Miguel Ángel
1e05d78378
## Summary
- **Enable browser pool by default** (`enableBrowserPool: true`) — parallel capture workers now share a single Chrome process via reference-counted pool instead of each spawning their own (~256MB each). A 6-worker render drops from 7+ browser parent processes to 1 shared pool.
- **Add launch-promise deduplication** in `acquireBrowser` — when multiple workers race into the pool simultaneously (via `Promise.all`), they await the same launch Promise instead of each triggering a separate Chrome spawn. Same pattern as the existing `_autoBrowserGpuModeCache` for GPU probes.
- **Add `connected` health check** on pool hit — if Chrome crashes mid-render, subsequent acquires detect the dead browser and launch fresh instead of returning a stale reference.
- **Add `drainBrowserPool()`** for explicit cleanup between independent render jobs.
- **CLI studio server** now uses the shared pool instead of its own redundant `enableBrowserPool: false` singleton, so thumbnail generation shares Chrome with render workers.
## Problem
The engine had a reference-counted browser pool (`browserManager.ts:73-75`) but it was **disabled by default** (`enableBrowserPool: false`). This meant:
1. **Every parallel worker spawned its own Chrome** — a `--workers 6` render launched 7+ independent Chrome processes (1 probe + 6 workers), each ~256MB.
2. **The pool had a race condition** — even if manually enabled, concurrent workers calling `acquireBrowser()` via `Promise.all` could all see `pooledBrowser === null` before the first launch completed, spawning N Chromes instead of 1.
3. **No crash recovery** — if Chrome died, the pool still held the dead reference. Subsequent acquires got a disconnected browser.
4. **CLI studio server ran its own singleton** — `studioServer.ts` explicitly set `enableBrowserPool: false` and managed a separate browser, so thumbnails and renders could never share.
Over time, orphaned Chrome processes accumulated across renders and previews. We observed **344 headless Chrome processes** consuming **569% CPU and 20% memory** on a dev machine.
## Before / After (6-worker parallel render)
| Metric | Before (pool off) | After (pool on) |
|--------|-------------------|-----------------|
| Browser parent processes | 7+ (1 probe + 6 workers) | **2** (1 GPU probe + 1 shared) |
| Total Chrome processes (with helpers) | 40-50+ | **14** |
| Memory during capture | ~20%+ | **4.6%** |
| Render time (1200 frames, 30fps) | ~64s | **53s** (~17% faster) |
| Post-render orphans | Accumulated over time | **0** |
## Changes
| File | Change |
|------|--------|
| `engine/src/config.ts` | `enableBrowserPool` default `false` → `true` |
| `engine/src/services/browserManager.ts` | Extract `launchBrowser()`, add `_pooledBrowserLaunchPromise` dedup, add `connected` check on pool hit, add `drainBrowserPool()` and `_resetBrowserPoolForTests()` |
| `engine/src/index.ts` | Export `drainBrowserPool` |
| `engine/src/services/browserManager.test.ts` | Pool dedup and drain tests |
| `cli/src/server/studioServer.ts` | Remove `enableBrowserPool: false` override — thumbnails now share the pool |
| `producer/src/services/browserManager.ts` | Re-export `drainBrowserPool` |
## Backward compatibility
- `PRODUCER_ENABLE_BROWSER_POOL=false` env var disables pooling (same as before).
- Callers passing `{ enableBrowserPool: false }` explicitly still get isolated browsers.
- Tests that set `enableBrowserPool: false` in their config fixtures continue to work.
## Test plan
- [x] Engine tests pass (597/597)
- [x] Producer tests pass (406/407, 1 pre-existing flaky test in `pngDecodeBlitWorkerPool`)
- [x] Build passes (lint, format, typecheck all green via lefthook pre-commit)
- [x] Manual render: `shortform-financial` with `--workers 6` → 1200 frames in 53s, 0 orphaned Chrome processes after completion
- [x] Process monitoring during render confirmed 2 browser parents (1 GPU probe + 1 shared pool) instead of 7+
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.
