* fix(runtime): auto-infer composition duration for CSS/WAAPI/Lottie so data-duration is optional The #2 render failure bucket ("Composition has zero duration") accounts for ~27K errors / ~7K affected users over 30 days (PostHog project 356858). Root cause: only GSAP timelines got their duration auto-detected — CSS, WAAPI, and Lottie compositions had no source of truth for total duration unless the author remembered to set data-duration on the root element, and the render engine hard-failed capture when neither was present. Adds getInferredDurationSeconds() to the CSS, WAAPI, and Lottie runtime adapters (packages/core/src/runtime/adapters/*.ts) — each reports the longest finite end time it can discover from its own animations (CSS: computed timing offset by data-start; WAAPI: effect.getComputedTiming().endTime; Lottie: totalFrames/frameRate or the player's own duration). Infinite/ unbounded animations correctly return null and still require data-duration. Wires this into the runtime's existing duration-floor resolution (resolveAdapterDurationFloorSeconds in runtime/init.ts), alongside the existing media-duration and authored-composition floors, so window.__hf.duration becomes positive without any author action for finite-duration non-GSAP compositions. Three.js is unchanged — no AnimationClip/AnimationMixer inspection exists in that adapter, so data-duration remains required there. Tightens frameCapture.ts's zero-duration fast-fail gate to also check hf.duration directly (not just the two authored signals), so a composition mid-inference isn't fast-failed before its adapter-derived duration lands. Adds a new lint rule (root_composition_missing_duration_source) that errors only on genuinely non-inferable cases: no animation signal at all, Three.js without data-duration, or an infinite/unbounded CSS or WAAPI animation without data-duration. Deliberately silent on finite CSS/WAAPI/Lottie animations, since the runtime now infers those — an autofix that "inserts the inferred value" was considered and rejected: every case the rule flags has no derivable value (an infinite spinner has no finite end time; a duration-less Three.js scene has nothing to measure), so any autofix would have to fabricate a placeholder, trading a loud correct failure for a silent wrong-length render. Updates the CSS/WAAPI/Lottie/Three adapter skill docs and the hyperframes-core determinism-rules/data-attributes references to document the new optionality and the runtime mechanism backing it. Verified end-to-end against the real render pipeline (not just unit tests): a CSS-only composition with a finite 3s animation, no GSAP timeline, and no data-duration now renders a correct 3.000s MP4 via `hyperframes render` (previously: "Composition has zero duration" failure). The infinite-CSS negative control still fails fast with a clear diagnostic, matching the new lint rule. Adds a file-level fallow health exemption for lottie.ts's pre-existing `seek` handler — unrelated to this change, but its line numbers shifted when new functions were added earlier in the file, tripping fallow's inherited-finding fingerprint (documented pattern already used elsewhere in .fallowrc.jsonc for the same reason). Known limitation: the static WAAPI usage detector in the lint rule (/\.animate\(\s*[\[$A-Za-z_]/) can miss unusual call shapes; it only affects whether the "no signal at all" branch fires, and errs toward NOT flagging (reducing false positives) rather than over-flagging. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> * fix(lint): close 3 correctness gaps in root_composition_missing_duration_source - Strip JS/CSS comments before scanning for GSAP/WAAPI/Three/Lottie/CSS animation signals, so a commented-out `.animate()` call or a commented `animation: ... infinite` rule can no longer satisfy the "has a duration source" check and mask a real zero-duration render failure. - Broaden the WAAPI detection regex to also match the object-literal (PropertyIndexedKeyframes) form of `.animate()`, e.g. `el.animate({ opacity: [0,1] }, { duration: 2000 })`, which the previous character class silently missed. Corrected the adjacent comment that incorrectly claimed this shape "can't be a false negative". - Fix hasInfiniteCssAnimation to stop false-positiving on animation NAMEs that merely contain the substring "infinite" (e.g. `infinite-spin`) by anchoring the `infinite` keyword with hyphen-aware boundaries instead of a bare `\b`. Also makes the longhand `animation-name` + separately declared `animation-iteration-count: infinite` pattern detected consistently. Adds targeted unit tests for each fixed false-positive/false-negative. * fix(runtime): keep finite duration signal when an unbounded animation coexists getInferredDurationSeconds in the CSS and WAAPI adapters returned null outright whenever any animation on the composition was unbounded (infinite iteration count), even when other finite animations on the same composition could still supply a valid duration. This disagreed with the new root_composition_missing_duration_source lint rule, which treats any animation-name as sufficient — so a composition mixing a finite fadeIn with a decorative infinite spin passed lint but still failed at render with "zero duration". Unbounded animations are now skipped when computing the max end time instead of short-circuiting the whole calculation. null is only returned when every animation on the composition is unbounded, i.e. there is no finite signal to fall back on at all. Co-Authored-By: Claude <noreply@anthropic.com> * docs(skills): fix table separator width in data-attributes.md oxfmt flagged the merged Composition Root table from the post-rebase merge of the auto-infer-duration docs onto main's reformatted table — the separator row was one dash short of the header width. * fix(lint): keep infinite-CSS duration rule strict but make its message honest Post-review (Vance): after the finite+infinite adapter fix, the runtime infers a length for a mixed finite+infinite CSS composition, but this lint rule still (intentionally) errors on it — an unbounded animation makes the intended total length ambiguous, so we require explicit data-duration. Keep that strictness (lint is advisory by default; it only blocks under --strict, and data-duration is the one duration signal guaranteed correct across every adapter, known and future). But the message wrongly claimed the render "will fail" — false for the mixed case, where the runtime falls back to the finite animation. Rewrite it to describe the ambiguity honestly, correct the rule's block comment, and add a mixed finite+infinite test asserting it still errors with an honest message. --------- 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










