Things You'll Need:
Adobe After Effects CS4
Create a new composition by clicking "Composition," then "New" from the main menu.
Enter "My Composition" as an example title in the Composition Name field.
Select the type of video you plan to edit by choosing from the Preset pull-down menu. For this example, select "NTSC DV" and enter "30 seconds" in the Duration field.
Import the video clips. Double click anywhere in the After Effects Project window, select the video files, and click the "Open" button.
Double click a video clip you wish to add to the composition.
Set the point where you want the video to begin by positioning the time marker at that point on the time line and clicking the "Set In" icon in the monitor window. Set the point where you want to end the video clip by moving the cursor to the end point on the time line and clicking the "Set Out" icon.
Place the video clip in the composition by clicking the "Overlay Edit" icon from the monitor
In the My Composition window, select the video clip layer added in the previous step and press "Shift" and "Ctrl" and "Alt" and "Right Arrow" to place the composition cursor at the end of the video clip.
Double click the next video clip you wish to add to the composition.
Repeat steps 6 through 9 until you have assembled all the clips you want in your final video file.
Add a 10-frame dissolve from black on the first video clip in the composition by pressing the "Home" key to position the Current Time Indicator at the beginning of the composition.
Press the "T" key to open the Opacity controls for the layer. Click the "100%" opacity value and enter "0."
Click the key frame icon that looks like a stop watch next to the Opacity control.
Press "Shift," then "Alt," then "J" to go to a specific time in the composition window.
Enter "10" in the Go to Time window. The Current Time Indicator will now be positioned at 10 frames into the composition.
Click the "0%" opacity value and enter "100." You now have a 10-frame fade-up from black to the first video clip.