I just tried out RaceChrono a couple of weeks ago and also recorded some video on my Hero 6 Black. I signed up for the Pro trial and tried to import the video from the GoPro. I can get it synced up to the start/finish line, and fine tune it with the +/- 50ms buttons in the first couple of corners so that it matches the accel/decel curve, but by the time it gets to the end of the lap, the video is always a couple of seconds ahead of the session data recorded by RaceChrono.
I've tried both the original GoPro MP4 files and my post-processed combined video file with the same results either way. Am I doing something wrong here? The video is 1080p60 and my phone is a Pixel 1. This doesn't seem like a slow video playback issue, since the video is faster than the session data.
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Easiest way is to sync according the finish line if it's visible in the map. Or maybe some other landmark visible both in the video and the map. Take a look if the video sync stays same lap-to-lap. GPS data quality might affect too, so if your data is not very good, then it will make the sync harder, and the lap timer accuracy will suffer.
If you want me to take a look, then please share DropBox/Google Drive links to the session (.rcz share) and the raw GoPro videos linked to your session.
my hardware: Gopro hero4 silver @1080/60, carista obd dongle, Garmin Glo GPS.
files (mp4 video got another 40mins left of upload - 2.3GB):
https://drive.google.com/drive/folders/1AL6L98lH3zorQCuqrNW7J0pHezQ-WOje?usp=sharing
I will email you the "fixed" session. Try that on your phone and let me know if it fixed it for you too. If not then the video might be played back too quickly on your phone, but not on mine (Nexus 5x).
But that said, I've seen such thing happen, that video is played back too fast. In that case the problem turned out to be that the camera created video files that played back exactly 60 fps, instead of 59.94 fps. This meant the videos were played back 0.1% faster than they should have, which meant that every minute there was 60 ms added delay. The fix was to switch the camera to 50 fps which is available on most cameras when switching from NTSC mode to PAL mode. And I need to point out that camera was not a GoPro, but some cheap random one.
I'm using a HTC10 phone. if it is a device problem, then i'll try some other android devices and see how cope.
Next version will have import functionality that you can open files directly from within RaceChrono.
was there anything obviously wrong when you looked at it, and is there anything i can do by myself to fix it?