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I am using a GoPro Hero 4 to record groundtruth videos. I need to collect the exact time the video has been created (down to miliseconds).

In ext4, there is a field of birthtime ( or ctime, btime). Could I format the SD card to ext4, and stat the birth time later?

Dzung Nguyen
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  • Did you found any solution? – Raphael Ottoni Jul 20 '17 at 17:59
  • No. I ended up creating sync events (play sound, flash LED) periodically from a phone to help syncing time. – Dzung Nguyen Jul 21 '17 at 03:16
  • Have you tried use the timecode embedded with the codec? If you use ffprobe on the MP4 it will show. Timecode is a time synchronization data in the format of hours:minuts:seconds:frame ... so the frame value says which corresponding millisecond it started to record. So if you use the rule of three to calculate the corresponding millisecond regarding the FPS you set to record it may work =) – Raphael Ottoni Jul 21 '17 at 04:01
  • Just to add some info: The file system go pro uses is exfat and it also store the birth time. You can access this using stat from gnu (not the currently implemented with Mac OS)... if you are using mac, just "brew install gsat". The problem is that GoPro actually doesn't save the milliseconds, it apears to use that timecode data instead. – Raphael Ottoni Jul 21 '17 at 04:03

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