How can I recover the recording time from an iPhone time-lapse video?

I set up my iPhone SE version 2 to make a time-lapse video until the battery ran out. The resulting video is 24 seconds long. I'd like to know how much real time this corresponds to. I'm guessing it's around three hours. The calculator at Hustl claims to perform this computation, but the only 24-second time-lapse I can create corresponds to only 12 minutes of real time, which I know is far too little. In the Photos app, the Information pane for the time-lapse video shows the timestamp for when the video was started. Do the individual frames of time-lapse videos have timestamp metadata or something so that I could look at the timestamp for the last frame? Or is there some other way to determine how much real time went by during the creation of the time-lapse video?