I’m pretty sure iPhones do put it in. You should exif dump an iPhone XS image. INSANE what’s in there.

Go on...

This would (maybe) help with a common thing my wife does when taking videos: Start recording in portrait mode, then realize you did that, and rotate the phone 90 degrees to get widescreen video (but without restarting the recording).

When you play it back on a phone (with auto-orientation mode on), starting from holding the phone in portrait mode (as you normally do):

* it starts playing back as portrait, which looks fine

* the video rotates (because the camera was physically rotated), so now you're watching a widescreen video that's 90 degrees off

* Your natural reaction is to flip the phone 90 degrees to make down "down" again, but this changes the phone into widescreen mode, and because it thinks it's playing a portrait-style video, it changes to portrait-in-widescreen mode, and now the video is again tilted 90 degrees but 1/3 the size with huge black bars on either side

If you play it back on a computer/TV, you get the same end result: a widescreen video that's rotated 90 degrees, and 1/3 the size with huge black bars on either side.

Can't help you with the video-taking technique but when playing back the videos, if you hold the phone so that the video matches the screen, then rotate it so the screen is upwards, you can then spin it so it looks the right way up as long as you keep the screen vertical enough.

In these cases I just enable rotation lock.

Haha! I guess one has to cut the video and rotate manually one part?

Might as well put in acceleration and rotation while we're at it.

Pitch and yaw

You're joking, but many smartphones encode gyroscope readings in the metadata.

And uptime seconds (!?)

And estimated distance to subject, AGPS information, GPS acquisition time, depth field metadata, current battery level, operating system version, ...

We can use both sets of names, better yet, mix them!

Ah, the famous ropitchaw vector!

Won't help when filming in the ISS. Microgravity or not, I would like to view the result in the same orientation as the crewmember who filmed it.

And how would the camera know without gravity?