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https://github.com/heygen-com/hyperframes.git
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Miguel Ángel
6f04983e20
## Summary - When 2-3 renders run in parallel on Linux (beginFrame mode), Chrome's `HeadlessExperimental.beginFrame` fails with "Another frame is pending" due to CPU contention - Extracts `sendBeginFrame` helper with exponential backoff retry (50ms–800ms, 5 attempts) — used by both the main capture path and the hasDamage=false fallback - After retries exhaust, throws an actionable error instead of a raw protocol error ## Testing ### Environment - Linux (Ubuntu 20.04), 8 cores - `chrome-headless-shell` 146.0.7680.153 (beginFrame mode active) - Test composition: 1920×1080, 5s duration, 30fps, 150 frames, 3 GSAP-animated elements ### Before fix (main) Ran 3 parallel renders of the same composition simultaneously: | Render | Result | Details | |--------|--------|---------| | R1 | Completed | 304 KB, 6.6s | | R2 | **FAILED** | `Protocol error (HeadlessExperimental.beginFrame): Another frame is pending` at frame 120/150 | | R3 | Completed | 304 KB, 6.7s | The error is non-deterministic — it hits whichever worker loses the CDP frame contention race under CPU pressure. ### After fix (this branch) Same 3 parallel renders: | Render | Result | Details | |--------|--------|---------| | R1 | Completed | 304 KB, 7.3s | | R2 | Completed | 304 KB, 7.3s | | R3 | Completed | 304 KB, 7.3s | All 3 succeeded. The slight increase in wall time (6.6s → 7.3s) is consistent with occasional retries absorbing transient contention without failing. ### Code review - Both `beginFrame` call sites in `beginFrameCapture` (main capture path + hasDamage=false fallback) use the shared `sendBeginFrame` helper - Backoff ceiling is 1.55s per frame (50+100+200+400+800ms), acceptable for transient contention - beginFrame mode is Linux-only (`chrome-headless-shell` + `--enable-begin-frame-control`); macOS uses screenshot mode so the retry code path isn't exercised there
@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
Related packages
@hyperframes/core— types, parsers, frame adapters@hyperframes/producer— high-level render pipeline built on this enginehyperframes— CLI