* fix(core,producer,cli): pre-flight validation for empty/malformed sub-compositions The #1 render failure bucket in production telemetry (PostHog project 356858, dashboard 1783183 "HyperFrames — Bottom-Line & Activation"; ~65-69K occurrences / ~27-28K affected users over 30 days, ~80% via AI-agent authoring flows) is a `data-composition-src` reference pointing at a scene file that is empty, malformed, or missing. Root cause, traced end-to-end: - The literal error "Composition HTML is empty or could not be parsed: <path>" is real (not a PostHog paraphrase) — thrown by a since-reverted guard in packages/core/src/compiler/inlineSubCompositions.ts (#1364), then changed to a silent skip in #1678 to avoid aborting renders on partial content during authoring. #1629 added per-assembler guards for 3 skill workflows (product-launch-video, faceless-explainer, pr-to-video), but general-video and hand-authored flows — where the dominant filename `scene-title.html` (40K+/68K of the bucket) originates — have no assembler and thus no guard. #1678 assumed the assembler guards from #1629 covered this pre-render; they only covered 3 of the many authoring flows. - On current `main`, an empty/malformed data-composition-src file no longer crashes or throws during render — it's silently dropped by the tolerant inliner. Reproduced locally: `hyperframes render` on a project with an empty scene-title.html "succeeds" after ~93s (two 45s pollSubCompositionTimelines timeouts) with the scene silently missing from the output video. `hyperframes validate` also reports "No console errors" for the same broken project. - The raw `Cannot destructure property 'firstElementChild' of 'documentElement' as it is null` crash reproduces directly against linkedom (the DOMParser polyfill packages/cli/src/utils/dom.ts installs in the real CLI runtime) for empty and non-HTML input — confirmed with a standalone repro script, not just inferred. jsdom/happy-dom (used in this repo's own test environment) are spec-compliant and never produce a null documentElement, which is why this needed a linkedom-specific test file. Fix: - New shared helper `checkSubCompositionUsability` (packages/core/src/compiler/subCompositionValidity.ts) is the single source of truth for "is this data-composition-src file usable" — mirrors the inliner's own parse/template/body logic so all callers agree. - `inlineSubCompositions.ts` (preview/studio bundling) now uses the shared helper internally but keeps its #1678 tolerant skip-and-continue behavior unchanged — mid-authoring iteration on a partial project must keep working. `onMissingComposition` now also receives a human-readable reason. - New render-only pre-flight (`assertSubCompositionsUsable` in packages/producer/src/services/htmlCompiler.ts) walks every data-composition-src reference (including nested ones, root-relative, matching parseSubCompositions' own resolution) before any compilation work starts, and throws naming every offending file at once. This is unconditional — not gated behind --strict — because a render that silently drops a scene is strictly worse than one that refuses to start. Confirmed locally: render now fails in ~0.4s with an actionable message instead of "succeeding" after 93s with a missing scene. - New `hyperframes lint` rule `missing_or_empty_sub_composition` (packages/cli/src/utils/lintProject.ts) surfaces the same check as a file-scoped, actionable lint error (already unconditional — lint exits 1 on any error). - `hyperframes validate` now also runs this check before launching a browser, so it no longer reports "No console errors" for a project with a broken sub-composition. - `packages/core/src/parsers/htmlParser.ts`: guarded every `documentElement`-may-be-null access (parseHtml, updateElementInHtml, addElementToHtml, removeElementFromHtml, extractCompositionMetadata, validateCompositionHtml) with a new typed `CompositionHtmlParseError` (or, for validateCompositionHtml's collect-and-report contract, a typed validation failure) instead of a raw crash. Tests: empty file, whitespace-only, malformed/non-HTML, missing file, nested sub-compositions (both happy path and broken-grandchild), and the happy path — at the shared-helper, lint, and render pre-flight layers. Not changed: the AI-agent authoring skills (skills/*). general-video and hand-authored flows have no assemble-index.mjs equivalent to guard, so the fix is at the CLI/render layer instead — flow-agnostic, covers every authoring path, and the skills' existing "run lint/validate and stop on failure" guidance now actually catches this class of mistake once run. Not run in this environment: the producer package's full regression-harness test suite (`bun test` in packages/producer) — it performs heavy real rendering (S3 asset downloads, Google Fonts fetches, full video encodes) and did not complete in a reasonable time in this sandbox. Verified instead via the targeted test file for all touched code (76/76 passing), whole-repo typecheck/build/oxlint, `fallow audit` (complexity/duplication/dead-code gate, clean), and manual end-to-end CLI runs (render/lint/validate) against reproduction projects, including a nested sub-composition scenario. CI should run the full producer suite before merge. