Final Cut Pro X has many strengths, and the new Keyer is one of them. Assuming you've shot your footage cleanly, you'll get great results as soon as you apply it. And yes, you can tweak the results to improve it even further. But what if near enough isn't good enough? Here we'll explore two options to get an even better keyer with FCP X 10.0.3.
In this tutorial, we'll be using sample footage from the nice people at http://www.hollywoodcamerawork.us/greenscreenplates.html, so go ahead and download their Hair Detail clip. The clip is provided as an image sequence, so you'll need to use QuickTime Player 7 or Motion to turn them into a movie. The process with Motion:
Now you've got a movie that will work at full speed, at very high quality.
Import this movie into FCP X.
We've looked at the basic functions of the Keyer effect before [http://www.macprovideo.com/hub/final-cut/how-to-green-or-blue-screen-in-fcp-x]. Here, I've connected the clip to be keyed above a 'Vivid' generator set to blue.
The Keyed clip above a Vivid generator
FCP X 10.0.2's Keyer effect does pretty well, but without additional controls, it can be tricky to tweak the results with just the built-in controls. For example, stray hairs around the foreground talent show visibly lighter edges against dark blue or black. No matter how you pull the Edges sliders, they just won't go away. The options you need to tweak didn't exist until 10.0.3, unless you used Motion.
Just the Keyer effect applied
The Matte Tools in the new FCP X 10.0.3 Keyer are a good place to start. You can tweak the edges in new ways, by shrinking, feathering or eroding the edges. However, the easiest way to improve this key is to finesse the edges using the Bias slider.
The same clip with the Matte Magic effect added after the Keyer
We'll start the effect again, nearly from scratch:
Without changing any settings, on black '" the hardest background possible.
The Advanced section, where you can adjust fine details of the key's Chroma and Luma
Manual gives you access to the with the Luma controls below the Chroma, and to the inner color box in the Chroma area.
In this tiny box, dragging the inner curved edge slightly away from the center of the color wheel to make the key slightly less aggressive. This restores some fine hair, at the cost of a slightly noisier background.
The Fix Video option here softens the jaggy edges that can result from the reduced color space (likely 4:2:2 or 4:2:0) that most cameras produce. You can safely disable this if your video source is 4:4:4.
Spill Suppression is what we need to fix this problem, and specifically the Spill Contrast control.
The starting settings for Spill Suppression
Light Wrap is an attractive option. It lets light from the background bleed over the top of the foreground element to help sell the effect. However, you will need to incorporate a background element into your project for this option to work, and we'll leave this off for now.
Light wrap '" you'll need a background element to use this
To make sure that this result looks good against all backgrounds, we'll now perform a torture test:
If the key is good, it should work on all kinds of backgrounds '" and this one should.
Phew! There's a lot to take in. The bottom line: FCP X's Keyer is good without tweaks, but challenging keying jobs can be dealt with too'"with or without Motion. Good luck!
The final result after tweaking in FCP X