Files
hyperframes/packages/engine
Vance IngallsandClaude Opus 5 07203f59d1 fix(engine): keep a group's headroom through its FX chain, not just up to it
Residual of finding 8, found by following the float sub-mix downstream
instead of stopping at the file it writes.

The float intermediate fixed the clip for a group with no FX chain. A
group WITH one runs that sum through applyAudioFxChain, whose writeWav
clamps to ±1 and emits 16-bit — so the headroom was handed straight back
one step later, still upstream of the fader. Same bug, same shape, one
node further along: measured 1.6 dB hot on two 0.7-peak tones summing to
1.4 under a transparent 0 dB chain and a 0.5 group fader.

writeWav now takes a `float` flag and readWav reports the format it read,
so the FX pass writes back whatever it was handed. Only the group
sub-mix is float; every element track is still 16-bit, which is what the
envelope baker wanted when that was made 16-bit in the first place. Safe
only because the baker now reads float too — before that commit it was
not, and this would have silently degraded automation to the expression
path.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-20 16:39:38 -07:00
..
2026-08-20 19:03:09 -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