Compositing in Final Cut Pro X Ripple - Lesson 1: Keying a Green Screen Subject

Question 1

Our first task is to key out the green screen behind the actor. To get started, let’s put a background in place so there will be something to see when we key the shot.
Adding a Background
In the Compositing event, select the Background Video _______ __________ and skim through the video clip in the Event Browser. This Tropical Beach clip may not be what we want for the final spot, but it will work for now.

Answer 1

keyword collection

Question 2

In order to match its duration to the duration of the clip in the Timeline, click in the Timeline to make it active and then press _ to select the clip under the playhead. Then select the Tropical Beach clip in the Browser and press Q to perform a connect edit. The tropical beach clip is edited into the timeline matching the duration of the green screen clip.

Answer 2

X

Question 3

In order to match its duration to the duration of the clip in the Timeline, click in the Timeline to make it active and then press X to select the clip under the playhead. Then select the Tropical Beach clip in the Browser and press _ to perform a connect edit. The tropical beach clip is edited into the timeline matching the duration of the green screen clip.

Answer 3

Q

Question 4

The tropical beach clip is edited into the timeline matching the duration of the green screen clip, but it’s above and we want it below. Hold down the _____ key to keep the clip from moving left or right, and drag it below the green screen clip. Click above the clips to deselect them all.

Answer 4

shift

Question 5

Keying the Shot
Ok, now for the key. Let’s choose a good representative frame. Move the playhead to the point where the actor extends his arm fully - at a about 2:00. Then press the _ key to turn off skimming so we can focus on this frame.

Answer 5

S

Question 6

Keying the Shot
Ok, now for the key. Let’s choose a good representative frame. Move the playhead to the point where the actor extends his arm fully - at a about 2:00. Then press the S key to turn off skimming so we can focus on this frame. In the toolbar, click the button for the Effects browser if it isn’t open already, and select the ______ category.

Answer 6

Keying

Question 7

Drag the _____ effect onto the green screen clip. Press Shift-Z to fit the clips back to the timeline. The clip is immediately keyed, and looks pretty darn good right there. Scrub the playhead through the clip, then return to 2:00.

Answer 7

Keyer

Question 8

There are a few things we need to fix. First, there’s a huge shiny board on the right side of the screen - it’s there to bounce some light on the actor, but we don’t want to see it in the shot. A ____ will take care of that.

Answer 8

mask

Question 9

Notice what looks like a reflection of the water under his extended arm. That doesn’t look quite right. If necessary, click the Inspector button in the toolbar to open the Inspector.
In the Keyer controls, click the middle View icon - the one with the white silhouette on the black background. This button shows the _____ created by the key.

Answer 9

matte

Question 10

A good key will be all _____ in the areas you want to see, and all _____ in the transparent areas. The matte makes it clear that this key has a few problems - the area underneath the actor’s arm is actually partially transparent, as is part of the logo on his shirt.

Answer 10

white, black
(also think about: the video with the greenscreen is on “top” in the timeline and the background image is on the “bottom”)

Question 11

Creating a Manual Key
By default, the keyer works automatically. Often this is all you need, but in situations like this, you can PULL THE KEY manually. To do so, the first step is to change the Strength parameter. Think of the Strength parameter as the amount of _________ keying being used - at 100%, it’s a fully _________(same as other blank) key.

Answer 11

automatic

Question 12

Creating a Manual Key
By default, the keyer works automatically. Often this is all you need, but in situations like this, you can pull the key manually. To do so, the first step is to change the ________ _________. Think of the Strength parameter as the amount of automatic keying being used - at 100%, it’s a fully automatic key.

Answer 12

Strength parameter

Question 13

Creating a Manual Key
By default, the keyer works automatically. Often this is all you need, but in situations like this, you can ____ ___ ___ manually. To do so, the first step is to change the Strength parameter. Think of the Strength parameter as the amount of automatic keying being used - at 100%, it’s a fully automatic key.

Answer 13

pull the key

Question 14

Creating a Manual Key 2
Switch the View back to the first image, which is the composited final result, and then drag the slider down to 0%. The green background returns. Now, to key the shot manually, you need to provide the key effect with some information. First, we’ll tell it the color of the background to remove. In the ______ ___ section, click the Sample Color image.

Answer 14

REFINE KEY

Question 15

Creating a Manual Key 3
Switch the View back to the first image, which is the composited final result, and then drag the slider down to 0%. The green background returns. Now, to key the shot manually, you need to provide the key effect with some information. First, we’ll tell it the color of the background to remove. In the Refine Key section, click the ______ _____ image.

Answer 15

SAMPLE COLOR

Question 16

Creating a Manual Key 4
In the Refine Key section, click the Sample Color image.
We’ll use this tool to draw a rectangle on the green background. But where should we place it? Often a green screen background is unevenly lit, and you want to sample a color _____ to the object you want to keep, and often close to a more difficult area to key, like hair. This green screen is lit very evenly, so it doesn’t matter as much. But just to be careful, draw a rectangle close to the actor’s head.
The green background disappears immediately.

Answer 16

close

Question 17

Creating a Manual Key 5
But just to be careful, draw a rectangle close to the actor’s head. The green background disappears immediately. Notice that it doesn’t seem to matter how big the rectangle is - this is because the background is lit so evenly, there’s aren’t other ______ of green to include in the rectangle. If there were, you could make the rectangle large enough to include them, or even draw several rectangles on this frame. Notice also that the area under his arm no longer seems to have a reflection of the water.

Answer 17

shades

Question 18

Notice also that the area under his arm no longer seems to have a reflection of the water. In fact, the only thing that looks a little bad in this view is his extended hand and the dynapep product have a hard outline around them. Let’s switch to the _____ view.

Answer 18

Matte

Question 19

The matte is a nice solid white, and the background is a solid black, just like we want. But ideally the very edges should be shades of ____, for a more gentle transition.

Answer 19

grey

Question 20

The matte is a nice solid white, and the background is a solid black, just like we want. But ideally the very edges should be shades of grey, for a more gentle transition. In the Inspector, click the _____ image. Now, draw a line from outside the actor’s hand to inside his hand.

Answer 20

Edges

Question 21

But ideally the very edges should be shades of grey, for a more gentle transition. In the Inspector, click the Edges image. Now, draw a line from outside the actor’s hand to inside his hand.
We get a softer edge, but parts of his arm, his face, and the logo on his shirt become ___________.

Answer 21

transparent

Question 22

But ideally the very edges should be shades of grey, for a more gentle transition. In the Inspector, click the Edges image. Now, draw a line from outside the actor’s hand to inside his hand. We get a softer edge, but parts of his arm, his face, and the logo on his shirt become transparent. Drag the end points and the center line between the end points of the edges control to adjust the sample until most of his arm and face are white - don’t try to make the logo (on his shirt) fully white because you can’t do so without ending up with very ____ edges.

Answer 22

hard