A standard task for video editing is to trim footage to a desired duration before adding it to a program. In After Effects, you can trim footage before you add it to a composition, and the workflow is similar to how it works in a video editing application such as Adobe Premiere Pro CC.
ACA Objective 4.3
The basic trimming workflow is to open a footage item in its own window, and then set an In point and Out point to it. Those mark the new starting and ending frames for the footage. The trimmed footage is then ready to be added to a composition.
To trim footage as demonstrated in Video 3.7:
In the Project panel, double-click the colorFlow.mp4 footage item.
It opens in the Footage panel. While this looks a lot like the Composition panel, it’s important to notice that you’re looking only at a single footage item and not a composition.
Change the current time to when you would like the footage to begin playing.
Click the Set In Point To Current Time button.
Change the current time to when you would like the footage to stop playing.
Click the Set Out Point To Current Time button (Figure 3.7).
Figure 3.7 Media trimmed in the Footage panel
When this footage is added to a composition, it will include only the frames between the In point and Out point that you set.
To adjust the In point or Out point:
In the Timeline panel, drag the left edge or right edge, respectively, of a layer. In this example, you’re trimming a layer in the Footage panel, but you may remember from Chapter 2 that the same technique works for adjusting the In point and Out point in the Timeline panel for a layer in a composition.