Joining GoPro video files together automatically

GoPros split up large video files into chapters, joining them back together into a single, large file is a bit fiddly.  Here's how to do it automatically using the Automator application I created (StitchGoProSession.app)

tl;dr;

Install ffmpeg using Homebrew and then drop the folder containing your GoPro chapters onto the Automator application StitchGoProSession.app

The details:

There are a few moving parts, the most important is to have ffmpeg installed.  I did this using Homebrew and the bash script in the Automator application depends on that path.  It's easy enough to change in the script, which is listed below.

Essentially the StitchGoProSession automator application is a wrapper round the bash script, but the first step is 'GetFolderContents', which produces a list of the files in the folder, which are then passed through to the script.