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Thread: Video and Data Time drift

  1. #1
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    Video and Data Time drift

    All,
    I am here to share another problem I have noticed and now I had the time to identify it. Maybe I have been doing something wrong and you guys can help. My setup is easy: video coming from GoPro Session 5 and data coming from my Aim Solo. The data from the Aim are exported using CSV motec compatible format. GoPro is saving 30fps Full HD

    When I sync the two on a video of 10 minutes, the first 2 minutes are out of sync a bit (few seconds) while the remaining 8 minutes are perfectly in sync. Do you have any idea of what is happening?

  2. #2
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    I found the issue by myself and it is a strange one. The problem is on the AIM Solo data specifically to the first lap when starting from standing. I am guessing their internal algorithm does something strange during the calculation. Long story short, the video shows a first lap of around 2:05 and the data shows a first lap of 2:08...that's why of the initial drift. To fix the data before exporting it in csv you have to go RS2Analysis, go into the lap manager tab and click on the top right --> GPS Lap insert. At this point I have selected to use start/finish line from database and I selected the right track. Click continue and now all the lap times are recalculated. After this calculation, first lap was 2:05. I am so happy!

  3. #3
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    I noticed the same driftiness with lap data whether it comes from the GoPro cameras or using the actual lap times from a race and overlaying the data on the video. Some of my videos intermittently slip in and out of sync with the finish line after syncing the first lap. I am assuming that there could be a timecode /FPS issue with the video source file even though all files record at 30FPS.

  4. #4
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    I had the same idea and that's when I check the actual video lap time vs the one from the lap timer. In my case the lap timer had an issue, with the trick described above everything went to normal

  5. #5
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    Okay, great. I'll check it out! Thank you

  6. #6
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    Quote Originally Posted by gian84 View Post
    I found the issue by myself and it is a strange one. The problem is on the AIM Solo data specifically to the first lap when starting from standing. I am guessing their internal algorithm does something strange during the calculation. Long story short, the video shows a first lap of around 2:05 and the data shows a first lap of 2:08...that's why of the initial drift. To fix the data before exporting it in csv you have to go RS2Analysis, go into the lap manager tab and click on the top right --> GPS Lap insert. At this point I have selected to use start/finish line from database and I selected the right track. Click continue and now all the lap times are recalculated. After this calculation, first lap was 2:05. I am so happy!
    You dead set legend! I've been fighting with this for ages now with an Aim Solo jaabubby assumed it was some strange fps variance between the Aim Solo and Gopro. I was resorting to slowing the data by 1% or something like that in RR settings to sync it. Will try this on my next video

  7. #7
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    Quote Originally Posted by AussieMSM View Post
    You dead set legend! I've been fighting with this for ages now with an Aim Solo jaabubby assumed it was some strange fps variance between the Aim Solo and Gopro. I was resorting to slowing the data by 1% or something like that in RR settings to sync it. Will try this on my next video
    A valiant guess and err on my part. Let me know how it works. I haven't had a chance to pull up my old files to see how this can be done for future projects.

  8. #8
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    Quote Originally Posted by AussieMSM View Post
    You dead set legend! I've been fighting with this for ages now with an Aim Solo jaabubby assumed it was some strange fps variance between the Aim Solo and Gopro. I was resorting to slowing the data by 1% or something like that in RR settings to sync it. Will try this on my next video
    I am very happy other people had the same issue, I was going crazy too. Did it work like in my case?