It started to seem I’d be unable to actually do this. YouTube no longer allows uploads of 24-hour videos. Their time limit now is 12 hours. I didn’t trust YT to seamlessly handle a playlist of four 6-hour chunks of video. I also faced the confusing vagary of how the camera I use for this stuffs in a mysterious extra 6 seconds for every hour of recorded video. Why is this, WYZE?
What I’m left with, after some command line ffmpeg jujitsu, is something like this: