1 Topic by Sportability

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Hi,
I am a new Kinovea user and I LOVE what it does and how intuitive the interface is.  I'm still working out some growing pains, tho...

My biggest problem is saving a video and reopening it for editing later.  The Key Frames seem to be 'off' when I do this.

Example:
I have a 20 second video running at 100% speed, and I create key frames (with text or angle marks or lines) at 4, 7 and 14 seconds.
If I save the video as a MKV with key frames painted, then it is just fine, but obviously it is no longer editable if I want to change the info in the key frames.
But if I save the video, close it and reopen it, the Key Frames no longer sync up with the video.  They show progressively earlier at 3.5, 6 and 11 seconds. 

Any ideas what I'm doing wrong?

2 Reply by joan

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Hi,
At first I would say this look similar to bug 214.
It does that for some files, still trying to find a workaround.

In the meantime, what you should do is save the keyframes in their own file. Choose the last option on the save dialog, and it will create a .kva file containing data of the keyframes, drawings, comments, etc.
If you keep the defaults (same name and same folder as the original video), it will be automatically opened and loaded when you reopen this video.

However, your de-synchronization seems to be pretty important, maybe it's a different issue. If possible, attach a small video sample to the bug (less than 1MB).

3 Reply by Sportability

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Hi Joan,
Thanks for such a prompt reply!  I read up on bug 214, and it does seem similar. 
Saving the keyframes in their own file did not help - they are still offset when loaded.  Here is some updated info:

The raw video was taken on a Sony minidisc camcorder and then converted from the minidisc's native .vob format to .asf.  When I load the .asf file into Kinovea the video is 2m:19s:48 long.  If I choose to view/edit the fps, it says the video is at 25fps.

I just placed a keyframe with an angle-mark on it near the very end (2:19:36) and saved it as a Kinovea .mkv  When I closed and reopened the .mkv, the keyframe is still at 2:19:36, but now my video is 2:47:40 long (an increase of 35%), and the keyframe is no longer 'lined up' properly.

If I save the keyframes to their own file and load them they show up at the correct time, but if I have saved the video, then the correct time is no longer in the correct spot because the video is 'stretched'.

Obviously, Kinovea is not adding 28 seconds of content to my video (altho that would be a neat trick), so i think there is some translation between fps in my original file and fps in the saved .mkv.

Last - I just pulled a random .mpg video file and loaded it into Kinovea, saved a keyframe and reloaded the work and it looks just fine.  Is it possible that the problem is with my .asf file, or the way Kinovea reads it?

Thanks (again!)

4 Reply by joan

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If it is indeed a similar issue than bug 214, then yes, the problem is during saving the file to MKV.
We specify the initial fps, for example 29.97fps, and it is somehow changed to 30fps (only some specific fps are subject to the issue).
The final video contains the same number of images, but they are not aligned with time anymore.

Seeing the large shift and the fact that it goes the other way, your issue may be a different one.
Also, if you didn't reencode the .asf and when reopening the key images are still offset, then it is definitely a different issue.

If possible, create a very short video on the camcorder, like 1 or 2 seconds, and do your conversion to .asf.
Then attach the .vob and the .asf to bug 214, or send them by mail to: joan at kinovea dot org. Thanks smile

Also, the .vob might be readable directly in Kinovea if it's an option.