Vance Ingalls 5a3fde19d4 feat(engine): add HDR video output pipeline (#265)
## Summary

Adds the ability to render HDR video output (H.265 10-bit, BT.2020) from HyperFrames compositions. When the renderer detects HDR source video, it automatically switches to the HDR output pipeline — no flags needed.

## What it does

- **Auto-detection** — Probes each video source with `ffprobe`. If any has bt2020/PQ/HLG color metadata, the output switches to H.265 10-bit with correct color tags. SDR-only compositions are unaffected (H.264, bt709).
- **HLG pass-through** — Native HLG pixels from FFmpeg extraction are piped directly to the encoder without conversion. This avoids brightness loss from HLG→linear→PQ conversion (which requires an OOTF system gamma we can't reliably apply).
- **Encoder HDR support** — Both chunk and streaming encoders accept HDR presets: `libx265`, `yuv420p10le`, BT.2020 color primaries, `hvc1` codec tag (required for Apple playback).
- **WebGPU HDR capture (gated)** — A complete WebGPU float16 readback pipeline is implemented and tested but gated behind headed Chrome (headless doesn't expose WebGPU). Ready for future use with WebGPU canvas content.
- **HDR utilities** — `detectTransfer()` (PQ vs HLG), `getHdrEncoderColorParams()`, `analyzeCompositionHdr()`. 15 unit tests.

## Key design decisions

| Decision | Why |
|----------|-----|
| No `--hdr` flag | SDR content encoded as HDR causes orange shift in browsers. Auto-detect eliminates this. |
| HLG pass-through (not HLG→PQ) | Conversion loses brightness without OOTF. Pass-through matches source exactly. |
| `hvc1` codec tag | Apple QuickTime requires `hvc1` (not `hev1`) for HEVC playback. |
| 1-hour streaming timeout | HDR capture at ~6fps needs more time than the default 10-minute FFmpeg timeout. |

## Files changed

| File | What changed |
|------|-------------|
| `packages/engine/src/utils/hdr.ts` | **NEW** — HDR detection, transfer types, encoder params (15 tests) |
| `packages/engine/src/services/hdrCapture.ts` | **NEW** — WebGPU readback, HLG conversion, PQ encode |
| `packages/engine/src/services/streamingEncoder.ts` | HDR presets, raw rgb48le input, color tags |
| `packages/engine/src/services/chunkEncoder.ts` | HDR presets, conditional color tags |
| `packages/producer/src/services/renderOrchestrator.ts` | Auto-detection loop, HDR pass-through capture path |

## How to test

Render a composition with an HDR video source. The output should be H.265 10-bit with HDR metadata visible in `ffprobe` (bt2020, arib-std-b67 or smpte2084). Plays correctly in QuickTime and on HDR displays.

## Stack position

**2 of 6** — Stacked on #258 (SDR/HDR normalization). Provides the encoder infrastructure that phases 1-5 build on.

🤖 Generated with [Claude Code](https://claude.com/claude-code)
2026-04-19 15:10:59 -07:00
2026-03-21 22:43:56 -07:00

HyperFrames

npm version npm downloads License Node.js

Write HTML. Render video. Built for agents.

HyperFrames demo — HTML code on the left transforms into a rendered video on the right

Hyperframes is an open-source video rendering framework that lets you create, preview, and render HTML-based video compositions — with first-class support for AI agents.

Quick Start

Install the HyperFrames skills, then describe the video you want:

npx skills add heygen-com/hyperframes

This teaches your agent (Claude Code, Cursor, Gemini CLI, Codex) how to write correct compositions and GSAP animations. In Claude Code, the skills register as slash commands — invoke /hyperframes to author compositions, /hyperframes-cli for CLI commands, and /gsap for animation help.

Try it: example prompts

Copy any of these into your agent to get started. The /hyperframes prefix loads the skill context explicitly so you get correct output the first time.

Cold start — describe what you want:

Using /hyperframes, create a 10-second product intro with a fade-in title, a background video, and background music.

Warm start — turn existing context into a video:

Take a look at this GitHub repo https://github.com/heygen-com/hyperframes and explain its uses and architecture to me using /hyperframes.

Summarize the attached PDF into a 45-second pitch video using /hyperframes.

Turn this CSV into an animated bar chart race using /hyperframes.

Format-specific:

Make a 9:16 TikTok-style hook video about [topic] using /hyperframes, with bouncy captions synced to a TTS narration.

Iterate — talk to the agent like a video editor:

Make the title 2x bigger, swap to dark mode, and add a fade-out at the end.

Add a lower third at 0:03 with my name and title.

The agent handles scaffolding, animation, and rendering. See the prompting guide for more patterns.

Option 2: Start a project manually

npx hyperframes init my-video
cd my-video
npx hyperframes preview      # preview in browser (live reload)
npx hyperframes render       # render to MP4

hyperframes init installs skills automatically, so you can hand off to your AI agent at any point.

Requirements: Node.js >= 22, FFmpeg

Why Hyperframes?

  • HTML-native — compositions are HTML files with data attributes. No React, no proprietary DSL.
  • AI-first — agents already speak HTML. The CLI is non-interactive by default, designed for agent-driven workflows.
  • Deterministic rendering — same input = identical output. Built for automated pipelines.
  • Frame Adapter pattern — bring your own animation runtime (GSAP, Lottie, CSS, Three.js).

How It Works

Define your video as HTML with data attributes:

<div id="stage" data-composition-id="my-video" data-start="0" data-width="1920" data-height="1080">
  <video
    id="clip-1"
    data-start="0"
    data-duration="5"
    data-track-index="0"
    src="intro.mp4"
    muted
    playsinline
  ></video>
  <img
    id="overlay"
    class="clip"
    data-start="2"
    data-duration="3"
    data-track-index="1"
    src="logo.png"
  />
  <audio
    id="bg-music"
    data-start="0"
    data-duration="9"
    data-track-index="2"
    data-volume="0.5"
    src="music.wav"
  ></audio>
</div>

Preview instantly in the browser. Render to MP4 locally or in Docker.

Catalog

50+ ready-to-use blocks and components — social overlays, shader transitions, data visualizations, and cinematic effects:

npx hyperframes add flash-through-white   # shader transition
npx hyperframes add instagram-follow      # social overlay
npx hyperframes add data-chart            # animated chart

Browse the full catalog at hyperframes.heygen.com/catalog.

Documentation

Full documentation at hyperframes.heygen.com/introductionQuickstart | Guides | API Reference | Catalog

Packages

Package Description
hyperframes CLI — create, preview, lint, and render compositions
@hyperframes/core Types, parsers, generators, linter, runtime, frame adapters
@hyperframes/engine Seekable page-to-video capture engine (Puppeteer + FFmpeg)
@hyperframes/producer Full rendering pipeline (capture + encode + audio mix)
@hyperframes/studio Browser-based composition editor UI
@hyperframes/player Embeddable <hyperframes-player> web component
@hyperframes/shader-transitions WebGL shader transitions for compositions

Skills

HyperFrames ships skills that teach AI agents framework-specific patterns that generic docs don't cover.

npx skills add heygen-com/hyperframes
Skill What it teaches
hyperframes HTML composition authoring, captions, TTS, audio-reactive animation, transitions
hyperframes-cli CLI commands: init, lint, preview, render, transcribe, tts, doctor
hyperframes-registry Block and component installation via hyperframes add
gsap GSAP animation API, timelines, easing, ScrollTrigger, plugins, React/Vue/Svelte, performance

Contributing

See CONTRIBUTING.md for guidelines.

License

Apache 2.0

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