Files
hyperframes/packages/engine
Santhi PrakashandMiguel Ángel cad7dbed0d fix(engine): warn when a video input declares alpha but decodes opaque (#3771)
* fix(engine): warn when a video input declares alpha but decodes opaque

- Problem: a video input whose alpha_mode=1 tag outlives its alpha plane (a remux drops the BlockAdditional sidecar while keeping the tag) composites as a solid rectangle, and nothing tells the user their file, not the renderer, is the problem (#3220 / #3226).
- Fix: during extraction preflight, when an input declares alpha (hasAlpha) and its codec can carry alpha, sample the decoded alpha plane (up to 3 frames at 8x8 rgba, bounded 30s, ~768-byte ceiling). If uniformly opaque, emit a non-blocking stderr warning naming the file with the re-export remedy. Inconclusive probes stay silent; opaque full-frame backgrounds are legitimate and never fail the render.
- Verification: 8 new unit tests (byte logic + message); engine suite 1483/1487 with 4 pre-existing failures on clean main (missing hdr-regression PNG fixture in this clone); typecheck/lint/format clean; real-fixture checks: lying-tag WebM warns, genuine-alpha WebM stays silent, both agree with ffmpeg alphaextract.

Signed-off-by: Santhi Prakash <b.santhiprakash@gmail.com>

* fix(engine): probe input alpha with the decoder that matches its codec

* style(engine): format the alpha probe test

* fix(engine): keep the alpha probe from failing or racing a render

---------

Signed-off-by: Santhi Prakash <b.santhiprakash@gmail.com>
Co-authored-by: Miguel Ángel <miguel.sierra@heygen.com>
2026-10-02 04:59:16 -07:00
..
2026-10-02 01:32:47 -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