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> * refactor(parsers,lint): port empty-composition pre-flight to extracted packages Rebased onto main, which extracted @hyperframes/lint from core (lint depends only on parsers, not core). Relocate checkSubCompositionUsability from core to @hyperframes/parsers so both core (inliner) and lint can consume it without a core<->lint cycle; core keeps a @deprecated re-export shim. Correctness fixes from code review: - checkSubCompositionUsability now returns "no-composition-root" when the <template>/<body> content has no [data-composition-id] element (previously a marker-free placeholder body passed both guards). - lint's missing/empty sub-composition rule now only checks files reachable via data-composition-src from the root (matching render pre-flight), instead of a raw filesystem walk that false-positived on orphaned files. - drop `as string` cast in inlineSubCompositions in favor of an explicit null guard (per CLAUDE.md). Review-comment items: - move EmptyCompositionError JSDoc above the class (was above the adapter fn). - correct stale circular-ref comment to match actual silent-skip behavior. - rewrite self-contradicting lint message ("silently drop") to describe the new loud render-pre-flight abort. - add the __PLACEHOLDER__ (/^__[A-Z_]+__$/) skip to the render pre-flight so it agrees with lint. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
Write HTML. Render video. Built for agents.
Quickstart | Showcase | Playground | Catalog | Docs | Discord
HyperFrames is an open-source framework for turning HTML, CSS, media, and seekable animations into deterministic MP4 videos. Use it locally with the CLI, from AI coding agents with skills, or as the rendering core behind hosted authoring workflows.
Quick Start
With an AI coding agent
Install the HyperFrames skills, then describe the video you want:
npx skills add heygen-com/hyperframes
Try a prompt like:
Using
/hyperframes, create a 10-second product intro with a fade-in title, a background video, and subtle background music.
The skills teach agents the HyperFrames production loop: plan the video, write valid HTML, wire seekable animations, add media, lint, preview, and render. They work with Claude Code, Cursor, Gemini CLI, Codex, and other coding agents that support skills.
Skills
HyperFrames ships 19 skills agents load on demand. Read /hyperframes first — it's the router and capability map; it picks a workflow for any "make me a video" request and points to the domain skills below.
Run npx skills add heygen-com/hyperframes for the interactive picker, npx skills add heygen-com/hyperframes --all to install all 19 at once (skips the picker), or npx skills add heygen-com/hyperframes --skill <name> for just one (bare name, no leading /).
Router
| Skill | Use when |
|---|---|
/hyperframes |
Read first for any request to make / create / edit / animate / render a video, animation, or motion graphic. Capability map for the domain skills and intent router for the creation workflows below. |
Creation workflows
| Skill | Use when |
|---|---|
/product-launch-video |
Marketing / launching / promoting a product — from its URL, a brief, or a script (even if the site is only named). Up to ~3 min (sweet spot 30-90s). |
/website-to-video |
Turning a general website into a video — site tour, portfolio / landing-page showcase, social clip from the site's own visuals. |
/faceless-explainer |
Explaining a topic / concept from arbitrary text — no product, no URL, no website capture; every visual is LLM-invented (typography / abstract / diagram / data-viz). |
/pr-to-video |
A GitHub pull request (PR URL, owner/repo#N ref, or "this PR") → changelog / feature-reveal / fix / refactor explainer, read via the gh CLI. |
/embedded-captions |
Adding captions / subtitles to an existing talking-head video (footage untouched) — verbatim rail, embedded climax behind the subject, or pure-cinematic embed. |
/talking-head-recut |
Packaging an existing talking-head / interview / podcast video with designed graphic overlays — lower-thirds, data callouts, kinetic titles, pull-quotes, side panels, PiP. |
/motion-graphics |
A short, unnarrated, design-led motion graphic (~under 10s) — kinetic type, stat / chart hit, logo sting, lower-third, animated tweet / headline. MP4 or transparent overlay. |
/music-to-video |
A music track (audio file, or video to pull audio from) → a beat-synced video — lyric, slideshow, or kinetic promo; music drives pacing. |
/slideshow |
A presentation / pitch deck / interactive deck — discrete slides, fragment reveals, branching, hotspot navigation, presenter mode. Output is a navigable deck, not a rendered video. |
/general-video |
Anything else — longer or multi-scene pieces, brand / sizzle reel, title card, static loop, freeform composition. Input- and length-agnostic fallback. |
/remotion-to-hyperframes |
Porting an existing Remotion (React) composition's source to HyperFrames HTML. One-way migration, not creation. |
Domain skills (loaded on demand)
Atomic capabilities the creation workflows compose against — pull one when you need that specific layer.
