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Vance IngallsandClaude Opus 5
2af3f4d0ed
Three defects in the PNG metadata fallback, all introduced when the cICP early return became an accumulator. Corrupt trailing chunk nulls a good result. cICP must precede IDAT, so continuing past it only visits chunks this parser ignores — while making whole-file integrity a precondition for returning anything. A truncated or bad-CRC chunk after cICP in an otherwise-good HDR PNG returned null, and extractMediaMetadata then re-throws the ffprobe error it had swallowed instead of using the fallback it just computed: the render dies on a host without FFmpeg, or grades SDR on a build that does not decode cICP. Now stops once dimensions and colour are known. A second IHDR overwrote the dimensions. PNG permits exactly one, first, but nothing enforced that here — a trailing [IHDR 1x1] replaced a real 3840x2160 and the producer laid out a one-pixel image. Anchored to the first. The length guard was also `>= 8` against a spec length of 13, which accepted a truncated header and read height out of the CRC bytes. crc32 was hand-rolled bit-at-a-time and fed a Buffer.concat per chunk. Since the walk no longer stops early it CRC'd whole files: 210 ms on a 12 MiB PNG, 647 ms on a 35 MiB 4K one, synchronously on the event loop, plus ~11 MB of garbage per parse from concatenating a 4-byte type tag onto every chunk. node:zlib's crc32 is native and takes a running seed, so type and data hash in sequence with no copy. 210.28 ms -> 1.291 ms. Tests: 5 regressions — corrupt-after-cICP, truncation after cICP, second IHDR, short IHDR, and that a corrupt IHDR/cICP still rejects. Reverting the break or the anchor fails 3. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
@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
Related packages
@hyperframes/core— types, parsers, frame adapters@hyperframes/producer— high-level render pipeline built on this enginehyperframes— CLI