mirror of
https://github.com/heygen-com/hyperframes.git
synced 2026-11-15 13:58:20 +00:00
Vance IngallsandClaude Opus 5
55f852a723
`writeWav` clamps and quantises the chain's float output to int16, and the
mixer only ran `applyVolumeEnvelopeToWav` over that file afterwards. So a
chain that overshoots full scale was destructively clipped even when the
volume lane immediately pulled the track 12 dB down — audible distortion
baked into the render that preview, working in float throughout, never had.
Measured on 12 s of narration through a +12 dB peaking band into saturation
with the lane holding the track at -12 dB: the chain peaks at 1.346, so the
old order sheared 19,166 samples (1.7%) flat against ±1 before ducking. Level
matched, the two renders differ by an error signal 26.3 dB below the audio,
worst single-sample delta 0.242.
The envelope now travels into `applyAudioFxChain` and lands on the float
planes before `writeWav` sees them; the mixer runs its own pass only for a
track the FX pass did not bake. `writeWav`'s clamp stays — it is the correct
last resort for a signal still hot after the duck, just no longer the first
thing that happens.
The per-frame segment-cursor gain walk is extracted as `createEnvelopeWalker`
so both bakers share one implementation, and the ffmpeg-expression fallback
for non-int16 WAVs is untouched.
`applyAudioFxChain` now returns `{ path, envelopeBaked }` rather than a bare
path: inferring the bake from `path !== inputWav` would silently break on the
two early returns (empty chain, empty track).
The new test is stereo with a step in the envelope, so it also falsifies a
per-plane walk — restarting the cursor for a second channel hands it the tail
gain for its whole length. Falsified against three mutations: clamp-then-duck
(0.5 instead of 0.9), envelope dropped (1.0), plane-outer walk (0.449).
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