1 Topic by james.stevenson

  • james.stevenson
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Hi all,

I've been using Kinovea to run some lab experiments. We film an object at a high framerate, and get a motion profile of the object by analysing the video. Kinovea has been the only software that satisfies all our needs! Without spending bucketloads...

But I'm running into trouble, I have some interesting errors in the data. It could be due to time-jitter of the frames, but in our analysis we assume they were taken evenly in time. The camera is from Basler, and it should be possible to get hardware timestamps in the chunk data sent from the camera. I think this is nanosecond precision. The trouble is getting those timestamps out into a file that I can use in the analysis. I see timestamps in the mkv file, but they don't look like they have this kind of precision, so I think they are not from the hardward timestamps.

If anyone has any ideas on how to do this, that would be great!

2 Reply by joan

  • joan
  • joan
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Hi,
Just to confirm that the timestamps in the file are not hardware timestamps. This is a topic of interest but so far I haven't looked too much into how to get the timestamps when available.

On a related note I'm also interested in trying to measure the accuracy and stability of the frame rate of arbitrary cameras by independent means (like filming an array of LEDs flashing at known frequency to create a binary clock). With the goal of controlling the assumption that the frame rate is stable and that time fluctuations are extremely small or at least much smaller than other sources of error.

Aside from small frame rate fluctuations a possible source of error is when a frame is completely dropped from the output. There should be a drop counter in the info bar of the capture screen. A single frame drop will throw inter-frame arithmetic out of wack. Using recording mode "retroactive" should help if the duration of the recording fits in memory.