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hyperframes/packages/producer
Vance Ingalls 8548a17771 feat(hdr): GSAP transforms and border-radius masks on HDR video (#290)
## Summary

HDR video elements with GSAP animations (position, scale, rotation, opacity) and CSS border-radius rendered without any transforms applied — the video just sat at (0,0) full-size. This PR adds affine transform support and rounded-corner masking for natively-composited HDR video.

## What it does

**Affine blit with bilinear interpolation:**
- `blitRgb48leAffine()` — Takes a 4x4 DOMMatrix and maps each destination pixel back to source coordinates via the inverse transform. Bilinear interpolation between the 4 nearest source pixels produces smooth edges under rotation and non-integer scaling. Optional opacity and border-radius parameters.
- `parseTransformMatrix()` — Parses CSS `matrix(a,b,c,d,e,f)` strings into `[a,b,c,d,e,f]` tuples.

**Accumulated viewport matrix:**
- `getViewportMatrix()` — Walks the `offsetParent` chain from element to viewport, accumulating position offsets and CSS transforms at each level. Correctly handles `transform-origin` using the CSS sandwich: `translate(origin) × M × translate(-origin)`. This is critical because GSAP animates transforms on wrapper divs, not directly on the video element.

**Effective opacity:**
- `getEffectiveOpacity()` — Multiplies opacity values walking up the ancestor chain. Uses `Number.isNaN()` (not `|| 1`) so opacity:0 isn't incorrectly treated as 1.

**Border-radius masks:**
- `roundedRectAlpha()` — Per-pixel anti-aliased rounded-rectangle mask with support for independent corner radii.
- `getEffectiveBorderRadius()` — Walks ancestors for `overflow:hidden` + border-radius. Resolves percentage values (e.g., `50%` for circles) via `offsetWidth`/`offsetHeight`.

**Layout dimensions for extraction:**
- Uses `offsetWidth`/`offsetHeight` (unaffected by CSS transforms) instead of `getBoundingClientRect()` (which returns the transformed bounding box and wobbles under rotation).

## Files changed

| File | What changed |
|------|-------------|
| `packages/engine/src/utils/alphaBlit.ts` | `blitRgb48leAffine()`, `parseTransformMatrix()`, `roundedRectAlpha()`, `cornerAlpha()` |
| `packages/engine/src/services/videoFrameInjector.ts` | `getViewportMatrix()`, `getEffectiveOpacity()`, `getEffectiveBorderRadius()`, `layoutWidth`/`layoutHeight` on `ElementStackingInfo` |
| `packages/producer/src/services/renderOrchestrator.ts` | Affine blit path, extraction at layout dimensions, border-radius parameter passing |

## How to test

Render a composition with an HDR video that has GSAP scale + rotation animation and a `border-radius: 50%` wrapper (circle mask). The video should rotate smoothly with round edges — no wobble, no sharp corners.

## Stack position

**5 of 6** — Stacked on #289 (z-ordered layers). Adds transform and masking support to the HDR blit that the layer compositor uses.

🤖 Generated with [Claude Code](https://claude.com/claude-code)
2026-04-19 17:03:29 -07:00
..
2026-04-19 23:35:35 +00:00

@hyperframes/producer

Full HTML-to-video rendering pipeline: capture frames with Chrome's BeginFrame API, encode with FFmpeg, mix audio — all in one call.

Install

npm install @hyperframes/producer

Requirements: Node.js >= 22, Chrome/Chromium (auto-downloaded), FFmpeg

Usage

Render a video

import { createRenderJob, executeRenderJob } from "@hyperframes/producer";

const job = createRenderJob({
  inputPath: "./my-composition.html",
  outputPath: "./output.mp4",
  width: 1920,
  height: 1080,
  fps: 30,
});

const result = await executeRenderJob(job, (progress) => {
  console.log(`${Math.round(progress.percent * 100)}%`);
});

console.log(result.outputPath); // ./output.mp4

Run as an HTTP server

The producer can also run as a render server, accepting render requests over HTTP:

import { startServer } from "@hyperframes/producer";

await startServer({ port: 8080 });
// POST /render with a RenderConfig body

Configuration

RenderConfig controls the render pipeline:

Option Default Description
inputPath Path to the HTML composition
outputPath Output video file path
width 1920 Frame width in pixels
height 1080 Frame height in pixels
fps 30 Frames per second (24, 30, or 60)
quality "standard" Encoder preset ("draft", "standard", "high")

How it works

  1. Serve — spins up a local file server for the HTML composition
  2. Capture — opens the page in headless Chrome, seeks frame-by-frame via HeadlessExperimental.beginFrame, captures screenshots
  3. Encode — pipes frames through FFmpeg (with GPU encoder detection and chunked concat)
  4. Mix — extracts <audio> elements and mixes them into the final video
  5. Finalize — applies faststart for streaming-friendly MP4

Documentation

Full documentation: hyperframes.heygen.com/packages/producer