Creating a Composition for Keying
Device Central created several compositions for you, but it can be difficult to see keying errors or subtle changes using compositions created by Device Central, which are at a lower resolution. Because you will also be preparing this project for viewing on larger screens, you'll create a separate composition for keying.
- Choose Composition > New Composition.
- In the Composition Settings dialog box, type Color Difference Key in the Composition Name box.
- Make sure the Preset pop-up menu is set to NTSC DV. This automatically sets the width, height, pixel aspect ratio, and frame rate for the composition.
- In the Duration field, type 1023 to specify 10 seconds and 23 frames, which matches the length of the MobileSportsIntro.mov footage item, and then click OK (see Figure 3).
After Effects opens the new composition in the Timeline and Composition panels.