Chroma Keying Help

Mutley · #1 (**permalink**) 06-21-2006, 03:24 PM

Hi there,

First post. I'm doing a project at College, filming and editing a short movie and really need help with Chroma Keying.

I have 2 layers, the actual footage, then the footage in the blue room.

If I have a man stood in the middle of the screen in my blue room. Then in my main footage I'm panning following a car. The man stood in the room will follow in the middle of the screen with the pan. He "floats".

How do I unlock, reposition each frame, to sync the 2 layers, so when my camera pans, the man stood still goes to the edge, then off my screen?

I hope you understand!

I am using Adobe Premiere Pro 2.

- Nick.

Alan Mills · #2 (**permalink**) 06-22-2006, 11:24 AM

Just keyframe the position of the clip so that it asppears to 'slide' off the side of the screen in time to the camera pan of the other clip.

Or... if you have After effects you can get AE to do it all for you.

Mutley · #3 (**permalink**) 06-22-2006, 12:55 PM

Thanks,

I just need more information on how to do it. I havn't a clue about keyframes, looked in help but didn't find anything useful.

Not sure what AE is either?

Alan Mills · #4 (**permalink**) 06-23-2006, 11:45 AM

Originally Posted by Mutley

Thanks,

I just need more information on how to do it. I havn't a clue about keyframes, looked in help but didn't find anything useful.

Keyframing (whether it be for position, size and/or plugin attributes) is such a fundamental concept in video editing that I respectfully suggest you spend some 'real time' with your user manual and read up on it. I could explain the concepts but it's an essay that is rather too long for me to do justice to in a forum post.

Originally Posted by Mutley

Not sure what AE is either?

AE = Adobe After Effects. Might be new version 7 features but it contains some nice 'tracking' features that would do this for you pretty much automagically.

Mutley · #5 (**permalink**) 06-23-2006, 01:56 PM

Originally Posted by Alan Mills

Keyframing (whether it be for position, size and/or plugin attributes) is such a fundamental concept in video editing that I respectfully suggest you spend some 'real time' with your user manual and read up on it. I could explain the concepts but it's an essay that is rather too long for me to do justice to in a forum post.

AE = Adobe After Effects. Might be new version 7 features but it contains some nice 'tracking' features that would do this for you pretty much automagically.

I will try AE first, if it doesn't do what I need, I'll dig the manual out and try keyframing.

Thanks Alan.

Alan Mills · #6 (**permalink**) 06-24-2006, 08:27 AM

Originally Posted by Mutley

I will try AE first, if it doesn't do what I need, I'll dig the manual out and try keyframing.

Thanks Alan.

Er, just so you know. The AE option I mentioned is very much the 'Super Advanced' option here. You can do it but for what you want it's a bit over-kill. Key framing the positiohn of your clip so it 'slides' off the side of the page as you pan is a one minute job (once you know how to keyframe).

You'll sit there all week getting it sorted in AE unless you already know how to do it - which I guess you don't or you wouldn't be asking would you?

=ChrisB= · #7 (**permalink**) 06-25-2006, 12:03 AM

Originally Posted by Alan Mills

Er, just so you know. The AE option I mentioned is very much the 'Super Advanced' option here. You can do it but for what you want it's a bit over-kill. Key framing the positiohn of your clip so it 'slides' off the side of the page as you pan is a one minute job (once you know how to keyframe).

You'll sit there all week getting it sorted in AE unless you already know how to do it - which I guess you don't or you wouldn't be asking would you?

Yea its WAAAAAY advanced. I'd just learn keyframing. Alot easier and its more useful!

Mutley · #8 (**permalink**) 06-25-2006, 06:15 PM

Right, I've found out how to do it and got the hand of it (keyframing). However I have one problem.

I'm finding it really hard to keep it smooth. The blue screen layer, is really hard to keep in the exact same spot every frame, I am doing this every single frame for the whole clip and it is really time consuming, the result of a smooth "looks real" feel is seeming impossible to achieve. Any tips or tricks at all on doing this?

Tony A · #9 (**permalink**) 06-25-2006, 10:38 PM

Others here will probably explain it better than me. Sounds as if you’re making hard work of it. No need to keyframe every frame – you only need to set a start position and an end position. Premiere will interpolate all the intermediate frames ‘smoothly’.

Alan Mills · #10 (**permalink**) 06-26-2006, 04:03 PM

Originally Posted by Mutley

Right, I've found out how to do it and got the hand of it (keyframing). However I have one problem.

I'm finding it really hard to keep it smooth. The blue screen layer, is really hard to keep in the exact same spot every frame, I am doing this every single frame for the whole clip and it is really time consuming, the result of a smooth "looks real" feel is seeming impossible to achieve. Any tips or tricks at all on doing this?

The chances are, that if you cannot have your actor peel off the screen smoothly along with the background then you have an unsteady panning shot behind it.

From how I picture the shot you are making I would imagine you need only a start and end keyframe. Let Ppro fill in all the missing frames. I do not think it needs to be pixel perfect on every frame or your perspectiuve will look funny anyway.