I am having the same problem in Final Cut Express 4.
I know the concept of “scale and crop” but when I am scaling and cropping, I am still left with black bars on each side of the video. It seems that I am able to crop/scale the white background and the video but not the canvas. Here is a screenshot of what I am working with…
https://www.brokersalliance.com/paperwork/crop.gif
Even after I export the video, I am still left with “unused space.”
I want the white background to fill the total space yet when I resize the video/white background, I am left with black excess.