commandline editing for zoom meetups

In the last year, I've helped host a bunch of meetups and conferences on Zoom. We've recorded them, and I wanted to turn each talk into a separate YouTube video.

Zoom can give you a giant MP4 of the whole session, and I wanted to cut that video into pices.

A few times, I tried using OpenShot but: my laptop struggled to cope with the load; the UI was focused on more interesting editing than what I wanted; that UI isn't natural for me, who spends 99% of my time not using editing software.

I figured out a workflow that worked better for me:

• Use VLC on the giant MP4 to quickly identify the start and end times for each talk.
• Make an ffmpeg command line for each talk, for example:

  ffmpeg -i day1.mp4 -ss 2:31:54 -to 2:47:07 day1-7-madany.mp4
  ffmpeg -i day1.mp4 -ss 2:47:16 -to 2:57:46 day1-8-foster.mp4
  ffmpeg -i day1.mp4 -ss 2:58:17 -to 3:13:10 day1-9-glanzman.mp4
  ffmpeg -i day1.mp4 -ss 3:13:34 -to 3:23:42 day1-10-ward.mp4
  ffmpeg -i day1.mp4 -ss 3:24:02 -to 3:33:22 day1-11-reynier.mp4
  ffmpeg -i day1.mp4 -ss 3:45:52 -to 4:13:18 day1-12-clifford.mp4
  ffmpeg -i day1.mp4 -ss 4:15:17 -to 4:55:14 day1-13-shaffer.mp4
    

  which will copy ranges out of `day1.mp4` in to the named file.
• Then, let this run. It's quite slow on my laptop but doesn't need any human interaction.