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 Post Posted: Fri Apr 28, 2017 12:38 pm 
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Joined: Fri Apr 28, 2017 12:08 pm
Posts: 2
When taking Jupiter videos with oaCapture, I've set mistakenly the "gamma" slider to 100%. Actually, it was initially set to 100% in oaCapture, but it was a wrong default position, and after I just touched this slider the image became considerably lighter. So now I have several videos captured with the gamma slider set to 100%, while the most were taken with 50% (the correct value). I want to correct the wrong videos using ffmpeg or another software, but the question is: what gamma power corresponds to slider position of 100%? Obviously, it is not the direct gamma value, because then 100% would mean gamma=1. I've tried to estimate it from the brightness and histograms of the captured images, it looks that 100% means gamma=2 or so, but not very accurate. Is there any official documentation how to derive the gamma power from this gamma slider? Interestingly, what gamma value is set if the slider is moved to 0%?


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 Post Posted: Tue May 02, 2017 2:14 am 
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Joined: Fri Jul 25, 2014 2:43 am
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the default is 50, which corresponds to linear mapping
gamma 0->50:
gamma power: (200-2*gamma)/100

gamma 50->100:
gamma power: (150-gamma)/100

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 Post Posted: Tue May 02, 2017 7:22 pm 
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Joined: Fri Apr 28, 2017 12:08 pm
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Great, thanks! So it appears piecewise linear, rather unobvious...


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