Files
hyperframes/packages/engine
Miguel Ángel b46ebedeae fix(engine): a 29.97 fps camera clip exports smoothly at 30 fps (#5849)
* fix(engine): a 29.97 fps camera clip exports smoothly at 30 fps

Extraction samples each output frame from the last source frame starting at
or before it. Millisecond container ticks move each frame by up to half a
millisecond, while 29.97 fps drifts against 30 fps by 0.033 ms per frame, so
the rounding decided the slot and the export alternated repeats and skips.
Constant-rate frames are now re-spaced on the stream's own frame grid from
the first decoded frame before sampling. The cache schema moves to v8 so
exports stop reusing frames extracted the old way.

* fix(engine): every extraction process snaps frames to one absolute grid

The grid was anchored on each process's first decoded frame, which carries its
own millisecond rounding, so a segment or distributed chunk could place the
29.97 -> 30 repeat elsewhere and skip a frame at its seam. Frames are now
snapped to the stream's own grid in file time (this process's seek plus the
video's lead), the same in every process.
2026-10-18 16:37:20 +00:00
..
2026-10-18 15:53:44 +00:00
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