1 Topic by samuel

  • samuel
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Hi,

I need to analyse continuous x-ray images as part of my work. I previously would analyse them in VLC with nil major difficulties however there was no option to move backwards frame by frame. This brought me to Kinovea.

I downloaded Kinovea today to test the video analysis and I've found they're playing at double speed. The x-rays themselves run at 30 fps but when uploading them to Kinovea they are playing back at 59.94 fps. When I checked the video files themselves, I realised they're saved at 59.94 fps, but when putting the same file back into VLC it plays with nil difficulties.

I thought adjusting the time calibration would fix this, but it just changes the time it's saved as.

Am I missing anything? Is there a quick fix?

Cheers

2 Reply by joan

  • joan
  • joan
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For now I would say just set the playback speed to 50% (use up/down arrow keys to land on exact percentages), if it's possible for your use case. And if you are sure the videos were captured at 30 fps you can set that in the time calibration dialog so the timestamps, time intervals, speed measurements, etc. take it into account. Time calibration doesn't touch the internal video frame rate used for playback.

Sometimes the file format container and the video codec disagree maybe it's one of those cases. Unless the video is interlaced in that case you would see artifacts and you would need to do Image > Deinterlace.

Not familiar with continuous x-ray images, is it imaging someone/something in motion or is it the tool that is moving and scanning at different depths/locations? Where is the 30 fps information coming from? Is it 30 or 29.97?