git:20260904.14d2e37 to git:20260905.41afbd2

1 added, 1 removed. Audit A to A.

---

name: audio-track

- description: Use when the user wants music, voiceover, narration, or standalone audio - e.g. "/audio-track", "add music to the launch video".

+ description: "Create music, voiceover, narration, or standalone audio; /audio-track."

---

# Audio Track

**REQUIRED BACKGROUND:** marketing-studio skill. Work in `C:/Projects/animations`.

Read the PLAYBOOK's Audio section first (endpoints, ducking, manifest contract).

Every film gets this pass; it is not opt-in (CLAUDE.md: a film is not done without

audio, and audio means narration). `node scripts/check-audio.mjs <brand>` is the exit

gate for all three recipes that touch video.

Three modes; pick by what the target is:

- **Bespoke film** (`studio/src/films/<brand>/`, e.g. PostflopFilm) — post-render

scoring with `scripts/build-<brand>-film-audio.mjs` + `scripts/score-film.mjs`.

Recipe A0.

- **Video soundtrack** — a LaunchVideo template 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 A0: bespoke film

1. Shared-repo guard + toolchain per marketing-studio.

2. Copy source of truth: `scripts/build-<brand>-film-audio.mjs` (copy postflop's).

Narration lines carry the film SECOND they start on, computed from the film's

timeline.ts so a re-timed shot moves its line with it; SFX cues carry the frame the

shot lands something on (Stamp/Rule/click constants + the shot's `from`), max two

per beat. Budget ~2.6 words/second minus a 150ms breath per line.

3. Run it (VO lines and the exact-length bed hit the API once; re-runs reuse files,

`--force <id,...|music>` regenerates). Read the printed start/end table: every line

inside its shot.

4. `node scripts/score-film.mjs <brand> out/<brand>/film/film-vN.mp4` — refuses

overlapping lines (trim copy, re-run the builder) and zero-VO manifests; masters by

measured gain and verifies the DELIVERED file (I within 0.5 of TARGET_I, TP <= -1).

5. Listen-proof: `node scripts/verify-cue.mjs <scored.mp4> <voStart> <voDur>` on one

narration window and one bed-only window (voice ~6 dB above the bed), then

`node scripts/check-audio.mjs <brand>` (exit 0), then SEND the scored file.

## Recipe A: video soundtrack

1. Shared-repo guard + toolchain per marketing-studio.

2. 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.

3. 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.

4. Merge + render: `node scripts/merge-launch-audio.mjs` then render the composition

with the merged props.

5. 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

1. Shared-repo guard per marketing-studio (the feeder lives in the engine repo even

for standalone output).

2. 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.

3. Listen-proof: SEND the mp3(s) to the user, then copy approved files into the

calling repo per the marketing-studio delivery contract.