## Summary - **Lint rules** catch media elements missing `id` (renderer silently skips them), missing `src`, `preload="none"` (blocks renderer), and video nested in timed divs (freezes playback). Upgraded `video_nested_in_timed_element` from warning to error. - **Compiler** strips `preload="none"` from media during compilation. Runs parallel, cached keyframe interval analysis via ffprobe — warns on sparse keyframes (>2s) that cause seek failures and audio/video desync. Suggested ffmpeg command preserves audio (`-c:a copy`). - **Pre-render lint** lints `index.html` + all `compositions/*.html` sub-compositions before render via shared `lintProject()` helper. Warns by default; `--strict` blocks on errors, `--strict-all` blocks on errors + warnings. - **Render orchestrator** logs a hint to retry with `--workers 1` when parallel capture times out on video-heavy compositions. - **Refactor**: extracted `runFfprobe()` + `parseProbeJson()` helpers to deduplicate ~80 lines of spawn boilerplate across 3 ffprobe functions. Extracted `shouldBlockRender()` so strict flag tests exercise production code. Shared `lintProject()` used by both `lint` and `render` commands. ## Context Discovered during a real composition build session where: 1. `<audio>` without `id` rendered silently (preview worked fine because runtime queries `[data-start]`, but renderer queries `[id][src]`) 2. `<video>` inside timed `<div>` froze on first frame 3. `preload="none"` caused 45s renderer timeout 4. YouTube clips with sparse keyframes from `yt-dlp --download-sections` caused audio/video desync 5. Parallel workers timed out on video-heavy compositions ## Test plan - [x] Core: 365/365 tests passing (5 new lint tests) - [x] Engine: 24/24 tests passing - [x] CLI: 14/14 tests passing (7 lintProject + 7 shouldBlockRender) - [x] Lint + format hooks pass - [ ] Manual: create a composition with `<audio data-start="0" src="test.wav">` (no id) — verify `npx hyperframes lint` catches it - [ ] Manual: run `npx hyperframes render --strict` with lint errors — verify it blocks - [ ] Manual: run `npx hyperframes render --strict-all` with lint warnings — verify it blocks
Hyperframes
Write HTML. Render video. Built for agents.
Hyperframes is an open-source video rendering framework that lets you create, preview, and render HTML-based video compositions — with first-class support for AI agents via MCP.
Why Hyperframes?
- HTML-native — AI agents already speak HTML. No React required.
- Frame Adapter pattern — bring your own animation runtime (GSAP, Lottie, CSS, Three.js).
- Deterministic rendering — same input = identical output. Built for automated pipelines.
- AI-first design — not a bolted-on afterthought.
Quick Start
npx hyperframes init my-video
cd my-video
Then open the project with your AI coding agent (Claude Code, Cursor, etc.) — it has HyperFrames skills installed and knows how to create and edit compositions.
npx hyperframes dev # preview in browser (live reload)
npx hyperframes render # render to MP4
Requirements: Node.js >= 22, FFmpeg
How It Works
Define your video as HTML with data attributes:
<div id="stage" data-composition-id="my-video" data-start="0" data-width="1920" data-height="1080">
<video
id="clip-1"
data-start="0"
data-duration="5"
data-track="0"
src="intro.mp4"
muted
playsinline
></video>
<img id="overlay" data-start="2" data-duration="3" data-track="1" src="logo.png" />
<audio
id="bg-music"
data-start="0"
data-duration="9"
data-track="2"
data-volume="0.5"
src="music.wav"
></audio>
</div>
Preview instantly in the browser. Render to MP4 locally. Let AI agents compose videos using tools they already understand.
Packages
| Package | Description |
|---|---|
hyperframes |
CLI — create, preview, lint, and render compositions |
@hyperframes/core |
Types, parsers, generators, linter, runtime, frame adapters |
@hyperframes/engine |
Seekable page-to-video capture engine (Puppeteer + FFmpeg) |
@hyperframes/producer |
Full rendering pipeline (capture + encode + audio mix) |
@hyperframes/studio |
Browser-based composition editor UI |
AI Agent Skills
HyperFrames ships skills that teach AI coding agents (Claude Code, Gemini CLI, Codex, Cursor) how to write correct compositions and GSAP animations. Use these instead of writing from scratch — they encode framework-specific patterns that generic docs don't cover.
Install via CLI (recommended)
# Install all skills (HyperFrames + GSAP) — runs automatically during `hyperframes init`
npx hyperframes skills
# Or install to a specific agent
npx hyperframes skills --claude
npx hyperframes skills --cursor
Or via npx skills add
# HyperFrames skills (hyperframes-compose, hyperframes-captions)
npx skills add heygen-com/hyperframes
# GSAP skills (gsap-core, gsap-timeline, gsap-scrolltrigger, gsap-plugins, gsap-performance, gsap-utils, gsap-react, gsap-frameworks)
npx skills add greensock/gsap-skills
Installed Skills
| Source | Skills | What they teach |
|---|---|---|
| HyperFrames | hyperframes-compose, hyperframes-captions |
HTML composition structure, class="clip" rules, data-* attributes, timeline registration, rendering constraints |
| GSAP | gsap-core, gsap-timeline, gsap-performance, gsap-plugins, gsap-scrolltrigger, gsap-utils, gsap-react, gsap-frameworks |
Core API, timeline sequencing, ScrollTrigger, plugin usage, performance best practices |
In Claude Code, invoke with /hyperframes-compose, /hyperframes-captions, /gsap-core, etc.
Documentation
Full docs at hyperframes.heygen.com — includes guides, concepts, API reference, and package documentation.
Contributing
See CONTRIBUTING.md for guidelines on how to contribute.
License
See LICENSE for details.