I've discover that after reinstall DJI GO (P4Pro) all my local videos cached disappear. Is it possible to recover iPad local videos from SD or there's other way to recover them? Thanks.

Previous video cache in the Editor will be lost after uninstalling and installing DJI Go APP. There is no official method can be provided to you at the moment. We are sorry for the inconvenience.

Do you have backed up your local videos via iTunes or iCloud? If so, you can recover them from the backup files. If you don't have any backup, you might need a secure ios data recovery program to help you restore you iPad local videos. Because iTunes can't retrieve  iOS data without using previous backup files. If you want to directly recover data from iOS, you are supposed to try something that is different from iTunes.

If you have a backup, you can recover the local videos from iTunes Backup. If not, you can recover from the iOS Device. Or maybe you should ask data recovery tools or recovery services for help. There are many tools can help you restore local videos from your iPad, such as Bitwar, Disk Drill, Wondershare, etc. Have a try. Hope they will help you.

It's really painful to lose or delete meaningful videos to record a wedding, baby's growth, happy party, touching moment, etc.
Don't be panic if this data loss happens on your iPad. You can give an iPad data recovery tool a try.
It will start to scan data from your iPhone at fast speed, preview to check desired data and filter needless files as you want.

See More: How to Recover Deleted Videos from iPad