1, open ae, right-click a blank space in the project and click "New Composition Group" in the pop-up menu.
2. A window will pop up after clicking. Set the size at this time. The width is required to be the same as the original video and the height is smaller than the original video.
3. Then import the video to be edited and drag it to the newly created composition group.
4. Adjust the position of the original video in the composite image. As you can see, the top of the original video has exceeded the canvas. At this point, you can cut off the top of the video by saving the exported video.