chapterize

Load audio and subtitle files into the Chapterize Mac app from the command line. Point it at an episode (with optional SRT or VTT subtitles) and it appears in Chapterize as a new document, ready for chapter editing.

Pairs well with quicksubs: transcribe an episode, then hand the audio and transcript straight to Chapterize.

Install

brew install mattbirchler/tap/chapterize

Requires macOS 26 (Tahoe) or later, and Chapterize 1.6 or later.

Usage

chapterize episode.mp3                 # load into the app, then open it
chapterize ep.mp3 -s ep.srt            # load with a specific subtitle file
chapterize a.mp3 b.mp3                 # load two documents at once
chapterize ep.mp3 --show "Cozy Zone"   # associate with a show by name
chapterize ep.mp3 --no-open            # stage without opening the app
chapterize --open                      # just open the app
chapterize ep.mp3 --json -q            # silent run, JSON result on stdout

Use --show to associate the file with a show by name (no IDs). If a show with that name already exists in Chapterize, the file is loaded pre-associated with it (name and artwork); if not, the name is still applied as the episode's show label. The name applies to every file in the command.

Audio can be mp3, m4a, mp4, m4b, wav, wave, aif, or aiff (non-MP3 formats are converted inside the app, exactly like a drag-and-drop import). A subtitle file sitting next to the audio with the same name (ep.mp3 plus ep.srt or ep.vtt) is picked up automatically; --no-auto-subs turns that off.

Progress goes to stderr and results go to stdout, so it pipes cleanly.

The first run may trigger a macOS prompt asking to allow access to data from other apps. Approve it: the tool works by handing files to Chapterize's inbox. If you denied it, re-enable access in System Settings under Privacy and Security before trying again.

Analytics

Successful runs send one small anonymous event to PostHog (the same project the Chapterize app reports to): the event name, file and subtitle counts, whether a show name was used, the CLI version, and the macOS version. No file names, paths, show names, or other content are ever sent. IP addresses are discarded at ingestion and no location is derived. A random ID stored in ~/Library/Application Support/chapterize/ lets PostHog count distinct users; it identifies nothing but "same machine as last time".

To opt out, set CHAPTERIZE_NO_ANALYTICS=1 (or the cross-tool convention DO_NOT_TRACK=1) in your environment.

Exit codes

Code	Meaning
0	Success
1	Bad input or usage error
2	Handoff failure (Chapterize not installed, staging or open failed)