## Problem Studio still broke down in three concrete authoring flows around timeline assets: - you could import media into Assets, but not drag an already-imported asset from the Assets tab onto the timeline and persist it into source - dragging a file from outside the app onto the timeline only uploaded it into Assets instead of placing it at the dropped time/track - once a clip was on the timeline, there was no reliable keyboard delete flow for removing it safely from source While implementing direct external drops, another real bug showed up: - valid binary uploads like `raycast.mp4` from `Downloads` were being rejected as unsupported media in Studio dev because the Vite API bridge was corrupting multipart request bodies before they reached the upload route ## What this fixes ### Timeline asset placement from inside Studio - asset cards in the Assets tab are draggable - the timeline accepts asset drops even when it already has clips - dropping an asset onto the timeline inserts a new clip into the active composition source at the dropped time / track - asset paths are rewritten relative to the target composition file so drops into sub-compositions resolve correctly - the new clip is persisted immediately and the preview refreshes ### Direct external file drops onto the timeline - dropping a file from outside the app onto the timeline now uploads it and places it onto the dropped track/time in one shot - it no longer stops halfway by only adding the file into Assets - multiple dropped files are placed using the same drop start and successive tracks ### Delete key support - selected timeline clips can now be deleted with `Delete` / `Backspace` - deletion is persisted back to source, not just removed from local state - the delete path now uses a server-side DOM mutation helper with LinkeDOM for structural safety instead of client-side string surgery ### Binary upload fix for media files - the Studio Vite API bridge now forwards non-GET request bodies as raw bytes instead of decoding them as UTF-8 text - that preserves multipart uploads for binary media like MP4s - valid local videos from `Downloads` no longer get rejected as `Unsupported media skipped` just because the dev bridge corrupted the request body - upload validation now probes buffered media through a temp file path that preserves the file extension before saving into the project ## Root cause There were really two separate gaps: ### 1. Asset placement / deletion workflow gaps The timeline and asset systems already existed, but they were disconnected: - `AssetsTab` only supported copy/import flows - `Timeline` only handled raw file import, not positioned placement for existing assets - there was no utility layer for converting a dropped asset into persisted timeline HTML - there was no structurally safe deletion path for arbitrary selected timeline clips ### 2. Binary upload corruption in Studio dev The Studio Vite API bridge rebuilt non-GET request bodies like this: - read each request chunk - call `chunk.toString()` - concatenate into a string - construct the Fetch `Request` from that string body That works for text, but it corrupts multipart binary uploads. By the time the upload route wrote the received file and ran `ffprobe`, otherwise valid MP4s had already been mangled in-flight. ## Behavior - dropping on `index.html` inserts the asset into the root composition - dropping while drilled into a composition inserts into that composition file instead - drop X position maps to `data-start` - drop Y position maps to the current visible track row, with a new bottom track created if the drop lands below existing rows - images default to a short finite duration - audio/video default to their metadata duration when available, with a fallback duration if metadata cannot be read quickly - pressing `Delete` on a selected clip removes that clip from the underlying HTML source and clears selection in Studio - valid uploaded MP4s now survive the Studio dev API bridge intact instead of being rejected during upload validation ## Verification ### Local checks - `bunx oxlint packages/core/src/studio-api/helpers/sourceMutation.ts packages/core/src/studio-api/helpers/sourceMutation.test.ts packages/core/src/studio-api/helpers/mediaValidation.ts packages/core/src/studio-api/helpers/mediaValidation.test.ts packages/core/src/studio-api/routes/files.ts packages/studio/src/App.tsx packages/studio/src/components/nle/NLELayout.tsx packages/studio/src/components/sidebar/AssetsTab.tsx packages/studio/src/player/components/Timeline.tsx packages/studio/src/player/components/Timeline.test.ts packages/studio/src/utils/timelineAssetDrop.ts packages/studio/src/utils/timelineAssetDrop.test.ts packages/studio/vite.config.ts packages/studio/vite.request-body.ts packages/studio/vite.request-body.test.ts` - `bunx oxfmt --check` on the touched files - `bun run --filter @hyperframes/core typecheck` - `bun run --filter @hyperframes/studio typecheck` - `bun test packages/core/src/studio-api/helpers/sourceMutation.test.ts packages/core/src/studio-api/helpers/mediaValidation.test.ts packages/studio/src/player/components/Timeline.test.ts packages/studio/src/utils/timelineAssetDrop.test.ts packages/studio/vite.request-body.test.ts` ### Browser / live verification Verified against a live local Studio fixture: - dragging an existing asset from the Assets tab onto the timeline creates a persisted clip at the dropped position - dropping a file from outside the app directly onto the timeline uploads it and creates a persisted clip at the dropped position - selecting a dropped clip and pressing `Delete` removes it from both the live timeline and the saved source HTML - valid MP4 uploads like `raycast.mp4` now succeed through the live Studio upload route instead of being rejected as unsupported media ## Notes - the local `timeline-trio-verify` and `timeline-overlap-debug` projects used for verification are local-only and are not part of this PR - this PR is about asset placement, upload correctness, and deletion safety; it does not broaden into richer editing workflows beyond placing/removing clips from the timeline
Write HTML. Render video. Built for agents.
