Files
hyperframes/packages/engine
Miguel ÁngelandVance Ingalls 9308eadcfc fix(render): bound and recover capture stalls (#3700)
* test(producer): pin unpinned drawElement stall retry

* fix(engine): bound drawElement frames so a wedged renderer falls back instead of failing (#3172)

* fix(engine): bound drawElement frames so a wedged renderer falls back instead of failing

A single drawElement frame could kill an entire render. On one comp
(caption-editorial-emphasis) drawElementImage returns normally and the renderer
then stops draining its task queue: the setTimeout(…, 0) that schedules
toDataURL never fires, the capture page.evaluate never settles, and 60s later
the stage watchdog fails the whole render. Deterministic on 152.0.7977.30,
always the same frame. Root-cause detail in PRINFRA-488.

Two gaps, both closed here.

1. Nothing below the 60s stage watchdog bounded a frame. Adds a per-frame
   deadline (HF_DE_FRAME_TIMEOUT_MS, default 15000, 0 disables) around the WHOLE
   frame operation, not just the drawElementImage call — the stall surfaces at
   whichever page round-trip comes next, and was observed at both the capture
   and the seek's background-image decode. Bounding one call missed it.

   Deliberately NO per-frame screenshot fallback for this error: once the
   renderer stops scheduling it is wedged for every subsequent round-trip on
   that page. Measured — the screenshot fallback blew the same deadline. The
   frame fails fast instead, so the recovery that actually works can run.

2. That recovery was ineligible. shouldRetryViaPinnedFallback only retried a
   generic capture failure when the worker count was PINNED by the inversion or
   the router; a comp that engaged drawElement on the ordinary single-worker
   path had no whole-render fallback at all. A renderer stall is now retryable
   on any routing — the failure is a property of drawElement itself, and the
   retry re-renders on a fresh page via screenshot. Reported as
   de_fallback_reason "de_renderer_stall" so it is distinguishable from
   capture_error in telemetry, and counted per-session as deFrameTimeouts.

Verified end to end on the repro: previously exit 1 with "stalled: no frame
progress for 60000ms"; now the deadline fires, the render retries via
screenshot, and RENDER_OK with a valid 1920x1080 / 240-frame / 8.0s MP4.

Tests cover the predicate both ways plus the cross-package error match. Engine
1,481 and producer 587 green (audioPadTrim.integration flakes only under
full-suite parallel load — passes in isolation, and on clean HEAD it is green
too, so it is not from this change).

Refs PRINFRA-488

* fix(engine,producer,cli): count drawElement frame timeouts where they happen

`session.deFrameTimeouts` was incremented inside `captureFrameCore`'s catch,
but the deadline races that function from OUTSIDE it — `withFrameDeadline` is
applied by `captureFrameToBuffer`, and `DeFrameTimeoutError` is constructed
nowhere else. So the branch was unreachable: on a wedged renderer the counter
stayed 0, the engine-side stall log never printed, and
`CapturePerfSummary.deFrameTimeouts` reported 0 on every affected render. The
end-to-end recovery worked throughout — `isDeRendererStallError` matches by
name at the producer — only the observability was dead.

Moved the increment and the log into an `onTimeout` hook that fires from the
deadline itself, deleted the unreachable branch and the now-unused
`isDeFrameTimeoutError`, and threaded the count out to
`render_completed.de_frame_timeouts` so the rate is graphable apart from the
other `capture_error` fallbacks. A stall always costs a whole-render re-run,
which is why it deserves its own series.

Also corrected the `fallbackReason` docstring, which still listed only
`psnr | blank | oom | capture_error` after this branch added
`de_renderer_stall`.

`withFrameDeadline` is exported for a two-case fake-timer test: the deadline
fires and calls `onTimeout` once, and a resolving inner promise passes its
value through with no late timer. The first case fails if the counter moves
back inside the work promise.

(cherry picked from commit ec2b2b5b2a)

* fix(render): retry sequential screenshot stalls

* fix(render): bound parallel worker capture phases

---------

Co-authored-by: Vance Ingalls <vance@heygen.com>
2026-09-08 18:10:28 +00:00
..
2026-09-07 12:12:35 -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,
  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