Photos app stuck on 'Preparing Video' during editing or cropping on iPad

It would help if you could tell us more about what's happening:

1. Are you editing in the iPad Photos app?
2. What sort of video? Is this one that you took with your iPad, or did it come from another source?
3. What is the size of this video in MB?
4. When you say, "it’s showing preparing video," do you mean that you're getting an error message? What does it say, exactly?
5. Can you edit pictures?
6. Can you edit other videos, or is it just this one?
7. Are you using iCloud Photos to synchronize your devices?
8. Do you have “Optimize Storage” checked in Settings
9. Do you have more than 10% free storage on your iPad?
10. Do you have more than 10% free storage on your iCloud account?
11. Has this problem always existed, or did it just start? Can you think of anything that changed that might affect your device?

In the mean time, try a forced restart of the iPad:

Force Re-start iPad

This is different from a simple Power Off. For me, the logo appears way after the Power Off notice.

Let us know so we can help…