user39349: I have some videos which I took during some experimental work which ended up being so dark that the details can't really be seen (these are of spheres hitting a body of liquid and splashing).
It will be a bit difficult for me to re-do the experiments so was wondering if someone  can explain how I can fix these videos (.avi files) to make the details more visible.  The jpegs below are cut from certain frames of the video to show the problem.
 


user39340: The free video editing tool Davinci Resolve will do the job. But be aware that there is already much quality lost in your video files due to the low brightness together with video compression. You will be able to make it bright again, but you will not be able to restore full quality!


Make sure Davinci Resolve is supported on your hardware and platform
Download and install Davinci Resolve
Open Davinci Resolve, create a new project
Load your avi-files into Davinci Resolve and create a new timeline from your video file(s).
Go To the "Colors" tab (at the bottom of the screen) and look for the "Curves" section. Play around with the curves until you like your result.
Go to the Deliver Tab (at the bottom right of the screen) and export your video footage.


39349: <p>I have some videos which I took during some experimental work which ended up being so dark that the details can't really be seen (these are of spheres hitting a body of liquid and splashing).</p>
<p>It will be a bit difficult for me to re-do the experiments so was wondering if someone  can explain how I can fix these videos (.avi files) to make the details more visible.  The jpegs below are cut from certain frames of the video to show the problem.</p>
<p><a href="https://i.stack.imgur.com/foiOr.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/foiOr.jpg" alt="enter image description here" /></a>  <a href="https://i.stack.imgur.com/gkATw.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gkATw.jpg" alt="enter image description here" /></a>
<a href="https://i.stack.imgur.com/FSSvp.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FSSvp.jpg" alt="enter image description here" /></a></p>
 39340: <p>The free video editing tool <a href="https://www.blackmagicdesign.com/products/davinciresolve/" rel="nofollow noreferrer">Davinci Resolve</a> will do the job. But be aware that there is already much quality lost in your video files due to the low brightness together with video compression. You will be able to make it bright again, but you will not be able to restore full quality!</p>
<p><a href="https://i.stack.imgur.com/2f40o.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2f40o.jpg" alt="Screenshot of Davinci resolve showing adjustment curve" /></a></p>
<ol start="0">
<li>Make sure Davinci Resolve is <a href="https://www.premiumbeat.com/blog/davinci-resolve-system-requirements/" rel="nofollow noreferrer">supported on your hardware and platform</a></li>
<li>Download and install Davinci Resolve</li>
<li>Open Davinci Resolve, create a new project</li>
<li>Load your avi-files into Davinci Resolve and create a new timeline from your video file(s).</li>
<li>Go To the &quot;Colors&quot; tab (at the bottom of the screen) and look for the &quot;Curves&quot; section. Play around with the curves until you like your result.</li>
<li>Go to the Deliver Tab (at the bottom right of the screen) and export your video footage.</li>
</ol>
