Files
hyperframes/packages/engine
Vance IngallsandClaude Opus 5 4d563fa752 fix(engine): guard the rounded frame rate and strict-parse rationals
Two paths the previous guards still let through.

Rounding could recreate Infinity after the finite check. `raw * 100`
overflows for a finite-but-huge rate — "1e307", "1e307/1" — so `rounded`
became Infinity and passed the positivity check, reaching exactly the
`-r Infinity` failure the finite guard exists to prevent. The rounded
result is now checked too.

The rational operands still used parseFloat. The plain-number path
switched to Number() so trailing garbage fails the whole string, but the
numerator and denominator did not, so "60fps/1", "60/1fps" and
"30garbage/1garbage" returned valid rates while the contract says
malformed frame rates fail closed. Both operands are now parsed strictly,
and an empty operand ("/", "/1", "30/") is rejected rather than coerced.

Tests: 8 malformed inputs and 3 overflow cases in the direct table.
Reverting either fix fails 5.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-07-31 19:52:17 -07:00
..
2026-07-31 22:36:46 +02:00
2026-03-21 22:43:56 -07:00

@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,
  createCaptureSession,
  initializeSession,
  captureFrame,
  closeCaptureSession,
} from "@hyperframes/engine";

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

// 2. Open a capture session
const session = createCaptureSession({
  browser: browserLease.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 browserLease.release();

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

Documentation

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