https://github.com/openclaw/ffmpeg-wasm
Lightweight FFmpeg and FFprobe for Node, built as modern WebAssembly for local media automation.
https://github.com/openclaw/ffmpeg-wasm
Last synced: about 1 month ago
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Lightweight FFmpeg and FFprobe for Node, built as modern WebAssembly for local media automation.
- Host: GitHub
- URL: https://github.com/openclaw/ffmpeg-wasm
- Owner: openclaw
- License: mit
- Created: 2026-06-06T22:08:07.000Z (about 1 month ago)
- Default Branch: main
- Last Pushed: 2026-06-12T01:11:02.000Z (about 1 month ago)
- Last Synced: 2026-06-12T03:15:05.347Z (about 1 month ago)
- Language: JavaScript
- Homepage:
- Size: 785 KB
- Stars: 28
- Watchers: 0
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# ffmpeg-wasm local
[](https://github.com/openclaw/ffmpeg-wasm/actions/workflows/ci.yml)
Lightweight FFmpeg and FFprobe for Node, built as modern WebAssembly for local media automation.
This repository is intentionally small in scope: one reproducible Emscripten build, one TypeScript wrapper, and enough codecs/protocols for media inspection, audio extraction, thumbnails, pipe I/O, and segmentation.
## Why
Many media workflows need predictable FFmpeg and FFprobe behavior without carrying a full native FFmpeg bundle. This package builds a narrow LGPL FFmpeg wasm core and exposes it through:
- `ffmpeg-wasm`, a CLI-compatible FFmpeg entrypoint.
- `ffprobe-wasm`, a CLI-compatible FFprobe entrypoint.
- TypeScript APIs for binary-safe buffered or streaming execution.
## License
The wrapper, scripts, and documentation in this repository are MIT licensed.
Generated FFmpeg assets in `dist/` are copied from FFmpeg and are LGPL-2.1-or-later. Linked libvpx code is BSD-licensed. The build does not pass `--enable-gpl` or `--enable-nonfree`. FFmpeg and libvpx license files are copied into `dist/` during `pnpm build`.
Keep wrapper code and generated FFmpeg binaries conceptually separate when this moves under OpenClaw packaging. A downstream package can stay MIT for the wrapper while distributing the FFmpeg wasm artifacts under the LGPL terms that apply to FFmpeg.
## Build Surface
Default refs:
- FFmpeg: `n8.1.1`
- LAME: `master` from `ffmpegwasm/lame`
- libvpx: `v1.16.0`
- Runtime: Node 24+
- Compiler: Emscripten via `emcc`
Enabled programs:
- `ffmpeg`
- `ffprobe`
Enabled protocols:
- `data`
- `fd`
- `file`
- `pipe`
Enabled demuxers:
- `aac`
- `flac`
- `hls`
- `image2`
- `matroska`
- `mov`
- `mp3`
- `mpegts`
- `ogg`
- `wav`
Enabled muxers:
- `image2`
- `mov`
- `mp4`
- `mp3`
- `null`
- `rawvideo`
- `segment`
- `wav`
- `webm`
Enabled decoders:
- `aac`
- `flac`
- `h263`
- `h264`
- `hevc`
- `mpeg4`
- `mjpeg`
- `mp3`
- `opus`
- `pcm_s16le`
- `png`
- `vorbis`
- `vp8`
- `vp9`
- `wrapped_avframe`
Enabled encoders:
- `h263`
- `libmp3lame`
- `libvpx` (VP8)
- `mpeg4`
- `opus`
- `pcm_s16le`
- `png`
- `rawvideo`
- `wrapped_avframe`
Enabled filters:
- `aformat`
- `aresample`
- `format`
- `metadata`
- `null`
- `scale`
- `select`
- `showinfo`
- `signalstats`
External libraries:
- `libmp3lame`
- `libvpx`
- `zlib`
Each generated Node or browser FFmpeg/FFprobe bundle is about 8.5 MB on current builds.
## Install
```sh
pnpm install
```
Required system tools for a full wasm build:
- Emscripten SDK with `emcc`, `em++`, `emar`, and `emranlib` on `PATH`
- Autotools for LAME
- `make`, `pkg-config`, `nasm`, `yasm`
On macOS:
```sh
brew install autoconf automake libtool nasm pkg-config yasm
```
## Commands
```sh
pnpm build
pnpm docs:build
pnpm playground
pnpm playground:e2e
pnpm verify
pnpm test:e2e
pnpm check
```
`pnpm build` compiles TypeScript, fetches the configured FFmpeg/LAME/libvpx refs into `.cache/`, builds static LAME and libvpx, builds FFmpeg/FFprobe wasm, and writes generated assets to `dist/`.