Quick Start
Option 1: With an AI coding agent (recommended)
Install the HyperFrames skills, then describe the video you want:
npx skills add heygen-com/hyperframes
This teaches your agent (Claude Code, Cursor, Gemini CLI, Codex) how to write correct compositions, GSAP timelines, Tailwind v4 browser-runtime styles, and first-party adapter animations. In Claude Code, the skills register as slash commands — invoke /hyperframes to author compositions, /hyperframes-cli for the dev-loop commands (init, lint, preview, render), /hyperframes-media for asset preprocessing (TTS, transcription, background removal), /tailwind for init --tailwind projects, /gsap for timeline animation help, or the adapter skills (/animejs, /css-animations, /lottie, /three, /waapi) when a composition uses those runtimes.
For Claude Design, open docs/guides/claude-design-hyperframes.md on GitHub and click the download button (↓) to save it, then attach the file to your Claude Design chat. It produces a valid first draft; refine in any AI coding agent. See the Claude Design guide.
For Codex specifically, the same skills are also exposed as an OpenAI Codex plugin — sparse-install just the plugin surface:
codex plugin marketplace add heygen-com/hyperframes --sparse .codex-plugin --sparse skills --sparse assets
For Claude Code, the repo also ships a Claude Code plugin manifest: test it locally with claude --plugin-dir .. The manifest intentionally omits skills because Claude Code auto-discovers the root skills/ directory by convention, and for marketplace submission use the title HyperFrames by HeyGen plus the black/white icon assets at assets/claude-code-icon-dark.svg and assets/claude-code-icon-light.svg for the two theme slots.
For Cursor, the same skills are packaged as a Cursor plugin — install from the Cursor Marketplace, or sideload by cloning this repo and pointing Settings → Plugins → Load unpacked at the repo root.
Try it: example prompts
Copy any of these into your agent to get started. The /hyperframes prefix loads the skill context explicitly so you get correct output the first time.
Cold start — describe what you want:
Using
/hyperframes, create a 10-second product intro with a fade-in title, a background video, and background music.
Warm start — turn existing context into a video:
Take a look at this GitHub repo https://github.com/heygen-com/hyperframes and explain its uses and architecture to me using
/hyperframes.
Summarize the attached PDF into a 45-second pitch video using
/hyperframes.
Turn this CSV into an animated bar chart race using
/hyperframes.
Format-specific:
Make a 9:16 TikTok-style hook video about [topic] using
/hyperframes, with bouncy captions synced to a TTS narration.
Iterate — talk to the agent like a video editor:
Make the title 2x bigger, swap to dark mode, and add a fade-out at the end.
Add a lower third at 0:03 with my name and title.
The agent handles scaffolding, animation, and rendering. See the prompting guide for more patterns.
Option 2: Start a project manually
npx hyperframes init my-video
cd my-video
npx hyperframes preview # preview in browser (live reload)
npx hyperframes render # render to MP4
hyperframes init installs skills automatically, so you can hand off to your AI agent at any point.
Requirements: Node.js >= 22, FFmpeg
Why Hyperframes?
- HTML-native — compositions are HTML files with data attributes. No React, no proprietary DSL.
- AI-first — agents already speak HTML. The CLI is non-interactive by default, designed for agent-driven workflows.
- Deterministic rendering — same input = identical output. Built for automated pipelines.
- Frame Adapter pattern — bring your own animation runtime (GSAP, Lottie, CSS, Three.js).
Hyperframes vs Remotion
Hyperframes is inspired by Remotion — we used Remotion at HeyGen in production, learned a ton from it, and kept attribution comments in the source for the patterns it pioneered (Chrome launch flags, image2pipe → FFmpeg streaming, frame buffering). Both tools drive headless Chrome and both are deterministic. They differ on one decision: what the primary author writes. Remotion's bet is React components; Hyperframes' bet is HTML.
| Hyperframes | Remotion | |
|---|---|---|
| Authoring | HTML + CSS + GSAP | React components (TSX) |
| Build step | None; index.html plays as-is |
Required (bundler) |
| Library-clock animations (GSAP, Anime.js, Motion One) | Seekable, frame-accurate | Plays at wall-clock during render |
| Arbitrary HTML / CSS passthrough | Paste and animate | Rewrite as JSX |
| Distributed rendering | Single-machine today | Lambda, production-ready |
Licensing: fully open source vs source-available
Hyperframes is completely open source under Apache 2.0 — an OSI-approved license. Use it commercially at any scale, with no per-render fees, no seat caps, no company-size thresholds.
