Why is the result of the preview inconsistent with the photo after taking the photo when choose 720 * 480?

I have a question, why is the preview not the same as the shot when I choose 720*480 resolution；

I can obviously notice that the real photo height covers a larger area than the preview height，There is also a slight deformation。

Can someone tell me what's causing this?

> The aspect ratio of my Android camera is 16:9