1 Topic by joan

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When using a high-speed camera, you can currently configure Kinovea to show you the times expressed in the real action timeframe.
(So when the position label says "1 second", it's 1 second of action, not one second of video).

Currently though, the little slider for speed percentage is still relative to the video timeframe. If you set it to 5%, it just means the video is displayed at 5% of its original framerate.

What might be interesting is to have the speed percentage to be also expressed in the action timeframe. Then when you ask 5% it would mean that the performance you are watching is progressing at 5% of the speed of the real action.

I'm not sure if that was clear… To picture it, say you have captured at 250fps and the resulting file is 25fps. Then by default the middle of the speed slider would say 10% not 100%.

Would that be interesting ?
Should that be the default when you have configured for high-speed camera?

2 Reply by fil-archery

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I use an high-speed camera every day and I think will be great to have the chance to chose the number of fps of each video because I change the frame rate many times and I think could be an interesting new feature!

I say this because now is easy to find HS cameras with small price!

In any case congratulation for your great job!

3 Reply by joan

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Well, if you have captured at say, 210fps, you can configure this by right clicking the image, and then menu "Set Original Speed…" and put 210 in the box.
(yes, the name of the menu is not the best… that will probably change to something like "configure for high-speed camera" smile).

The speed slider however, will still be expressed in % of the video speed. I'm wondering if it would be better to express it in % of real action speed.

4 Reply by fil-archery

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ok
I'll try as soon as possible!

For the menu I think you could use "configure fps" or "HS camera", it's easy and short!

5 Reply by CAR_UARD

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Does anyone known if is it possible to measure real speeds when Video rate is configured at 300 fps?.. We have realized that stopwatch detects when frame configuration is changed, but measuring distances does not. ( Once the video is calibrated, speed measurement is exactly the same rather the video is at 25 fps or 300 fps)

Is it a methodology problem or the software does not support that option?

Thanks in advance

6 Reply by joan

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CAR_UARD wrote:

Once the video is calibrated, speed measurement is exactly the same rather the video is at 25 fps or 300 fps

I'm not reproducing this issue… If I have a tracking path configured to display speed, and a calibration line somewhere, each time I change the framerate through "High-speed camera" menu, the speed displayed on the track reflects the change. Is it the right context ?

You do need to have a calibration line somewhere, otherwise the speed is in pixels/frame and that doesn't change with the framerate.

7 Reply by CAR_UARD

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I have retried and changes are not visible.
Are these the correct steps?

Choose a video at 300fps / Draw a line / Calibrate the measure/ choose a point to follow / create the path / stablish the setting to visualize (speed). and finaly when evertything is set, I go to Set original speed and write 29,97 fps.

Stopwatch reflects the changes but nor does the speed.

Could I send you a screen video (any mail)  to check if everything is OK?

Thanks a lot in advance

8 Reply by joan

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CAR_UARD wrote:

I go to Set original speed and write 29,97 fps.

In this dialog, you should set the frame rate at which the video was captured.
It is common for example that a video is captured at 300fps and the resulting video file plays at 30fps. In this case, you would set "original speed" to 300, and it will say "video is 10x slower than original."

Ah, yes, I get it. This had no effect at some point and has been fixed after the version 0.8.7 was released. So you'll need to use the experimental version.
It was discussed in this thread : Ball velocity calculation with non 29.97 fps video

9 Reply by tirosh

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Hi,

Just started to use Kinovea with captured high speed video of 210fps.
When i adjust the Set Original Speed option the video is playing slow motion at 100% speed.
If i need to play the video as in normal real world speed i will need to adjust the speed x8 faster.

1) unfortunatlly the speed can be adjusted only to 200% faster (i.e x2) but i need x8.
2) It would be nice also to save a new video that will play like normal i.e convert the video to 25fps so it will play normal in other media players.

10 Reply by joan

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Hi,

First of all, I will use this opportunity to say that the idea initially discussed at the top of this thread has been implemented in the latest experimental versions.

So when you have a 210fps video configured, the speed slider will actually not go from 0 to 200%, but from 0 to 28.5% (if the video file is crafted as 30fps).
And the speed percentage will refer to the percentage of speed relatively to the actual action.

So your issue becomes "how do I get back to 100%?".

Unfortunately, it's not simple. It was also asked a while back on the french part of the forum, and the issue I found then is that all the frames creating the slow motion are to be decoded anyway. We can't just skip 9 frames out of 10 to go 10 times faster. We have to decode everything (to reconstruct a given image, information from the previous ones is needed).

In this case this means decoding 210 images per seconds, even if we only render some of them to recreate the illusion of normal speed.
It will be extremely hard to keep the pace. For videos shot at 300, 600, 1200 fps or more, it will just be impossible.

Currently I don't see a real time solution to this. The only thing we could do is your point 2, create a new video and decimate frames on the way.
In this case we could recreate the original motion. It would be like creating a timelapse video of a slow motion smile

11 Reply by tirosh

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1) i was thinking of extending the speed percentage slider to 300 or 400%. I know that there are activeX controls that can do this. For example VideoCapX has a function PlayerSetRate(NewRate As Double) in which you can set 3.5 faster.

2) The ability to create a new video and decimate frames on the way will be great advataged feature in my opinion.

3) Where can i download the experimental versions?

Thanks,

12 Reply by joan

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tirosh wrote:

3) Where can i download the experimental versions?

Sticky thread at the top of this section. "Experimental version - XXX"