Images sampled from GoPro split videos repeat the timestamps for each video segment

Reproduce the issue with the sample_video command and split GoPro files, then trace the timestamp handling used by that entry point. Done means successive video segments produce continuous EXIF timestamps rather than repeating the first segment's start time.

Basic information

• Release version: main (but with a fix applied first from https://github.com/mapillary/mapillary_tools/issues/503)
• System: Windows 10 Pro x64
• Capture Device: GoPro HERO8 Black HD8.01.02.50.00

Steps to reproduce behavior

1. Have a video recorded on GoPro Hero 8 long enough to be split into 2+ files, i.e. videos/GH01####.MP4, videos/GH02####.MP4, etc.
2. Run image sampling from video, for example mapillary_tools sample_video "videos/" "images/" --video_sample_interval 1

Expected behavior

images/GH01####.MP4/ folder has image files with EXIF timestamps 2022-05-28 18:00:00, 2022-05-28 18:00:01, etc.
images/GH02####.MP4/ folder has image files with EXIF timestamps 2022-05-28 18:09:10, 2022-05-28 18:09:11, etc.
etc.

Actual behavior

images/GH01####.MP4/ folder has image files with EXIF timestamps 2022-05-28 18:00:00, 2022-05-28 18:00:01, etc.
images/GH02####.MP4/ folder has image files with EXIF timestamps 2022-05-28 18:00:00, 2022-05-28 18:00:01, etc.
etc.

Additional information

I believe the problem is that my GoPro 8's split video segments all have the same stream/track creation date metadata. For instance, both videos in the above example would have "Media Create Date" set to "2022:05:28 18:00:00". So my GoPro doesn't actually record each segment's creation time, but only the creation time of the whole recording.

I tried various parameters and combinations, but didn't get anything to work. I tried seeing if there was some place where the code would handle something like this, but also didn't see anything.

What I did locally to fix this (https://github.com/RudyTheDev/mapillary_tools/commit/75620445aca75f662dab6f3f94fe1e0a498feff3) is to keep the total elapsed time and offset every consecutive video by that amount. This is a quick-and-dirty fix that doesn't know anything about the video sequence or GoPro logic, but this does produce the correct/expected timestamps for me.