PC, Mac, Linux
If you're looking for something beyond the usual home computer programs, there is a professional video editing program by Blackmagic Design that can be downloaded and used for free. They sell many products for video capture, etc., and panels that make adjusting video with the software easier. I suppose the software free use is to attract sales for their other products.
A demo on Youtube:
Download here:
https://www.blackmagicdesign.com/support/