After Effects Masks
  1. Masking can be used when you tape a scene with a person on the left side of the scene, then tape the scene with the same person on the right side of the scene. Use a tripod, the only difference in the scene should be where the person is.
  2. Create a new composition.
  3. Import the footage.
  4. Drag your clips into the composition.
  5. Choose the pen tool in the upper left.
  6. Make sure the top layer is selected.
  7. Draw a rough outline around the person by making a rectangle. Click to set a corner. After setting the last corner click on the first corner to complete the mask. This will remove anything outside the rectangle and allow the bottom layer to show.

Adjustments:
  1. There can be minor changes in lighting that are noticeable. To fix it, click the triangle next to layer 1; then the triangle next to Mask; then the triangle next to Mask 1. Adjust Mask Feather to help blend the two clips together.
  2. Preview it.
  3. Save the project.
  4. Import your project into Premiere and add slate and countdown.
  5. Export with you usual settings.