---
name: orbit-chapters
description: Build editable chapter interstitials with calm typography and a travelling perimeter light using HTML, GSAP and HyperFrames.
version: 1.2.2
category: video
delivery: download-only
---

# Orbit Chapters

Use this parameterized renderer for a chapter break, a research milestone or a named phase. Its visual event is a small illuminated stroke completing one trip around an anchored panel while the heading remains readable.

Read [the directing notes](references/directing.md) and [the input contract](references/input.md). Author the subject and language from the brief. A local photograph or sufficiently long video is required as the defocused depth plane; obtain permission to use it and record its provenance in the project. Avoid identifiable faces unless the brief calls for them. Images and finished films stay in projects outside this Skill.

1. Write a JSON brief containing `series`, `marker`, `headline`, `deck`, `footnote`, `palette` and `plate`.
2. Run `node scripts/compose.mjs --brief /absolute/brief.json --dest /absolute/project`.
3. Inspect `index.html`, `brief.json`, `build.json` and `audio-timeline.json` in that project. Change content in the input and regenerate; the HTML and GSAP remain editable for custom direction.
4. Run `node scripts/render.mjs /absolute/project`. This calls pinned HyperFrames 0.8.30, synthesizes separate music and action stems, mixes them into `film.mp4`, and exports `picture.mp4` and `poster.jpg`.
5. Probe and decode both films. Review the entry, corner passages, final hold, random timeline seeks, text bounds and normal speed playback. Listen before describing the sound as accepted.

Requirements: Node.js 20+, npm, Python 3 and FFmpeg/ffprobe. HyperFrames requires a supported local Chromium installation and permission to run its rendering subprocesses. First use of `npx` requires network access; GSAP and fonts are installed into an external cache from fixed upstream versions, with SHA256 verification. Use `node scripts/install-runtime.mjs` for a cold install. `ORBIT_RUNTIME_OFFLINE=1` prohibits network requests; `ORBIT_RUNTIME_CACHE` chooses a cache outside the Skill folder. No API key or paid generation is required. A rendering permission failure must be reported with its actual error; HTML generation alone is not a completed film.

The supplied audio is deterministic procedural synthesis, not a sampled commercial song or a voiceover. Its timing is editable in `audio-timeline.json`; `music.wav`, `actions.wav` and `mix.wav` expose the actual stems. Sound is optional: distribute `picture.mp4` when a silent interstitial is wanted. Music quality and actual listening are separate from stream and level measurements.

This is a constrained single-panel renderer, not an automatic film director. The title and palette are parameterized; a new scene structure requires HTML/GSAP authoring. The generic package carries no third-party binary files. Required notices travel with installed assets into the cache and editable projects. Do not strip them from those installed files.

Video depth plates must contain at least 7.6 continuous seconds. Their stable timeline identity is preserved for HyperFrames media sampling and editing.