| Skill | Covers |
|---|---|
/hyperframes-core |
The composition contract — data-* timing attributes, class="clip", tracks, sub-compositions, variables, framework-owned media playback, determinism rules. |
/hyperframes-animation |
All animation knowledge — atomic motion rules, scene blueprints, transitions, runtime adapters (GSAP / Lottie / Three.js / Anime.js / CSS / WAAPI / TypeGPU). |
/hyperframes-creative |
Non-animation creative direction — frame.md / design.md, palettes, typography, narration, beat planning, audio-reactive visuals, composition patterns. |
/hyperframes-media |
Audio + media — TTS voiceover, background music, sound effects, Whisper transcription, background removal, caption authoring (one shared audio engine). |
/media-use |
Resolve any media need (BGM, SFX, image, icon) into a frozen local file + ledger record. One verb (resolve) over the HeyGen catalog with manifest tracking. |
/hyperframes-cli |
CLI dev loop — init, lint, validate, inspect, preview, render, publish, doctor, plus AWS Lambda cloud rendering (lambda deploy / render / progress). |
/hyperframes-registry |
Install and wire registry blocks and components into compositions via hyperframes add. Authoring a new block or component to contribute upstream. |
For visual design handoff workflows, see the Claude Design guide and Open Design guide.
Manually with the CLI
npx hyperframes init my-video
cd my-video
npx hyperframes preview # preview in browser with live reload
npx hyperframes render # render to MP4
Requirements: Node.js 22+, FFmpeg
What You Can Build
Need ideas? Browse the Showcase for finished videos you can watch, read, run, and remix.
- Product launch videos and feature announcements
- PR walkthroughs with animated code diffs, narration, and captions
- Data visualizations, chart races, and map animations
- Social videos with kinetic captions, overlays, and music
- Docs-to-video, PDF-to-video, and website-to-video explainers
- Reusable motion graphics for automated content pipelines
Frame.md
frame.md — your design system, ready for video.
Every brand has a design.md. None of them were written for a camera. frame.md is the missing translation layer: it takes your web-context design spec and inverts it for the frame — the same tokens, the same rules, but rewritten so an AI agent can compose a promo video without guessing at scale or reaching for web chrome.
The output is a DESIGN.md superset your whole toolchain can read. Atoms stay sacred. Composition stays free. Numbers come from the script.
Biennale Yellow |
BlockFrame |
Blue Professional |
Bold Poster |
Broadside |
Capsule |
Cartesian |
Cobalt Grid |
Coral |
Creative Mode |
Browse and remix them all at hyperframes.dev/design.
How It Works
Define a video as HTML. Add data attributes for timing and tracks. Use GSAP, CSS, Lottie, Three.js, Anime.js, WAAPI, or your own frame adapter for seekable animation.
<div id="stage" data-composition-id="launch" data-start="0" data-width="1920" data-height="1080">
<video
class="clip"
data-start="0"
data-duration="6"
data-track-index="0"
src="intro.mp4"
muted
playsinline
></video>
<h1 id="title" class="clip" data-start="1" data-duration="4" data-track-index="1">Launch day</h1>
<audio
data-start="0"
data-duration="6"
data-track-index="2"
data-volume="0.5"
src="music.wav"
></audio>
<script src="https://cdn.jsdelivr.net/npm/gsap@3/dist/gsap.min.js"></script>
<script>
const tl = gsap.timeline({ paused: true });
tl.from("#title", { opacity: 0, y: 40, duration: 0.8 }, 1);
window.__timelines = window.__timelines || {};
window.__timelines.launch = tl;
</script>
</div>
Preview instantly in the browser. Render locally or in Docker. The renderer seeks each frame in headless Chrome and encodes the result with FFmpeg, so the same input produces the same video.
