Game Development Reference
In-Depth Information
The Posterize Time Effect
The Posterize Time effect is as simple as it gets. The purpose
of the effect is to conform a video layer to a specifi c frame rate.
The only parameter for this effect is Frame Rate, which is the
absolute frame rate. This effect is useful for conforming video to
a fi lm frame rate (24 fps, which is also the default value for this
You can also achieve this same result with a little more effort
by precomposing a video layer, and in the Composition Settings
dialog box, change its frame rate in the Basic tab and then click
the Advanced tab and select the option with one of the lon-
gest names of all time: Preserve Frame Rate When Nested Or In
Render Queue. This will allow the contents of the precomp to
play at any frame rate, regardless of the frame rate of the parent
The Time Difference Effect
If you're familiar with the Difference blend mode, you know
that one of the uses of it is to be able to compare the pixels of
two layers to see where they differ, hence the name. The Time
Difference effect does the same thing, but it allows you to com-
pare frames from different places in time on the same layer. Now,
before you go skipping on ahead to Time Displacement, let me
tell you that this effect has some pretty useful features, especially
for color correction and visual effects workfl ows.
To start out, let's open the Time Difference.aep project from
the Chapter 19 folder, and apply the Time Difference effect to the
Chad with Hand Dot layer. This is just a video clip of me being a
goon in front of a green screen. So, when you fi rst apply this effect
and the screen goes gray, my sense of embarrassment subsides.
The reason the screen goes gray is because blending things in the
Difference blend mode is meant to compare things. When two iden-
tical objects are compared, the result is a solid color. With Difference
(the layer blend mode), identical layers become black when stacked
on top of one another. With the Time Difference effect, identical
frames become gray. And by default, the Time Difference effect
compares the current frame with the current frame.
Before we go any farther, let's actually adjust this effect so that
we can see something more than just gray here. Change the Time
Offset (sec) value to 0.2. You will then visually see where these
frames are different, because the difference (the nonidentical pix-
els) will not be gray (Fig. 19.6).
As has been our tendency throughout this topic, let's look at the
properties in this effect from the top down. The fi rst parameter is
Target. This drop down controls which layer is being compared
Making Time
Difference Behave
If you want
to make Time
Difference behave
like the Difference blend
mode, select the Absolute
Difference option, which
will change the gray
caused by identical pixels
to black.
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