Extracting GPS data from INSV file

[Phil_K]

Hi.

Substracting firt GPS time from last GpsTime give a (gps) movie length of 0:02:10 !!

And all dates in main section are 2023:04:05 07:16:12

When opening file in Studio, it says no gps data from 00:00 to 00:03.

Can anyone help me ?

Well, which recording mode did you use?

There are a few modes, like Timelapse or Timeshift, which playback time is not equal to the recording session time. Timelapse is pretty straight because the interval defines a kind of internal fps but creates a 30fps video. So with interval of 1s recording for 1 minutes gives you 2s playback time.

TimeShift video uses a dynamic scheme to speed up the final video which again is saved with 30fps.

GPS data is recorded and stored for the complete recording session time.
Staying with the Timelapse video example, you get 60s of GPS coverage while the video playback time is only 2s.

If you want to sync GPS and video playback you have to speed up the GPS playback by 30x, or slow down the video playback... for example by re-timing the video to 1fps.

On TimeShift that is much harder to do because of the dynamic scheme used.
Even in tools like Telemetry overlay you would need to speed-up parts of the metadata playback differently.

Now timestamps... it's important to remember that the timestamps in the GPS timestamps the Insta360 cameras up to now use GPST without any timezone data (indicated by the "Z"), which is nearly UTC by a few seconds. Currently GPST equals UTC+18s.

The file dates and media/track times saved in the insv/mp4 are related to date/time of the camera, mostly local time. The cameras get their time by the app. So make sure to connect the camera to the app now and then. The app transfers the time of the mobile device it running on to the camera.

There is a chance that the internal clock of the camera went off a bit.

Depending which way you used for recording GPS data with Insta360 consumer cameras you will face a different delay at the start of a video. Most times there is a gap of ~3s, especially if you use the app to record GPS.

Another thing to note, up to version v4.8.10 Studio2023 has a bug related to GPS data in those time-changed videos like Timelapse / TimeShift. For those Studio2023 v4.8.10 does not take all GPS data stored in the files into account, but only those for the video playback time beginning at the start of the file/video.

Now this is speculation, but I guess data sync is done from end to start. This would allow to determine the starting gap, but creates additional errors for those time-changed video.

That error also reduces data for the GPX export in Studio2023 v4.8.10.
If you need the GPS data in other tools make sure they can read directly from insv files or use exiftool to extract to a GPX file.