Files
hyperframes/packages/engine
Youssef Toufik fe017b48c7 feat(producer): true alpha output for webm, mov, and png-sequence
Extends RenderConfig.format with "png-sequence" and patches two correctness
gaps so the existing "webm" / "mov" values actually preserve the alpha
channel end-to-end.

Engine fixes:
- screenshotService.pageScreenshotCapture: drop optimizeForSpeed for PNG
  captures. The fast path uses an alpha-unaware codec that crushes real
  alpha values; kept for opaque jpeg captures where it is harmless.
- frameCapture: replace the inline setDefaultBackgroundColorOverride
  block (which fired pre-navigation and was reset by page.goto) with a
  proper initTransparentBackground() call inside initializeSession,
  after the window.__hf readiness poll. This also injects the
  html/body/[data-composition-id]{background:transparent !important}
  stylesheet so compositions with custom body / #root backgrounds do not
  defeat the override. Wired into both screenshot-mode and beginframe-mode
  branches.

Producer:
- RenderConfig.format extended to "mp4" | "webm" | "mov" | "png-sequence"
  with full JSDoc.
- Streaming encode is bypassed for png-sequence (frames go straight to
  disk). FORMAT_EXT extended.
- New Stage-5 png-sequence branch: mkdir outputPath, copy captured PNGs as
  frame_NNNNNN.png, copy audio.aac sidecar when audio is present.
- Stage-6 mux/faststart and the debug copy are wrapped in !isPngSequence.
- README.md: new "Transparent Video Output" section.

Tests:
- New fixture tests/transparency-regression/ tagged "transparency".
- New tsx script src/transparency-test.ts asserts pixel-level alpha for
  webm + png-sequence outputs. Wired as "test:transparency".
- Default "test" / "test:update" scripts pass --exclude-tags transparency
  so the golden-MP4 harness ignores the new fixture.

Verified locally on macOS arm64: typecheck clean across engine + producer,
producer renderOrchestrator vitest 10/10, transparency-test passes for
both webm and png-sequence with end-to-end pixel assertions.
2026-04-27 20:33:45 +01:00
..
2026-04-26 19:41:11 -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