| name | transcribe-video |
| description | Use when the user wants to transcribe a video or audio file to text with word-level timestamps — spins up a self-contained local Whisper (whisper.cpp) Docker service bundled in this skill and returns transcript.txt, transcript.srt, and word-level transcript.words.json. Also used as a building block by /produce-video. Triggers on "transcribe this video", "get a transcript", "transcribe-video". |
Transcribe Video
Transcribes any video/audio file locally using a bundled whisper.cpp service. No external project or cloud API. Returns word-level timestamps (needed for synced overlays/captions).
When to use
- "Transcribe this clip / video / audio", "get me a transcript with timestamps".
- As a sub-step of
/produce-video.
How it runs
Everything is driven by the bundled runner — never ask the user to manage Docker:
node scripts/transcribe.mjs <path-to-video-or-audio> [--out <dir>] [--port 9111] [--language en] [--no-word-ts] [--task transcribe|translate]
node scripts/transcribe.mjs --stop
The runner:
- Checks the Docker daemon is reachable (fails loud with guidance if not).
- Builds the
transcribe-video-whisper image from assets/whisper-service/ if it is missing (first build is slow: it compiles whisper.cpp and bakes the ggml-base.en.bin model).
- Starts the
transcribe-video-whisper container (host port 9111 → container 9001); reuses it if already running, docker starts it if stopped.
- Waits for
GET /healthz to report ok.
- Extracts a 16 kHz mono WAV from the input with local ffmpeg (whisper.cpp only decodes WAV), then POSTs it to
/transcribe with word_ts=true.
- Writes
transcript.txt, transcript.srt, transcript.words.json to --out (default: the input file's directory), and prints a JSON result line to stdout.
Outputs
transcript.txt — plain text.transcript.srt — subtitle text.transcript.words.json — [{ "word", "start", "end" }], seconds, time-ordered. This is the sync source for overlays/captions.
stdout result line (for programmatic callers like /produce-video):
{ "ok": true, "outDir": "...", "wordCount": 38, "segmentCount": 2, "files": { "txt": "transcript.txt", "srt": "transcript.srt", "words": "transcript.words.json" } }
Requirements
- Docker is REQUIRED — the Whisper service runs in a container, so Docker Desktop must be installed AND running. The runner checks this first and fails loud with install/start guidance if Docker is missing or its daemon is down; there is no non-Docker fallback.
- ffmpeg is REQUIRED (used to extract a 16 kHz mono WAV for Whisper) — the runner checks for it up front and fails loud if it is not on PATH.
- Node ≥ 22.
Notes
- The container is left running (
--restart unless-stopped) for warm reuse; stop with --stop.
- If word timestamps are requested but none come back, the runner fails loud (overlay sync depends on them).
- See
references/ for the Docker lifecycle, the API shape, and the vendoring provenance.