Remotion is source-available, not open source. The code is on GitHub under a custom Remotion License that requires a paid company license above small-team thresholds. It's a great product with a real team behind it — but if open-source licensing matters to you (OSI compliance, redistribution rights, no per-use fees), that's a first-order decision point.
Full write-up with benchmarks, an honest list of where each tool wins, and a GSAP side-by-side: Hyperframes vs Remotion guide.
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-index="0"
src="intro.mp4"
muted
playsinline
></video>
<img
id="overlay"
class="clip"
data-start="2"
data-duration="3"
data-track-index="1"
src="logo.png"
/>
<audio
id="bg-music"
data-start="0"
data-duration="9"
data-track-index="2"
data-volume="0.5"
src="music.wav"
></audio>
</div>
Preview instantly in the browser. Render to MP4 locally or in Docker.
Catalog
50+ ready-to-use blocks and components — social overlays, shader transitions, data visualizations, and cinematic effects:
npx hyperframes add flash-through-white # shader transition
npx hyperframes add instagram-follow # social overlay
npx hyperframes add data-chart # animated chart
Browse the full catalog at hyperframes.heygen.com/catalog.
Documentation
Full documentation at hyperframes.heygen.com/introduction — Quickstart | Guides | API Reference | Catalog
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 |
@hyperframes/player |
Embeddable <hyperframes-player> web component |
@hyperframes/shader-transitions |
WebGL shader transitions for compositions |
Skills
HyperFrames ships skills that teach AI agents framework-specific patterns that generic docs don't cover.
npx skills add heygen-com/hyperframes
| Skill | What it teaches |
|---|---|
hyperframes |
HTML composition authoring, captions, TTS, audio-reactive animation, transitions |
hyperframes-cli |
Dev-loop CLI: init, lint, inspect, preview, render, doctor |
hyperframes-media |
Asset preprocessing: tts (Kokoro), transcribe (Whisper), remove-background (u2net) — voice/model/codec selection |
hyperframes-registry |
Block and component installation via hyperframes add |
website-to-hyperframes |
Capture a URL and turn it into a video — full website-to-video pipeline |
remotion-to-hyperframes |
Translate a Remotion (React) composition into a HyperFrames HTML composition |
gsap |
GSAP timelines for HyperFrames: paused registration, deterministic seeking, easing, sequencing, performance |
animejs |
Anime.js animations and timelines registered on window.__hfAnime for deterministic HyperFrames seeking |
css-animations |
CSS keyframe animation patterns that HyperFrames can discover, pause, and seek |
lottie |
lottie-web and dotLottie players registered on window.__hfLottie with local assets and paused playback |
three |
Three.js scenes that render from HyperFrames hf-seek events and window.__hfThreeTime instead of wall-clock time |
waapi |
Web Animations API element.animate() patterns seeked through document.getAnimations() |
Contributing
See CONTRIBUTING.md for guidelines.
Cloning the repo
The repo uses Git LFS for golden regression-test baselines under packages/producer/tests/**/output.mp4 (~240 MB of .mp4 files). If you're cloning the full repo for development, install Git LFS first:
# macOS
brew install git-lfs
# Ubuntu/Debian
sudo apt install git-lfs
# Windows
winget install GitHub.GitLFS
# (or install Git for Windows, which bundles Git LFS as an optional component)
# Then (once, per machine)
git lfs install
If you hit git-lfs filter-process: command not found during git clone or npx skills add heygen-com/hyperframes, install Git LFS and retry. You can also skip LFS content if you only need the source files:
GIT_LFS_SKIP_SMUDGE=1 git clone https://github.com/heygen-com/hyperframes.git