Import the video to which you want to add the background picture, and then click "Free Zoom" in "Picture Style" to adjust the zoom value to a negative value, and you can see that the picture has been reduced. Of course, you can also adjust the values of X and Y, and move it up, down, left and right to move the video to the appropriate position. Then, the core step is to add a background image, which can be brought or customized. In this way, the effect of adding a background image to the horizontal video is realized.
Add a background image to a horizontal video.
I hope I can help you solve the problem ~