concatenating go pro mp4s

Hey, there, I recorded a bunch of long videos with Go Pro. It splits them at roughly 4GB. So, every 34 minutes or so it creates a new file. I want to put them together into a single long file. Have been having no luck with *avidemux 2.5.6; it adds garbage at the split points *mp4box that comes with the latest Yamb 2.1.0; it seems to write out the file fine until it gets to the very end at which point it throws an unhandled exception, and even though I can see the 13GB "temp output file" in the explorer window, it's already slated for deletion, or something. I probably should discuss the mp4box problem on the yamb 2.0 thread, but it seems no one is monitoring it anymore. But this post is to do with any suggestion that works that concatenates Go Pro Mp4s without any glitches. thanks BTW, here is the copy of the Yamb.log Code:

Well did you try the latest mp4box build ? Not the one that gets shipped with Yamb ! Replace the old one with this ->

Nope - will try - thanks.

Ok, so after installing that GPAC thing from the link you gave I got the mp4box in it to process the command line above i.e. Code:

thanks: -add must be -cat. And I also decided to just do simply mp4box -cat <first mp4> -cat <second.mp4> etc. Worked fine in my case.