Short-Form Vertical Video (Hyperframes)

Short-form = 1080x1920 vertical, 10, 30s, talking-head face + motion-graphic scene overlays + karaoke captions. Everything in this skill is distilled from the May Shorts 19 iteration autopsy (v1 → v4) and is preserved for maintenance of those examples. Use short-form-edit for new recordings.

Always invoke /hyperframes first. This skill sits on top of it, it does not replace the framework rules (data-* attributes, window.__timelines, composition structure). Those are non-negotiable regardless of the format.

When this skill fires

• Maintaining the existing May Shorts examples.
• Explicitly requesting their legacy four-layer scaffold.

The playbook (high-level)

1. Audio is source of truth. Edit audio FIRST (cut retakes, pauses). Save as <name>-edit.mp4. Measure exact duration with ffprobe, this is the composition's data-duration.
2. Transcribe the edited audio with the root scripts/transcribe-elevenlabs.mjs helper (ElevenLabs Scribe), a student-selected alternative normalized per docs/TOOLS-AND-API-KEYS.md, or if retiming an existing build with a shift() function in captions, keep the existing captions and just shift scene starts.
3. Author scene boundaries in edited-time, NEVER mix original-time and edited-time anchors in the same file. See "Audio-sync protocol" below.
4. Build the composition scaffold (4 layers: ambient-bg, seam-treatment, captions, face), see "Composition scaffold" below.
5. Author scenes with LOCAL offsets relative to each scene's data-start. Each scene is its own sub-composition under compositions/scene<N>-<label>.html.
6. Lint → draft render → word-exact frame verification → final render. This is the verification gate. Never skip step 3 (frame verification).

Composition scaffold (the 4 always-on layers)

Every short-form vertical has these four sub-compositions under compositions/, loaded on shared tracks: