Original subtitles

In this clip we are going to look at refining the edges and

the alpha channel of our green screen image.

So this image is from our previous clip and it is the basic composite

of our green screen image over top of a background.

The main issue that we had with the alpha was over here in the glass reflection.

So it was making our image transparent through to the background,

which didn't quite make sense.

So let's take a look at our script and figure out how to refine that.

So we have an optimized Keylight from our previous clip

and we're going to fix this hole.

Now if I take a look at the Keylight and change it to final results,

we can see that it is definitely visible throughout the shot.

And sometimes it's wider than others.

Look at that, somewhere in between.

It definitely goes wider.

So we're going to add a Roto shape to try to fill that in.

So because it is on the inside or core of the image, a Roto shape should work.

So let's go back to my original image before it was keyed.

And back to frame one.

And I'm going to add a Roto shape.

So O for Roto shape and I like to use a Roto shape instead of a

RotoPaint tool because it represents Roto.

So RotoPaint to me symbolizes that there might be a clone brush or

some kind of paint brush in general being used,

versus this is just a pure Roto Bezier shape.

So I'm going to select the Bezier.

And I'm going to draw a garbage matte around the trouble area.

So I don't want to make it too wide,

if I make it too wide on the left hand side there,

then I might run into issues with the elbow,

because I know his elbow gets very close to this glass.

So let's just go every tenth frame for now and see if

that works overall to start with.

So far, so good.

Oh, it gets very close there, so let's pull it in a little bit.

And looks like it holds up for the most part in the rest of the shots,

but if I go to frame 65, it suddenly gets wider.

So I'm going to pull that down just a bit and add a

second Bezier shape to this wide section.

Now remember that this is a locked camera,

so that means that the camera doesn't move.

So the glass itself doesn't move,

but the reflection is changing because the character is changing.

So let's just toggle through, make sure that that holds up.

At least to begin with for the garbage mattes.

Oh, it gets a little bit close, frame 70, we'll just pull that in a little bit.

And that should work.

Now how do I apply this to my Keylight tool?

Well, there's two inputs that we haven't used yet.

The first one is InM and the second one is OutM.

InM represents the core matte, hard matte or inner matte.

So I'm going to hook it up and take a look at my Keylight.

Now you're going to notice that it hasn't done anything for us yet.

So in fact it still has a hole inside of my core.

So I have to change something inside of the Keylight

so that it recognizes this input.

So I go into the Keylight property then scroll down to

the bottom it says InM Component, OutM Component.

They're both currently set to none.

So it thinks that it doesn't have to recognize it, it can just ignore it.

So if I tell it alpha, it will automatically fill in that hole.

So now let's just toggle through a few frames like we did before,

just double check.

No major holes there, so let's do a preview.

So I'm going to add what's called a region of interest and

that allows me to just preview what's inside of this box

so it's a little bit faster,

so I don't have to preview the whole frame and now I can just

isolate the region that I want to preview.

So let's just preview that very quickly.

Make sure there's no holes.

It's looking pretty good.

So I think we have resolved the issue.

Let's just stop that and go back to full color.

And go back to the full composite.

So view composite.

And it looks like it's fixed our hole.

Now, it is doing something kind of funny,

it's giving us a gray reflection now in the glass.

So it is possible that we might want to go in there in our

next clip and just color correct that.

But for the most part,

we have now refined all of the holes that were previously

in our alpha and we are ready for the last few steps and

that is adding a light wrap,

reintroducing the noise and a couple of other different elements that will help

integrate this image into the background plate successfully.