How to automatically add chapters to your podcast

A frequent request from listeners of my Breaking Change podcast has been for chapter support. At one point, I tried to manually incorporate this into my (extremely light) editing workflow, but it was fiddly and error-prone to do manually.

That is, until yesterday, when I had the thought, "what if I had a script that could detect each time the audio switched from mono to stereo?"

See, like most podcasts, I record my voice in mono, but the music jingles (or "stingers") are all in stereo. And because each mono segment is punctuated by a stereo stinger, the resulting timestamps would indicate exactly where the chapter markers ought to go.

So, an hour later, some new shovelware was born! I call it autochapter, and you can install it with homebrew:

brew install searlsco/tap/autochapter

Once installed, just pass autochapter your chapter names as a text file or a list of flags, like this:

autochapter \
  -s Intro \
  -s Follow-up \
  -s "Aaron's Pun" \
  -s News \
  -s Recommendations \
  -s Mailbag \
  -s Outro \
  v44.mp3

And you'll get a remuxed version of the audio file (e.g. v44-chapters.mp3), as well as textual readout of the chapters, ready to be pasted into your YouTube description:

Chapters:

0:00 Intro
24:11 Follow-up
53:45 Aaron's Pun
56:14 News
1:49:03 Recommendations
2:03:52 Mailbag
2:33:11 Outro

As you might surmise from the examples, v44 of the show is the first version to ship with chapters.

And that's about all there is to it. I wrote autochapter with Codex CLI in one shot, and it's a great example of a project I would have never bothered building if it weren't for a coding agent to do the gruntwork for me. That makes autochapter Certified Shovelware.