cgsecurity.org

I had originally tried to use the option as stated in the PDF

When using PhotoRec, in FileOpts, enable
[X] mov/mdat Recover mdat atom as a separate file

However this was causing the same issues, which is my MP4 files would not play.
But then I saw this just a few paragraphs below:

This solution works only for videos written in two fragments. Videos from GoPro HD2, Hero3-Black Edition, HERO4
Silver are stored in more than 2 fragments, so special software solutions are needed to recover such videos. This chapter
does not concern copies or downloaded files, only files written by some digital camera, not by your computer.

I could not find any other references to GoPro videos in here sadly. So anybody know how/where to do it or find the information to help

You might try a different browser because mine finds a couple of references when keying "Gopro" into the search box in the top right corner.
If your search does not work you still have to option use a commercial alternative offered by the author of Testdisk and owner of this site:

https://www.cgsecurity.org/wiki/Service ... nn%C3%A9es

The price is EUR 200,- for video recovery from a recent GoPro camera according to the linked page above:

Récupération de vidéos d'une carte mémoire de caméra GoPro récente (exemple Hero 3): 200€

You can contact the author by using the "Contact Us" button on the bottom of this page.

Ha! Thank you for your response. I was talking about https://www.cgsecurity.org/testdisk.pdf but I see what you did

The gopro search did not mention any special ways to recover for a gopro. The files are not "required" as it were. But it would be nice.