Getting Slow Motion meta data from captured video in iOS

We have a video app that is importing video from the user's camera roll. Our problem is importing slo-mo video taken with the native Camera app. We can recognise that there is a higher than normal frame rate (e.g. 120 or 240 fps).

What we can't find is the meta information that specifies when the video drops into slow motion and when it speeds up again. Does anyone know where this information is kept, and/or how to get at it? Is it in the file itself, or stored in a separate meta file somewhere?

Any help would be hugely appreciated, thanks!

How do I export slow motion video from iPhone?

Open iMovie, load your slow mo video in a project, no need for filters or text etc. Now go to your export screen, select the upload button. Scroll down and select: "keep video" or "Save file".

Can you make an iPhone video slow motion after its recorded?

In the Photos app , you can trim a video you recorded on your iPhone to change where it starts and stops. You can also adjust the portion of a video that appears in slow motion when you record in Slo-mo mode.

The slow motion segments are technically not metadata. They are of type UITrackSegment which you can read about here

The result of a scaling method on a track creates a timeMapping object that plays the track at the rate of it's source.duration / target.duration. You can read more about that in this blog post.