1 Topic by cullenjd

  • cullenjd
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Hi Joan,

I'm looking at a video clip which is about 50s long in ver 0.8.7.  There are several times where I want to use the video controls to back up a number of frames and review. I'm able to back up about ~ 20 frames and then the button and cursor key stops working.  The video will not back up any further.  Any ideas?

Thanks,

John

2 Reply by joan (edited by joan 2010-05-23 13:31:18)

  • joan
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Hi,
Yes, it happens sometimes. There can be two reasons:

- The frames are not evenly spaced in time in the file.
When Kinovea tries to go the preceding frame, it computes the time position for it, and seek back to it. (The seek generally moves a few frames back and then the play head is moved forward again until we pass the target frame.)
When frames are not evenly spaced and the preceding frame has a bigger interval than the average, what can happen is that basically we don't realize it is the target frame (we think there is another one between it and the current), we keep going forward for the target, and end up on the current frame.

I'm not sure that paragraph was very clear, but the bottom line is that I think this is a defect in Kinovea. It should detect this type of issue and maybe try to go back 2 frames at once or something, to unstuck the situation.

- The other reason is when the file is broken or does not support seeking well. For some files (VOBs from DVD are an example) seeking does not work all the time. It may even happen that seeking back actually moves the playhead forward!
There is some protection code against this, but sometimes it's just impossible to fix.

I think you are experiencing the first issue. I'll add a bug to the tracker not to forget looking into it.
edit: m206.