right.

Blonde hair is always facing spill problems, so try playing with FCP's spill suppressor - green. That should help bring some detail back.

As for the smoke, motion tracking would be best, but also since its a very quick clip (and lets face it, not exactly photo realistic) you could frame by frame adjust the placement of the smoke (kind of a manual motion track).


Return to posts index

Dave LaRonde
Re: Chroma Key and Effects Questions
on Jun 16, 2010 at 10:03:48 pm

Well, since you've simply overwhelmed us with information on all SORTS of topics like:
  • your computer
  • your OS
  • your version of FCP
  • the type of footage you're shooting
  • the application/plugin you use for keying
  • how you light for keying

The best comment I can make is this: FCP doesn't like you any more. What did you do to make it angry?

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index


andrew spano
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 2:48:14 am

CPU: MacBook Pro 2.4 GHz Intel Core 2 Duo with 4GB 1067 DDR3
OS: Snow Leopard OSX 10.6.3
FC: Final Cut Pro 7
Footage: 60i MXP
Application: Chroma Keyer in FC
Lighting: 2 umbrella lamps


Return to posts index

Dave LaRonde
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 4:58:28 pm

[andrew spano]
"Footage: 60i MXP
Application: Chroma Keyer in FC "


Ugh. HDV plus the FCP keyer. No wonder you're having problems.

HDV may be hi-def, but to record the picture, they take shortcuts. for example, the picture is only 1440 pixels across, not 1920. How do they do it? They wake the pixels wide, not square.

Far worse is HDV's stinkin' lousy color resolution: for every pixel of B&W information, there's only ONE pixel of color information. It's enough to trick the human eye, but not computers. When you're chroma keying, what do you need? Good color detail. But what don't you have? Good color detail.

As soon as the image is recorded, the damage has been done. You can't improve the picture. You can only work around it keep the picture from degrading any further by converting it to ProRes 422 before you begin editing.

Then there's the built-in FCP chroma keyer, which is NOT Apple's most brilliant piece of software. You should use the chroma keyer in Motion, which is much better. It might be able to help with the hair, but with that automatically-lousy HDV footage, it's going to be a challenge.

Don't believe the old wives' tales -- and old editors' tales -- about deinterlacing your footage. It DOES NOT help you get a better chroma key. In most cases, deinterlaceing actually makes things worse.

As far as lighting goes, 2 umbrellas sound like enough... to light the chroma key background. It's always best to light background and subject separately. You'll want to think VERY seriously about doing that.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

andrew spano
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 5:06:15 pm

is there a prores 422 converter you could recommend?

i have a canon hf s10 - would recording with different frame rate or mode help?


Return to posts index


andrew spano
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 5:06:42 pm

it uses flash memory not tape


Return to posts index

Dave LaRonde
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 5:20:39 pm

[andrew spano] "it uses flash memory not tape"

Doesn't matter. HDV is still HDV, no matter what media it's recorded on.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

jochem smit
Re: Chroma Key and Effects Questions
on Jun 18, 2010 at 4:41:21 pm

Hi Dave,

Your answers and knowledge is great, thanks.

I have just keyed out a blue screen in AE. I want to go back to final cut now and create the background in the transparent space i've created. I did my render export by using millions of colors+, RGB+ALHPA, animation, quicktime, prores high quality. In Final cut i tried a lot with the composite but i cant get a neat composition. Either the background is invisble or it becomes mixed up with the keyed image. You have any clue what i do wrong and how to solve it?


Grtz... Jochem Smit (Netherlands)


Return to posts index


Dave LaRonde
Re: Chroma Key and Effects Questions
on Jun 18, 2010 at 6:16:47 pm

[jochem smit] "I want to go back to final cut now and create the background in the transparent space i've created... In Final cut i tried a lot with the composite but i cant get a neat composition."

That's the problem with simply pulling a key: if there are any areas of semi-transparency you didn't notice, you have to go back and do it again. That's one reason why I always recommend doing the ENTIRE shot, foreground and background, in After Effects. Then you can easily see any problem areas, and you can color correct so the foreground better matches the background. Furthermore, you don't have to render a movie with an alpha channel -- you can render in ProRes 422 or the edit codec you use in FCP.

