How to join multiple MP4 files from a GoPro with ffmpeg

I recently shot some footage with a GoPro, and realized after the fact the GoPro 'chapters' the footage around 4 GB, so I ended up with a number of 4 GB files, instead of one larger file. There are various reasons for this, but in the end, I really wanted one long file, so it would be easier to synchronize with footage from another camera and my audio recorder.

So I found this answer on StackOverflow, which had exactly the commands I needed:

ffmpeg -i 1.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate1.ts
ffmpeg -i 2.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate2.ts
ffmpeg -i 3.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate3.ts
ffmpeg -i 4.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate4.ts
ffmpeg -i "concat:intermediate1.ts|intermediate2.ts|intermediate3.ts|intermediate4.ts" -c copy -bsf:a aac_adtstoasc output.mp4

Note: If you use the 'High Efficiency' (HEVC) encoder for your GoPro videos, change h264_mp4toannexb to hevc_mp4toannexb in the above commands.

Converting a batch of Dashcam videos into a timelapse

I recently took a family vacation from St. Louis, MO to Branson, MO, and as it was the first time driving with my new Mobius Action Cam Mini dashcam installed on our Toyota Sienna (see a full writeup and review here), I wanted to see if I could quickly whip up a time lapse video of the entire drive.

Driving in St. Louis - dashcam loop gif
A tiny snippet of the final time-lapse video of my STL to Branson drive.