heygen-com--hyperframes/packages/engine/README.md

@hyperframes/engine

Seekable web-page-to-video rendering engine built on Puppeteer and FFmpeg.

Framework-agnostic: works with GSAP, Lottie, Three.js, CSS animations, or any web content that implements the window.__hf seek protocol.

Install

npm install @hyperframes/engine

Requirements: Node.js >= 22, Chrome/Chromium (auto-downloaded by Puppeteer), FFmpeg

What it does

The engine opens your HTML composition in a headless Chrome instance, seeks frame-by-frame using Chrome's HeadlessExperimental.beginFrame API, captures screenshots, and encodes them into video with FFmpeg.

Key services

Service	Description
browserManager	Launches and pools headless Chrome instances (chrome-headless-shell)
frameCapture	Manages capture sessions — seek, screenshot, buffer lifecycle
screenshotService	BeginFrame-based capture with CDP (Chrome DevTools Protocol)
chunkEncoder	FFmpeg encoding with chunked concat, GPU detection, faststart
streamingEncoder	Pipe frames to FFmpeg in real time (no intermediate PNGs on disk)
audioMixer	Parse <audio> elements and mix audio tracks via FFmpeg
videoFrameExtractor	Extract frames from <video> elements for compositing
parallelCoordinator	Split frame ranges across worker processes
fileServer	Serve local HTML files to the browser via Hono

Usage

import {
  acquireBrowser,
  releaseBrowser,
  createCaptureSession,
  initializeSession,
  captureFrame,
  closeCaptureSession,
} from "@hyperframes/engine";

// 1. Launch browser
const browser = await acquireBrowser({ captureMode: "beginFrame" });

// 2. Open a capture session
const session = createCaptureSession({
  browser: browser.browser,
  url: "http://localhost:3000/my-composition.html",
  width: 1920,
  height: 1080,
  fps: 30,
});
await initializeSession(session);

// 3. Capture frames
for (let i = 0; i < totalFrames; i++) {
  await captureFrame(session, i, `/tmp/frames/frame-${i}.png`);
}

// 4. Clean up
await closeCaptureSession(session);
await releaseBrowser(browser);

Most users should use @hyperframes/producer or the hyperframes CLI instead of calling the engine directly.

Documentation

Full documentation: hyperframes.heygen.com/packages/engine

Related packages

• @hyperframes/core — types, parsers, frame adapters
• @hyperframes/producer — high-level render pipeline built on this engine
• hyperframes — CLI