HyperFrames Stack
HyperFrames is the open-source rendering engine, plus a growing set of tools around HTML-native video creation.
| Piece | Status | What it does |
|---|---|---|
| CLI | Available | Scaffold, preview, lint, inspect, and render local video projects |
| Core / Engine / Producer | Available | Parse compositions, drive headless Chrome, encode video, and mix audio |
| Catalog | Available | Reusable blocks and components for transitions, overlays, captions, charts, maps, and effects |
| Agent skills | Available | Teach coding agents the video-production patterns that generic web docs miss |
| Studio | Available, evolving | Browser surface for previewing and editing compositions |
| AWS Lambda rendering | Available | Deploy a distributed render stack and drive renders from your laptop or CI |
| hyperframes.dev | Available | Community playground for previewing, iterating, sharing, and rendering HTML-native video projects |
| frame.md | Available | Invert your design system for the camera — a DESIGN.md superset an agent can compose video from |
Catalog
Install ready-to-use blocks and components:
npx hyperframes add flash-through-white # shader transition
npx hyperframes add instagram-follow # social overlay
npx hyperframes add data-chart # animated chart
Browse the catalog at hyperframes.heygen.com/catalog.
Why HyperFrames?
- HTML-native: compositions are HTML files with data attributes. No React requirement, no proprietary timeline format.
- Agent-friendly: agents already write HTML, and the CLI is non-interactive by default.
- Deterministic: same input, same frames, same output. Built for CI, regression tests, and automated rendering.
- No build step: an
index.htmlcomposition plays as-is and can be previewed directly in the browser. - Adapter-based animation: bring GSAP, CSS animations, Lottie, Three.js, Anime.js, WAAPI, or a custom runtime.
- Open source: Apache 2.0 license, with no per-render fees or commercial-use thresholds.
HyperFrames vs Remotion
HyperFrames is inspired by Remotion. Both tools render video with headless Chrome and FFmpeg. The main difference is the authoring model: Remotion's bet is React components; HyperFrames' bet is plain HTML that humans and agents can both write easily.
| HyperFrames | Remotion | |
|---|---|---|
| Authoring | HTML + CSS + seekable animation | React components |
| Build step | None; index.html plays as-is |
Bundler required |
| Agent handoff | Plain HTML files | JSX / React project |
| Library-clock animations | Seekable, frame-accurate via adapters | Wall-clock animation patterns need care |
| Distributed rendering | Local and AWS Lambda render paths | Remotion Lambda, mature cloud renderer |
| License | Apache 2.0 | Source-available Remotion License |
Read the full comparison in the HyperFrames vs Remotion guide.
Documentation
Full documentation: hyperframes.heygen.com/introduction
Packages
| Package | Description |
|---|---|
hyperframes |
CLI for creating, previewing, linting, and rendering compositions |
@hyperframes/core |
Types, parsers, generators, linter, runtime, and frame adapters |
@hyperframes/engine |
Seekable page-to-video capture engine using Puppeteer and FFmpeg |
@hyperframes/producer |
Full rendering pipeline for capture, encode, and audio mix |
@hyperframes/studio |
Browser-based composition editor UI |
@hyperframes/player |
Embeddable <hyperframes-player> web component |
@hyperframes/shader-transitions |
WebGL shader transitions for compositions |
@hyperframes/aws-lambda |
AWS Lambda SDK and deployment surface for distributed renders |
Community
HyperFrames is used in production at HeyGen, with community examples from teams like tldraw, TanStack, and others in ADOPTERS.md. Open a PR if your team is using HyperFrames.
- Questions and ideas: Discord
- Bugs and feature requests: GitHub Issues
- Security reports: SECURITY.md
- Contributions: CONTRIBUTING.md
Development Note
The repo uses Git LFS for golden regression-test baselines under packages/producer/tests/**/output.mp4 (about 240 MB of .mp4 files). If you're cloning the full repo for development, install Git LFS first:
# macOS
brew install git-lfs
# Ubuntu / Debian
sudo apt install git-lfs
# Windows
winget install GitHub.GitLFS
# Then, once per machine
git lfs install
If you only need source files, you can skip LFS content:
GIT_LFS_SKIP_SMUDGE=1 git clone https://github.com/heygen-com/hyperframes.git










