| name | audio-track |
| description | Use when the user wants music, voiceover, narration, or a soundtrack added to a video asset, OR wants standalone generated audio for any purpose (e.g. "/audio-track", "add music to the launch video", "narrate the demo", "make a 30 second music sting", "generate a voiceover mp3", "jingle for the intro"). |
Audio Track
REQUIRED BACKGROUND: marketing-studio skill. Work in C:\Projects\animations.
Read the PLAYBOOK's Audio section first (endpoints, ducking, manifest contract).
Two modes; pick by what the user wants:
- Video soundtrack — the target composition re-rendered with music + voiceover
(
out/<brand>/<asset>-audio.mp4). Recipe A.
- Standalone audio — a music track and/or narration mp3s delivered as files
(a sting, a jingle, a narration for something outside this studio). Recipe B.
Both need ELEVENLABS_API_KEY in the repo .env (missing key = feeder exits 2;
videos stay silent). Generation costs real money: one pass, trim copy rather than
regenerate blindly. Free tier returns 402; Starter or above required.
Recipe A: video soundtrack
- Shared-repo guard + toolchain per marketing-studio.
- Copy source of truth:
scripts/build-<brand>-audio.mjs (copy the noban one for a
new brand). VO lines are keyed by act, written FOR THE EAR ("dot gg", not ".gg"),
one line per act, terse. Music prompt describes the brand's sonic character.
- Run it:
node scripts/build-<brand>-audio.mjs (music takes 1-3 min). Check every
line's duration fits its act; trim TEXT if not, re-run with --force.
- Merge + render:
node scripts/merge-launch-audio.mjs then render the composition
with the merged props.
- Listen-proof: verify the mp4 has an audio stream (ffprobe), then SEND the video —
audio is approved by ear, by the user. Ducking feel (base 0.35 / duck 0.12) is
tunable in
studio/src/lib/audioMix.ts if redlined.
Recipe B: standalone audio
- Shared-repo guard per marketing-studio (the feeder lives in the engine repo even
for standalone output).
- Music:
node feeders/audio/client.mjs music --prompt "<sonic character>" --length-ms <n> --out out/<brand>/<name>.mp3
(exact-length, commercially licensed on paid plans; 3s-120s).
Voiceover: write {lines: [{id, text}]} to a temp JSON (text written for the ear),
then node feeders/audio/client.mjs vo --script <json> --out out/<brand>/.
Durations print as ... OK: <name> <ms>ms; probe --file <mp3> re-measures.
- Listen-proof: SEND the mp3(s) to the user, then copy approved files into the
calling repo per the marketing-studio delivery contract.
