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Frequency/Signal of the pulsating light in a video

Last Modified: 2016-08-03
I have a video with an LED pulsating on/off.
Just by looking with the naked eye I estimate the frequency somewhere in a visible spectrum 2-10Hz.
I would like to know with a higher precision the frequency.

Do you know any software for Windows or a trick/procedure how to find that frequency?
If I would be able to extract the signal on/off as a curve (rectangular signal) vs. time, that would be even better. It would be perfect.

What crossed to my mind up to now is only to split the videos in frames and to look how many frames are with LED on and how many with the LED off. Then knowing the frame rate I could calculate the frequency of the LED light or even to draw the signal. But that seems a Sisyphus work.
The problem is that frequency is not even constant.
There is also „flicker tester” software (http://www.visosystems.com/products/flicker-tester/ ). But I do not know if I can point that to my monitor, because the monitor has its own flicker frequency. I do not have access to the original light source. I have only a recorded video.
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