1 Topic by sjanssen13

  • sjanssen13
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I have a parser to extract comments and times from several .kva files and combine them to create an averaged timeline. I recently updated to kinovea 2023.1 and the parameters in the .kva file are slightly different now. Previously I used the UserTime parameter in the .kvas to calculate time differences. I am wondering if I could get confirmation on the time calculation using the new parameters. My .kva files has the following parameters :

FirstTimeStamp
AverageTimeStampsPerFrame
CatureFrameRate

And each comment has:
Timestamp

Can times between frames be calculated as:
Time(1) - Time(0) = (TimeStamp(1) - TimeStamp(0))/(AverageTimeStampsPerFrame*CatureFrameRate)

And can time from start be calculated as
Time = (TimeStamp - FirstTimeStamp)/(AverageTimeStampsPerFrame*CatureFrameRate)

2 Reply by joan

  • joan
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There is a JSON export now that should cover this use-case and export times in user-configured units.
You probably also need to take the slow-motion factor into account if the video was captured at high speed and stored with reduced frame rate.

3 Reply by sjanssen13

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Thanks Joan, I had missed the new JSON output which looks like a simpler way for me to get times. It doesn't look like comments are included in the JSON, but I should be able to parse them from the .kva file. One suggestion I have for a future update would be to include keyframe comments in the JSON as well.