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Vance Ingalls
9f18e9ea11
Chunk 3 of HDR follow-ups. Three independent fixes that share a common
thread: HDR config flowing correctly from the EngineConfig down through
the encoders.
3A. chunkEncoder respects options.hdr (BT.2020 + mastering metadata)
Previously buildEncoderArgs hard-coded BT.709 color tags and the
bt709 VUI block in -x265-params, even when callers passed an HDR
EncoderOptions. Today this is harmless because renderOrchestrator
routes native-HDR content to streamingEncoder and only feeds
chunkEncoder sRGB Chrome screenshots — but the contract was a lie.
Now: when options.hdr is set, the libx265 software path emits
bt2020nc + the matching transfer (smpte2084 for PQ,
arib-std-b67 for HLG) at the codec level *and* embeds
master-display + max-cll SEI in -x265-params via
getHdrEncoderColorParams. libx264 still tags BT.709 inside
-x264-params (libx264 has no HDR support) but the codec-level color
flags flip so the container describes pixels truthfully. GPU
H.265 (nvenc/videotoolbox/qsv/vaapi) gets the BT.2020 tags but no
-x265-params block, so static mastering metadata is omitted —
acceptable for previews, not HDR-aware delivery.
3B. convertSdrToHdr accepts a target transfer
videoFrameExtractor.convertSdrToHdr was hard-coded to
transfer=arib-std-b67 (HLG) regardless of the surrounding
composition's dominant transfer. extractAllVideoFrames now calls
analyzeCompositionHdr first, then passes the dominant transfer
("pq" or "hlg") into convertSdrToHdr so an SDR clip mixed into a PQ
timeline gets converted with smpte2084, not arib-std-b67.
3C. EngineConfig.hdr type matches its declared shape
The IIFE for the hdr field returned undefined when
PRODUCER_HDR_TRANSFER wasn't "hlg" or "pq", but the field is typed
as { transfer: HdrTransfer } | false. Returning false matches the
type and avoids a downstream undefined check.
Tests
- chunkEncoder.test.ts: replaced the previous "HDR options ignored"
assertions with 8 new specs covering BT.2020 + transfer tagging,
master-display/max-cll embedding, libx264 fallback behavior, GPU
H.265 + HDR (tags but no x265-params), and range conversion for
both SDR and HDR CPU paths.
- All 313 engine unit tests pass (5 new HDR specs).
Follow-ups (separate PRs):
- Producer regression suite runs in CI; not exercising HDR-tagged
chunkEncoder yet because no live caller sets options.hdr 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