Files
hyperframes/packages/engine
Vance Ingalls cc9403b6bd test(producer): extract frameDirMaxIndexCache to its own module and pin cross-job isolation (#381)
## Summary

Extract the `frameDirMaxIndexCache` from a private module-scoped Map inside `renderOrchestrator.ts` into its own `frameDirCache.ts` module, then add a 11-test bun:test suite that pins the cross-job isolation contract added in Chunk 5B.

## Why

`Chunk 9E` of `plans/hdr-followups.md`. The cache lived as a private Map inside `renderOrchestrator.ts`, which made the cross-job isolation contract from Chunk 5B impossible to unit-test directly. Extracting it both makes the contract testable and reduces orchestrator complexity slightly.

## What changed

- New `packages/producer/src/services/frameDirCache.ts` exposes `getMaxFrameIndex` / `clearMaxFrameIndex` / `getMaxFrameIndexCacheSize` (plus a test-only `__resetMaxFrameIndexCacheForTests` helper). Behavior is unchanged: callers still get the same module-scoped sharing inside a job, and `renderOrchestrator`'s outer `finally` still clears every entry it registered so the cache cannot grow monotonically across renders.
- `renderOrchestrator.ts`: imports the new helpers, drops the unused `readdirSync` import, updates inline comments, and replaces two `frameDirMaxIndexCache.delete` sites with `clearMaxFrameIndex`.
- New `frameDirCache.test.ts` (bun:test, 11 tests) covering:
  - Reading the max index from a populated directory.
  - Ignoring filenames that don't match `frame_NNNN.png` (wrong ext, wrong prefix, wrong case, double extension, empty index group, same-named subdirectory).
  - Empty- and missing-directory paths returning `0` and being cached.
  - Intra-job invariant: subsequent readdir mutations not observed once cached.
  - `clearMaxFrameIndex` forcing a re-read; returns `false` for paths that were never cached.
  - Per-directory isolation when multiple directories are registered.
  - The cross-job contract from Chunk 5B: cache empty between well-behaved jobs, doesn't grow monotonically across 20 simulated renders with 3 HDR videos each (steady-state cache size stays at 3), and a buggy job that forgets to clear leaks exactly its own entries rather than affecting unrelated jobs.

## Test plan

- [x] `frameDirCache.test.ts` 11/11 pass.
- [x] Existing producer tests unchanged.
- [x] Behavior preserved: same module-scoped sharing inside a job, same outer-`finally` eviction.

## Stack

Chunk 9E of `plans/hdr-followups.md`. Test-driven extraction; complements Chunk 5B.
2026-04-23 14:29:36 -07:00
..
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,
  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