Author Topic: Software for measuring velocity  (Read 3146 times)

rdemyan

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Software for measuring velocity
« on: May 17, 2022, 02:41:27 PM »
Hi:  Can anyone recommend software for measuring velocity on a video shot using a  Chronos camera.  I'm measuring the movement of waves, so I would think the software needs to be able to move forward frame by frame.  I would like to be able to extract the frames as needed.  Also, I'll need to be able to draw a line on the video which will act as a ruler.  The line needs to show up on extracted frames.

Also, in video editing software, when advancing frame by frame, does the software for a typical program like AVS Video editor know what the frame rate was that the video was shot at (not the playback FPS).  I seem to be seeing some discrepancies.

Nikon1

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Re: Software for measuring velocity
« Reply #1 on: May 17, 2022, 02:46:52 PM »
need to look that up, seen some Free software that can do that, i think to remember, but there will be no software able to tell you what FPS it was Shot at on the Chronos, as that Data is not Saved to the Footage/ Files. Only thing preserved is the Shutter-Speed, meaning duration of time that the Single Frame was Exposed for, when Saved as DNG Format. But no Framerate info Anywhere. So you will need to either Write that down to Paper/ some Table or make notes on the Filenames When Saving, if you want to be sure of that information at some point later in time. Maybe that Will be eventually added to Firmware, that we will also get that Info saved to the EXIF Data of the File, but currently you need to do that by yourself manually.
 .
 #EDIT:
 Cant find any Free Software right now, only paid ones, which i assume to be expensive.
 /EDIT
« Last Edit: May 17, 2022, 03:03:14 PM by Nikon1 »

rdemyan

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Re: Software for measuring velocity
« Reply #2 on: May 17, 2022, 04:08:34 PM »
I did write down the FPS as mentioned in my example in the original post.  Why do you think there is a discrepancy.  Also why do you think pressing the "next frame" button in AVS editor doesn't actually advance the frame until, in this particular case, eight presses of 40 milliseconds each are required to advance the frame.  I wonder if there is some kind of calibration that I need to do.

Nikon1

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Re: Software for measuring velocity
« Reply #3 on: May 17, 2022, 04:21:51 PM »
sorry, maybe i didnt understand correctly what you are trying to say there.
 But if the Framerate it was recorded at is known and the Framerate of the Saved File (in case of a Video File) is known, and there is A difference between expected Time Frames Show up to when they actually do in a Video Editor, you should check, what Framerate the Footage is (given you feed your Video Editing Software a Video File, and not Single-Frame Formats) and if that is the Same, at what the Video Editor is set at.
 There are Several different commonly used Framerates which are almost the Same, but not quite. For example 25fps 29,97fps and 30fps. If there is a Mismatch, Weird Frame Skipping or miss-Alignment can happen.
 That would be the only thing i can think of right now. Not Particularly Familiar with the AVS software you are using, and 40ms x 8 would be 1/3 of a Second, which indeed seems weirdly long for a single Frame to last.
 Maybe you have some kind of time Stretching effect on the Footage?
 Other than that, i would need to actually try to Download and install AVS, and reproduce your issue. In that case, some kind of Project File/ The Source File you are using or at least a Screenshot and some info about the Original Footage File you are using would help a lot.

Nikon1

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Re: Software for measuring velocity
« Reply #4 on: May 17, 2022, 04:39:55 PM »
Did just Download AVS, and install it. For me it works perfectly fine, to advance a single frame at a time. Push of Arrow Right will advance 40ms, and a single Frame of the Footage at a time, for Footage Recorded on the Chronos 2.1, saved at 25fps.

rdemyan

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Re: Software for measuring velocity
« Reply #5 on: May 17, 2022, 08:43:02 PM »
I don't understand.  If I recorded my footage at 5407 fps and played it back at 60 frames per second is that different than if I had set the Chronos 2.1 to playback at 25 fps.  Isn't the playback rate independently set from the recording rate.  And for what I am trying to do, the only thing that should matter is the recording fps, i.e. in this case 5407 fps.

A different question:  Is there a way to check the accuracy of the fps on the Chronos 2.1?   Thanks.

Nikon1

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Re: Software for measuring velocity
« Reply #6 on: May 18, 2022, 01:44:11 AM »
It is Very much different.
 Lets assume you Recorded a Sequence of 100 Frames at a Framerate of 5407fps. That would have taken about 0,01849... Seconds Realtime to Record that.
 Now to Play these 100 Frames Back at 60fps would take 1,6666... Seconds.
 To Play the 100 Frames Back at 25fps would take a Full 4 Seconds.
 Meaning, 25fps will seem to be more than twice as slow, but the 60fps Playback will be much more Smooth.
 . 
 A more detailed Explanation regards Playback Framerate can be found here:
 https://forum.krontech.ca/index.php?topic=692.msg4769#msg4769
 Here you also have Gavin explaining basically the Same thing, in even more Detail as a Video with Examples and Stuff:
 https://www.youtube.com/watch?v=71t_MCJ2_XI
 .
 .
 Regards Accuracy, i will link this Thread, which talks about the 1.4, but should be basically the Same for the 2.1 too:
 https://forum.krontech.ca/index.php?topic=552.0
 As far as i understand it, its basically timed after the internal Quartz Clock, but the Single Frames could have some very small amount of Deviation from that, but over Long Term, it should be crazy Stable and Accurate. In short, i would assume, that if for some Reason your needed Timing was anywhere close to as precise as the Chronos Cameras themselves already are, you would probably want to Trigger them Externally anyways with a more Precise Clock (This might be overkill, but you get the Point):
 https://youtu.be/eOti3kKWX-c?t=1174
 For almost anything else, especially most general Purpose Applications, timing and Framerate Accuracy of the Chronos Cameras should be Plenty Precise enough.

rdemyan

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Re: Software for measuring velocity
« Reply #7 on: May 18, 2022, 07:50:20 PM »
I'm currently testing a free software program named "Tracker".

https://physlets.org/tracker/

It might do the trick, but I wish it had more features.

Solscud007

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Re: Software for measuring velocity
« Reply #8 on: May 19, 2022, 08:46:31 AM »
I find it helpful to look up the size of my videos/images.  Then I look at the resolution chart. 800x600 sized image means I filmed it at 2873 FPS. Assuming you did not enter a custom frame rate.