Launch film rendered in code

Produces a 30–70 s film (16:9, 1080p60 by default) plus a voiceover cut, an alternate-voice cut, a music-only cut, captions, posters and a contact sheet. A full 1080p60 render with motion blur takes about 2 minutes on 12 workers, so iterate freely.

Prerequisites

Google Chrome, ffmpeg, Node 18+, python3 with Pillow, and uv (for librosa/requests). Keys in the environment, never written into the project: ELEVENLABS_API_KEY (music, voice, sound effects, speech-to-text), optionally GEMINI_API_KEY (images, Lyria music) and OPENAI_API_KEY (images with transparency).

Start

new_film.sh sits next to this file (global install: ~/.claude/skills/launch-film/, project install: ./.claude/skills/launch-film/).

bash <this skill's folder>/new_film.sh <film-dir>     # copies template/, npm install
cd <film-dir> && node scripts/render.mjs stills 1,4,8,12,18 && python3 scripts/sheet.py review/stills review/sheet.jpg 5 400

The template renders a working 20 s film (title → phone with pop-out and tap → end card). Everything is timed from timeline.json, which both src/stage.js and the audio scripts read.

Gates — do not skip

1. Study. References: download the videos the user points to, tile frames with ffmpeg (fps=N,tile=4x4), and write down pacing, type and transitions shot by shot. Product: collect real screens and screen recordings (extract frames with ffmpeg), the brand fonts, colors and icon, and the claims the film may make (only claims the product backs). Check the current UI in code: captures go stale (a rebuilt button, a new flow).
2. Brief. Fill BRIEF.md: logline, three brand colors, headline + accent fonts, one background, beat sheet with a state list per shot, claims. One idea per shot.
3. Score first. Fill audio.json → musicGen (sections in bars), run scripts/gen_music.py (2–3 seeds), then scripts/analyze_music.py. You cannot listen: pick by grid fit and dynamics (quiet intro, lift, peak, drop). Put the measured bpm/firstBeat in timeline.json and place cuts on measured events (bass entry, two-bar swells, the drop). Trim a silent or sparse opening by whole bars (musicStart), lift the rest (introLift).
4. Rig and stills. Build shots in src/stage.js. Render stills at key times, make a contact sheet, score every shot out of 10, fix the three worst problems, repeat until nothing is under 8.
5. Animatic. render.mjs video --fps 30 --scale 0.5, then tile frames around each transition (ffmpeg -ss A -to B -vf "fps=8,scale=480:-2,tile=6x4") and check the hand-offs.
6. Voice. Write lines in audio.json → voice, run scripts/gen_vo.py main alt, then scripts/qa_speech.py. Lines are placed by speech-to-text word timings; anchor the key word to its beat; split one take instead of stitching fragments; no silence longer than ~1.5 s in the first 10 s.
7. Sound and mix. scripts/gen_sfx.py, then scripts/mix_audio.py (per-cue loudness, voices duck the score, −14 LUFS). Check the mix without ears: speech-to-text on the first 15 s, per-second levels, a spectrogram with cue markers.
8. Final. render.mjs video --fps 60 --sub 4 --shutter 0.5 --workers 12, mux each mix, write SRT captions from the measured voice timings, render poster stills, a contact sheet, and a README with sources and open claims.

Rules

Detail and reasons: references/craft.md. Bugs already paid for: references/pitfalls.md (read before writing code). Short version:

• Every value is a pure function of t (closed-form springs from src/lib/motion.js); nothing reads a clock, no CSS transitions, no unseeded randomness.
• Type enters per word (blur 14 → 0 px, rise 28 px, heavy spring) and exits blurring up. One accent phrase per headline, in the accent font and color. Headline position stays the same shot to shot.
• No hard cuts: each shot hands an object or the camera to the next one.
• Real product UI over mock UI; pop real crops out of the screen. Rebuild stale components in HTML from the code.
• The voiceover speaks the headlines in its own words and goes quiet for the product's own sounds.
• Deliver a voiceover cut and a music-only cut; the first seconds must work muted (autoplay).

Commands

node scripts/render.mjs stills 2.5,8,14 [--scale 0.5] [--dir review/x]
node scripts/render.mjs video --fps 30 --scale 0.5 --out out/animatic.mp4
node scripts/render.mjs video --fps 60 --sub 4 --shutter 0.5 --workers 12 --out out/master.mp4
uv run --with requests python3 scripts/gen_music.py [lyria]
uv run --with librosa --with matplotlib python3 scripts/analyze_music.py assets/audio/music/*.mp3
uv run --with requests python3 scripts/gen_vo.py main alt [chorus] [--only id,id]
uv run --with requests python3 scripts/qa_speech.py assets/audio/vo/main
uv run --with requests python3 scripts/gen_sfx.py
python3 scripts/mix_audio.py out/mix_vo.wav --vo main        # no --vo for the music-only mix
ffmpeg -i out/master.mp4 -i out/mix_vo.wav -map 0:v -map 1:a -c:v libx264 -preset slow -crf 17 -pix_fmt yuv420p \
  -c:a aac -b:a 256k -movflags +faststart -shortest out/film.mp4