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
Option 1: With an AI coding agent (recommended)
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.
For Claude Design, use the GitHub-hosted entry point at skills/claude-design-hyperframes/SKILL.md and let Claude fetch the repo's skills/ tree from there. See the Claude Design guide.
For Codex specifically, the same skills are also exposed as an OpenAI Codex plugin — sparse-install just the plugin surface:
codex plugin marketplace add heygen-com/hyperframes --sparse .codex-plugin --sparse skills --sparse assets
For Claude Code, the repo also ships a Claude Code plugin manifest: test it locally with claude --plugin-dir .. The manifest intentionally omits skills because Claude Code auto-discovers the root skills/ directory by convention, and for marketplace submission use the title HyperFrames by HeyGen plus the black/white icon assets at assets/claude-code-icon-dark.svg and assets/claude-code-icon-light.svg for the two theme slots.
For Cursor, the same skills are packaged as a Cursor plugin — install from the Cursor Marketplace, or sideload by cloning this repo and pointing Settings → Plugins → Load unpacked at the repo root.
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).
Hyperframes vs Remotion
Hyperframes is inspired by Remotion — we used Remotion at HeyGen in production, learned a ton from it, and kept attribution comments in the source for the patterns it pioneered (Chrome launch flags, image2pipe → FFmpeg streaming, frame buffering). Both tools drive headless Chrome and both are deterministic. They differ on one decision: what the primary author writes. Remotion's bet is React components; Hyperframes' bet is HTML.
| Hyperframes | Remotion | |
|---|---|---|
| Authoring | HTML + CSS + GSAP | React components (TSX) |
| Build step | None; index.html plays as-is |
Required (bundler) |
| Library-clock animations (GSAP, Anime.js, Motion One) | Seekable, frame-accurate | Plays at wall-clock during render |
| Arbitrary HTML / CSS passthrough | Paste and animate | Rewrite as JSX |
| Distributed rendering | Single-machine today | Lambda, production-ready |
Licensing: fully open source vs source-available
Hyperframes is completely open source under Apache 2.0 — an OSI-approved license. Use it commercially at any scale, with no per-render fees, no seat caps, no company-size thresholds.
Remotion is source-available, not open source. The code is on GitHub under a custom Remotion License that requires a paid company license above small-team thresholds. It's a great product with a real team behind it — but if open-source licensing matters to you (OSI compliance, redistribution rights, no per-use fees), that's a first-order decision point.
Full write-up with benchmarks, an honest list of where each tool wins, and a GSAP side-by-side: Hyperframes vs Remotion guide.
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/introduction — Quickstart | 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 |
|---|---|
claude-design-hyperframes |
Claude Design entry point that pulls the upstream skills/ tree and standardizes player-based previews |
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 |
website-to-hyperframes |
Capture a URL and turn it into a video — full website-to-video pipeline |
gsap |
GSAP animation API, timelines, easing, ScrollTrigger, plugins, React/Vue/Svelte, performance |
Contributing
See CONTRIBUTING.md for guidelines.
Cloning the repo
The repo uses Git LFS for golden regression-test baselines under packages/producer/tests/**/output.mp4 (~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
# (or install Git for Windows, which bundles Git LFS as an optional component)
# Then (once, per machine)
git lfs install
If you hit git-lfs filter-process: command not found during git clone or npx skills add heygen-com/hyperframes, install Git LFS and retry. You can also skip LFS content if you only need the source files:
GIT_LFS_SKIP_SMUDGE=1 git clone https://github.com/heygen-com/hyperframes.git
