I needed to join a bunch of video files together. They had all the same dimensions (720p), same video codec (h264), and the same audio codec (AAC), so I didn’t want to reencode the files. Ffmpeg can do it. It took me a bit to find the right syntax as I’m on Windows, but I found it.

ffmpeg.exe -i list.txt -c copy output.mp4

Here’s an example of the list.txt (because it’s not just a list of the files):

file ‘file1.mp4’
file ‘file2.mp4’
file ‘file3.mp4’

Here is the documentation of it. I also used this stackoverflow thread. Ultimately, I had to use the file method because I couldn’t list the files in the command line and get it to work. (i.e. ffmpeg -i ‘concat:file1.mp4|file2.mp4’ -c copy output)