Files
Vance Ingalls b3c7f8fb64 docs(hdr-regression): document maxFrameFailures budget rationale
Address jrusso1020's nit on PR #365 (non-blocking review): both READMEs now
explain where the tolerance values come from.

- hdr-regression/README.md: add a budget-breakdown table that derives the 30
  frames from the deltas in PRs #369 (window C fix → 5) and #375 (window F
  fix → 0). The table doubles as a contract: if a future change forces the
  budget back up, exactly one bucket has regressed and the table tells you
  which one to investigate first.
- hdr-hlg-regression/README.md: add a 'Tolerance' section explaining why 0
  is the right floor (HLG is a pure pass-through path, HEVC over rgb48le is
  byte-deterministic on the same fixture, so any drift is a real regression).

The regeneration command for generate-hdr-photo-pq.py was already documented
at README lines 67-71, so no changes needed there.
2026-04-22 23:07:20 -07:00
..
2026-04-23 01:13:37 -04:00
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,
  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