answer:iPhone doesn’t have a conventional file system, so it’s not quite as simple as it would be with a real smartphone. There are special programs like Dr Fone (not free) and Ease US, but the fact that you didn’t already know that and are asking this question tells me that you probably would not be able to use those. It’s possible that the Geniuses at the Apple Bar may have some secret trick to get into their proprietary stuff and the willingness to help you out, but no guarantees. If you synced it with iTunes already though, all bets are off. In the meantime, don’t use the phone or it will assume that the storage are where the video was is blank and write over it. Set the phone to airplane mode. And do not sync it to iTunes! Unless…. If you synced it to iTunes before you accidentally deleted it from your device, then a copy of the video is still on your computer.