Choose your target

Every alpha2 package renders the same project document with the same rendering code. They differ in where they run and in who decodes and encodes the media. Use this page to pick one.

At a glance

Package	Runs in	Decodes media	Encodes files	Renders on
alpha2	Browser (WebAssembly)	Your app (helpers: WebCodecs, mediabunny)	Your app (helpers: WebCodecs, mediabunny)	WebGPU, else WebGL2, else the CPU renderer
@alpha2-sh/react	Browser, React 18 or later	As alpha2	As alpha2	As alpha2
@alpha2-sh/editor	Browser; its editing core also in Node.js	Its browser bridge imports files	Its browser bridge exports through WebCodecs	As alpha2
@alpha2-sh/node	Node.js, Electron main process	alpha2-host (FFmpeg 8)	alpha2-host (FFmpeg 8)	GPU, or the CPU renderer
alpha2-host	Command line, or any language over stdio	FFmpeg 8	FFmpeg 8	GPU, or the CPU renderer
alpha2 (Python)	Python 3.11.4 or later	alpha2-host	alpha2-host	GPU, or the CPU renderer
alpha2 (crate)	Your Rust program	Your program (or alpha2-native)	Your program (or alpha2-native)	wgpu: Direct3D 12 on Windows, Metal on macOS, Vulkan (then GL) on Linux

Browser: alpha2

Choose it when you preview or export in the browser and want control over every step. The package is the engine as WebAssembly plus the TypeScript that drives it.

• Does: load and validate projects, render a time on a canvas, export offscreen on the exact frame grid (planar I420 frames), mix audio, measure loudness, lay out text.
• Doesn’t: open files. Your app decodes media and uploads frames and audio, and encodes the export. alpha2/frame-supply, alpha2/media and the optional alpha2/mediabunny (decoders, and an MP4, MOV, MKV and WebM sink) do most of that work for you.

React: @alpha2-sh/react

Choose it to show the alpha2 player in a React tree. Alpha2Canvas makes the canvas, hands it to a player you create, presents timeTicks when it changes and recovers from a lost GPU onto a new canvas. You still supply the player and the frames.

Editor: @alpha2-sh/editor

Choose it when you build an editing app. Its core holds documents, typed commands, validation and undo, and runs without a DOM, so it also works in Node.js. Its browser bridge imports files, previews, plays with audio and exports to MP4, MOV, MKV or WebM through WebCodecs. @alpha2-sh/editor/react adds React bindings (React 19.3 or a later 19).

Node.js and Electron: @alpha2-sh/node

Choose it to export files on a server or from an Electron main process. It runs alpha2-host, the native renderer, one process per export. The host decodes and encodes with FFmpeg 8 (MP4 with H.264 and AAC by default; MOV, Matroska and WebM too) and renders on a hardware GPU, or on the CPU when there is none. npx @alpha2-sh/node install fetches the host for your platform.

• Does: export files, render stills to PNG, report capabilities, check media before rendering (conform).
• Doesn’t: preview interactively. For that, pair it with the browser packages.

Any other language: alpha2-host

Choose it from a shell script, or from a language without a client. alpha2-host export exports one project from the command line. alpha2-host serve takes JSON requests on standard input and answers on standard output: the host protocol. The archives also contain alpha2, a media command that probes, transcodes and thumbnails files.

Python: alpha2

Choose it to build, validate and export projects from Python. Projects are plain dicts, validation runs the engine’s own validator in-process, and rendering runs alpha2-host. It adds authoring helpers, a text measurer and alpha2.compose, which compiles a video described by intent (slideshows, titles, captions, music) into a project.

Rust: the alpha2 crate

Choose it to embed the engine in a Rust program. You lend the engine decoded frames through a FrameProvider and take back rendered frames and YUV 4:2:0 planes. The crate does not read or write media files; alpha2-native decodes, probes and encodes with FFmpeg 8 if you need it. The wgpu-interop feature shares your own wgpu device and textures with the engine.

Extensions

SVG, animated images (GIF, animated WebP, APNG), Lottie, OpenEXR and image sequences are read by extension providers. alpha2-host reads them natively, and the browser loads the same code from its own WebAssembly module only when a project opens such a source. See Extensions.

Platforms

Platform	GPU	Hardware decode and encode
Browser	WebGPU; WebGL2 when drawing on a canvas without WebGPU	by the application
Linux x64, arm64 (glibc 2.35 or later; not musl)	Vulkan	Vulkan Video
macOS (Apple silicon)	Metal	VideoToolbox
Windows x64	Direct3D 12	D3D12VA

Windows on ARM is not supported. Minimum runtimes: Node.js 22.21 or later (24.5 or later on Node 24), Python 3.11.4, Rust 1.88.

Note

A runtime WGSL effect needs a GPU. The CPU renderer draws every built-in effect and transition, but refuses a runtime effect with EFFECT_ERROR.

Next

Browser supportWhat a browser needs to run the engine.

Your first renderBuild a project and run it on each target.

DeterminismWhat the same project gives on different targets.