Once you get used to the idea of doing the whole shot in AE, you'll probably want to add some extra touches like adding light wrap and creating fake shadows.







[jochem smit] "I did my render export by using millions of colors+, RGB+ALHPA, animation, quicktime, prores high quality."

Did you Render using the AE Render Queue, or did you simply Export the composition? In AE, the two terms have different meanings.

Animation and prores are two different codecs used in quicktime movies... so I don't know which one you used! Animation DOES support alpha channels, but ProRes does NOT. Among the current ProRes family of codecs, only ProRes 4444 supports alpha channels.

When making alpha channel quicktimes, there is one more consideration: the TYPE of alpha channel you should make. There are two, Straight and Premultiplied. You need to make the one that works best for the application that will use your AE work. For FCP, you probably need a Straight alpha channel. But you could render both types in two different files and see which one works best.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

jochem smit
Re: Chroma Key and Effects Questions
on Jun 18, 2010 at 9:35:55 pm

Hi Dave,

Thanks a lot.

I only work with the render queue, no exports..

I indeed did use apple prores before and didnt get the alpha transparency i desperately needed in FCP.
Afterwards I used animation (millions of colors+ & RGB+ALPHA) and it worked so thats cool!

Since I work ok a macbookpro laptop it takes me 25 minutes to render a shot of one minute (in the queue) with those settings. Apple Prores 4444 seems to be even heavier. Which codec do you advice me for time and alpha sake?

Do you for example think straight can reduce the render-time compared to premuliplied? Thusfar I only did premultiplied and it resulted in the result i need....

Finally... my reason not to edit my whole sequences (its no shots, its whole timelines) of fore and background in AE is the fact that I dont feel secure to the interface of the sequence, there is no sound, there is slowmotion, i cant easily scroll through the timeline etc... I'm even not sure if AE is honest to my resolutions and image ratio's... This all caused by the fact that I'm new to AE. I want to be back in FCP with my Alpha channel asap:)...

Thanks for time and effort,

Jochem






Return to posts index

Dave LaRonde
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 5:19:04 pm

[andrew spano] "is there a prores 422 converter you could recommend? "

Compressor.

Also MPEG Streamclip -- Free download. Google it.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

andrew spano
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 5:34:56 pm

I appreciate your advice. Thank you.


Return to posts index

andrew spano
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 6:16:49 pm

actually... one more question just so I get this straight - I import my footage from camcorder to final cut (thats the only way I know how to import) then I find the folder that the clip is in and put it in compressor and use that to change it?


Return to posts index

Dave LaRonde
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 6:46:57 pm

Yup.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

andrew spano
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 9:38:51 pm

I brought in some footage from my camcorder into finalcut then saved it on my desktop... when i click info it says CODEC: Apple ProRes 422, Linear PCM, Timecode. If its already in prores then why do I have to use compressor?


Return to posts index

Dave LaRonde
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 10:25:34 pm

You don't. That's excellent. Now all you need to do try out that chroma keyer in Motion.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

andrew spano
Re: Chroma Key and Effects Questions
on Jun 17, 2010 at 11:20:24 pm

I can't figure out how to use the Motion Keyer properly (sorry I'm obviously new at this) so I'm looking up tutorials and installing Boris Continuum Effects in the meantime. I heard that has a great keyer.


Return to posts index

Kevin Knutson
Re: Chroma Key and Effects Questions
on Jun 18, 2010 at 4:51:17 pm

There is a learning curve for any keyer. A lot of people think its just a matter of putting people in front of a some green paper or fabric and clicking a button. But the word of the day for keying is "finess".

Brush up on several tutorials, and dont be afraid to start over with the key if its not going right. Sometimes a pixel sampled just wont yield good results, whereas the pixel group next to it will.

Forgive my assumption, but this seems like a personal project, and not really for a client. So take a chance to look at this as an enormous learning opportunity. Learn what worked and what didnt. And for god's sake, DONT use FCP for your keyer anymore.


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2018 CreativeCOW.net All Rights Reserved
[TOP]