It all began with trying post videos in WhatsApps status. Each block in the status can have only 30s seconds but there is no apparently no way to split a video that is more than 30s long into segments in WhatsApp on the iPhone - not sure how it is in Android land. The very first I mainly split a video using iMovie on the phone, the second time on the Mac using iMovie again. However, my patience for this process ran out by the third time. So I went searching for an automated way to do this 30s split. FFMPEG to the rescue. A quick google search revealed some StackOverflow posts for splitting videos using FFMPEG. I copied the command out of one of the answers and edited it to have a duration of 30s instead of the original 20 minutes.
ffmpeg -i input.mp4 -c copy -map 0 -segment_time 00:00:30 -f segment -reset_timestamps 1 output%03d.mp4
And with one easy command my video was split and saved into 30s video clips.
I put this into a small shell script for future use https://github.com/eeshwar1/splitvideo
And a macOS shortcut that allows you select a video and splits it.
https://www.icloud.com/shortcuts/0b7d511f5e354aa79b294a7d73dc5876