## Summary
Addresses all 8 issues from the QA report to improve agent and user experience.
### P0 — Must Fix
- **Blank template broken captions**: Removed `compositions/captions.html` and its reference from the blank template. Every agent (10/10) hit 404 errors during render.
- **Inner-wrapper example**: Added a clear structural comment in the blank template showing the correct `class="clip"` + inner wrapper pattern.
- **Sub-composition introspection**: `hyperframes compositions` now reads external HTML files referenced via `data-composition-src` and shows their real duration/element count instead of `0.0s / 0 elements`.
### P1 — Fix Soon
- **Font mapping warnings**: Now lists all mapped fonts, suggests alternatives (use a mapped font, add @font-face, install locally), and links to docs.
- **Browser 404s**: Non-font "Failed to load resource" 404s now prefixed with `[non-blocking]` instead of `[Browser:ERROR]`.
- **Render concurrency**: Default workers increased from `cores/2` (max 4) to `cores*3/4` (max 6). Added `--concurrency` alias.
### P2 — Nice to Have
- **Transform conflict fix suggestion**: `gsap_css_transform_conflict` now suggests exact GSAP property replacements (e.g., `xPercent: -50, yPercent: -50`).
- **Upgrade --yes**: Now actually runs the install instead of just printing the command.
## Before / After
### Font mapping warning
**Before:**
```
[Compiler] No deterministic font mapping for: DM Sans
```
**After:**
```
[Compiler] No deterministic font mapping for: DM Sans
Mapped fonts: arial → inter, courier → jetbrains-mono, ...
To fix, pick one:
1. Use a mapped font name instead (see list above)
2. Add a @font-face block in your HTML with a local or hosted font file
3. Install the font locally on the render machine (Docker: add to Dockerfile)
4. Add an alias to FONT_ALIASES in deterministicFonts.ts (for contributors)
```
### Browser 404s during render
**Before:** `[Browser:ERROR] Failed to load resource: the server responded with a status of 404`
**After:** `[non-blocking] Failed to load resource: the server responded with a status of 404`
### Transform conflict lint
**Before:** `Fix: Remove the transform from CSS and use tl.fromTo...`
**After:** `Fix: Remove transform: translate(-50%, -50%) from CSS and replace with GSAP properties: xPercent: -50, yPercent: -50`
### Compositions command
**Before:**
```
overlay 0.0s 1920×1080 0 elements
```
**After:**
```
overlay 8.0s 1920×1080 2 elements ← compositions/overlay.html
```
## Test plan
- [x] All 422 core tests pass
- [x] TypeScript compiles cleanly (all 4 packages)
- [x] Full monorepo build succeeds
- [x] `hyperframes init --template blank` ships without broken captions reference
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 preview # preview in browser (live reload)
npx hyperframes render # render to MP4
Requirements: Node.js >= 22, FFmpeg
Documentation
Full documentation at hyperframes.heygen.com — start with the Quickstart, then explore guides, concepts, API reference, and package docs.
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.
Contributing
See CONTRIBUTING.md for guidelines on how to contribute.
License
See LICENSE for details.