Motion video

Make a 1920×1080 30 fps motion-graphic video where the scene cuts land on the music's beats, reveals land on spoken words, and the audio is broadcast-clean. The workflow is fully scripted: facts → script → multix audio → forced alignment → beat grid → bar-spliced music → timeline + mix → HTML composition → lint/check/snapshot → render → remux → social encode.

Two finished editions show what each style should feel like. Their working projects are deliberately not bundled here: the generated voice-over, music and SFX are large and provider-licensed. Study the published demo, then build every new video from assets/templates/index-skeleton.html plus the style reference.

Scope

This skill handles:

• New videos in either style, restyles of an existing video as a separate project,

and partial reworks (new music, re-timed drops, re-mix, re-render, social encode).

• Audio through the multix CLI: Gemini TTS voice, ElevenLabs SFX, ElevenLabs

Music composition plans, ElevenLabs forced alignment.

This skill does NOT handle:

• Generative text-to-video footage (use multix Seedance/Veo directly).
• React/Remotion compositions or generic HyperFrames questions (use the

hyperframes or remotion skills).

• Publishing to social accounts: produce the file and let the user post it.

How to work

1. Pin the outcome before touching files: topic and sources, style (one of the two, or a new one derived from them), duration, voice language (English VO + Vietnamese captions by default), ending, signature. Ask only if the style or the facts source is unknown. 2. Create assets/videos/<slug>/ (never overwrite a finished edition) and a plan under plans/ following the repo convention. Copy the templates from assets/templates/ of this skill: scripts/*.mjs, data/*.example.json (rename to .json), hyperframes.json, index-skeleton.html as index.html, plus scripts/fit-beat-grid.py. 3. Follow references/production-pipeline.md step by step. Each step writes a file the next one reads, so do not reorder them. 4. Get the music right with references/audio-and-beat-sync.md: fit the grid, splice bars so the drops land where the script needs them, verify the splice, and measure the voice/music balance. 5. Build index.html with references/composition-contract.md and the chosen style reference, starting from assets/templates/index-skeleton.html. When a scene type repeats (stats, diagrams, charts, terminal, graph, outro), follow the demo's choreography for that scene instead of inventing a new one. 6. Finish only when every check in "Done when" passes; report measured numbers, not impressions.

Keep credentials inside multix's own config. Never print API keys or copy them into project files, plans or reports.

Done when

• hyperframes lint and check pass; snapshots of every scene were reviewed.
• verify-arrangement.py reports every segment within ±2 ms and

measure-mix-balance.py shows the music ~4–6 dB under speech.

• ffprobe: 1920×1080, 30 fps, expected duration, AAC 48 kHz stereo;

ebur128 ≈ −14 LUFS with peak ≤ −1 dBFS; blackdetect finds nothing outside fades.

• build-timeline printed no clip/overlap/missing-word warnings.
• On-screen facts trace to the sources collected in step 1.

Resources

• references/production-pipeline.md: every command from scaffold to social

encode and studio preview, plus the rebuild table.

• references/audio-and-beat-sync.md: voice, SFX cues, music plans,

bar-splice arrangement, anchors, mix numbers and the ducking pitfall.

• references/composition-contract.md: TIMING shape, helpers, determinism,

scene windows, captions, mascot, renderer limits, signature.

• references/style-glass-keynote.md / references/style-comic-spiderverse.md:

tokens, fonts, layers, components, transitions and caption look per style.

• scripts/fit-beat-grid.py <music> [--min-bpm N --max-bpm N]: BPM, BEAT0 and a

per-bar kick/energy table.

• scripts/verify-arrangement.py <project> [--tolerance-ms 2]: splice lag per

segment; exits 1 on drift.

• scripts/measure-mix-balance.py <project>: music under speech vs in gaps,

from build-timeline.mjs --stems.

• scripts/tests/: python -m unittest discover -s scripts/tests (needs

ffmpeg, numpy, scipy).

• assets/templates/: project scripts (generate-audio-assets,

align-voiceover, arrange-music, build-timeline), example data files and the composition skeleton.