Issue in making animation video

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vpapanik
Posts: 26
Joined: Sat Oct 08, 2016 1:05 pm

Issue in making animation video

Postby vpapanik » Thu May 11, 2017 9:53 pm

I am trying to make an animation video of specific duration (e.g. I have 4000 steps and need to make a video of 20 seconds).
However, I cannot possibly get it to work, I select 'duration', enter 20 seconds, but the produced video is WAY longer than that...

am I doing something terribly wrong or is it a possible bug ?

Thanks a lot in advance !
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miguel
Posts: 344
Joined: Thu Sep 25, 2014 9:04 am

Re: Issue in making animation video

Postby miguel » Fri May 12, 2017 11:55 am

Hi vpapanik,
The thing is that the maximum supported frame-rate when creating videos in GiD is 24 fps. This means that each time-step will last for 40 ms.
If you have 4000 time-steps, the shortest video that you can do with the current GiD is 160 s.

If you want the video to be 20 seconds long with the 400' time-steps, that means that each time-step will last for 5 ms for a frame-rate of 200 fps.

The solution to this problem is to:
- select some time-steps to achieve the 20 seconds limit ( @ 24fps this means use only 1 out of 8-9 time-steps)
- or allow higher fps on the videos ( @ 200 fps may be some video players are unable to show your video, remember that usually the screen rate i 60Hz)
- or a combination of the above 2 options, for instance at 60fps 1 out of 3-4 time-steps will be used.

At the moment this cannot be done in GiD, (it's a known problem), hope to solve it soon.

By now, the only way is to reduce the number of time-steps in gid, or with VirtualDub, or another video editing program, to shorten the video externally.

Another possibility is to generate images from each time-step (you can do it directly from the Animation window), instead of generating a video, and then with an external program, select some of these images ( 1 out of 8-9) to create a video.
For instance using ffmpeg : https://trac.ffmpeg.org/wiki/Slideshow

Best,

The GiDTeam
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vpapanik
Posts: 26
Joined: Sat Oct 08, 2016 1:05 pm

Re: Issue in making animation video

Postby vpapanik » Mon May 15, 2017 9:03 am

Dear Miguel,

Thanks for your prompt reply and your help ! I think that the best way is to skip frames, i.e. run the animation for every e.g. 10 steps.
Is that possible in the animation window or only manually ?
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escolano
Posts: 1568
Joined: Thu Sep 18, 2014 3:31 pm

Re: Issue in making animation video

Postby escolano » Mon May 15, 2017 3:52 pm

No, now there is not any option in GiD to sub-sample (jump) some time steps for the animation
Maybe external tools like the related 'virtualDub' allow force this total time, removing some frames if there are too much.
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miguel
Posts: 344
Joined: Thu Sep 25, 2014 9:04 am

Re: Issue in making animation video

Postby miguel » Mon Jul 09, 2018 8:40 am

Hi,
since GiD version 13.1.8d (the current one is 14.0) this issue has been addressed.
Now the Time length is respected, and will skip the visualization of some time-steps to respect the time length set by the user.
So in the example of creating an animation video of 20 seconds with 4000 time-steps, i.e. 200 time-steps per second and given that the rate is 25fps, only 1 out of 8 will be used to create the animation.
Best,

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