> how does it work
Download exiftool Mac .dmg version, install it, and use it via the Terminal.
...using exiftool via the command line is not so difficult as it sounds. Just download the MacOS Package .dmg from exiftool main page and install it via ctrl-click > Open (to bypass the security check for applications that haven't a bought a certificate from Apple). Then, for example, put copies of the images or movies you want to process on the Desktop to a folder named 'test' (don't put anything else there). Then open Applications > Utilities > Terminal.app, type 'cd ' (notice the space) and drag that 'test' folder to the Terminal window and press Return to change to that folder (or type 'cd ~/Desktop/test' followed by Return. '~' means your home folder). Then write or copy & paste a command to the Terminal, press Return, and wait for all files in that folder to be processed. (The dot '.' at the end of the long command means 'this folder'. Or alternatively, omit that dot '.' at the end, and instead type the exact name of the file you want to process. Or type just the start of the filename, and then press Tab to use autocomplete and maybe insert '*' to the end, and hit Return to process all files that start with the same letters. Or add '-ext mp4' switch to the command to process only files that have .mp4 suffix (or add '-ext dv' to process .dv files that exiftool does not touch by default). That was a rather clumsy instruction but I guess you get the idea.
https://exiftool.org/