`pnpm docs:build` builds the static site into `dist/docs-site`: the media workbench at `/`, its compiled TypeScript client and browser ffmpac worker, the browser wasm bundle, and documentation under `/docs/`.
`pnpm playground` starts a local one-page media bench at `http://127.0.0.1:4173`. It lets you load a video, choose a supported preset, inspect the generated FFmpeg args, render through the wasm wrapper, preview the output inline, and save via the browser file picker or download fallback.
`pnpm playground:e2e` starts the playground on a temporary port, launches Chrome through DevTools, loads the sample video, renders a smaller MP4 and an MP3, and writes `.tmp/playground-e2e-server.png` for visual proof. Set `PLAYGROUND_E2E_STATIC=1` to test the static `dist/docs-site` workbench with `/api/*` blocked and only browser ffmpac available; that mode writes `.tmp/playground-e2e-static.png`.
`pnpm verify` creates a tiny test video through the wasm build with external executable lookup disabled, then exercises FFprobe text and JSON output, API and CLI MP4/MP3 conversions, codec and dimension assertions, stdin pipe input, stdout pipe output, PNG frame output, rawvideo byte equality, segmentation, cwd/dist overrides, API validation failures, and CLI failure paths. Set `FFMPEG_WASM_VERIFY_OUTPUT_DIR` to retain the converted files and JSON manifest.
`pnpm test:e2e` rebuilds the wasm assets from source, then runs the same live verifier against the generated FFmpeg/FFprobe wrappers.
`pnpm check` runs `tsgo`, strict `oxlint`, and `oxfmt --check`.
## CLI
After `pnpm build`, use the compiled entrypoints directly:
```sh
node lib/src/ffprobe-cli.js -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 input.mp4
node lib/src/cli.js -hide_banner -loglevel error -i input.mp4 -vn -ac 1 -ar 16000 audio.wav
node lib/src/ffprobe-cli.js -v error -show_format input.mp4
node lib/src/cli.js -hide_banner -i input.mp4 -frames:v 1 frame.png
node lib/src/cli.js -hide_banner -ss 0 -i input.mp4 -t 5 -map 0:v:0 -map 0:a? -c copy -movflags +faststart clip.mp4
```
The package also declares `ffmpeg-wasm` and `ffprobe-wasm` bin entries for downstream package-manager linking.
## TypeScript API
```ts
import { execFfmpeg, runFfmpeg, runFfprobe } from "@steipete/ffmpeg-wasm-local";
const probe = await runFfprobe([
"-v",
"error",
"-show_entries",
"format=duration",
"-of",
"default=noprint_wrappers=1:nokey=1",
"input.mp4",
]);
if (probe.exitCode !== 0) throw new Error(probe.stderrText);
const wav = await runFfmpeg([
"-hide_banner",
"-loglevel",
"error",
"-i",
"input.mp4",
"-vn",
"-ac",
"1",
"-ar",
"16000",
"-f",
"wav",
"-",
]);
await execFfmpeg(["-hide_banner", "-i", "input.mp4", "audio.mp3"]);
```
`runFfmpeg` and `runFfprobe` buffer stdout/stderr and return `Buffer` fields plus UTF-8 text helpers. Use these for probes, small generated files, and tests.
`execFfmpeg` and `execFfprobe` stream stdio and return only the exit code. Use these for CLI-style work or larger outputs.
Both APIs accept:
- `distDir` to point at a custom generated asset directory.
- `cwd` and `env` for process isolation.
- `stdin` for pipe input.
- `timeoutMs` for opt-in time limits.
`ffmpeg` receives `-nostdin` automatically unless the caller already supplied it. Explicit `-i -` stdin input still works through the wrapper.
## Downstream Wiring
Build once:
```sh
pnpm build
```
Then point a downstream tool at the compiled wrappers:
```sh
FFMPEG_PATH="$PWD/lib/src/cli.js" \
FFPROBE_PATH="$PWD/lib/src/ffprobe-cli.js" \
your-tool ...
```
For direct package usage, import the TypeScript API and keep `dist/` next to the compiled `lib/` tree.
## Build Tuning
Override source refs per build:
```sh
FFMPEG_VERSION=n8.1.1 LAME_REF=master LIBVPX_REF=v1.16.0 pnpm build
```
To keep the binary small, only add codecs, demuxers, muxers, filters, or protocols when a real caller needs them. Prefer adding one capability and extending `scripts/verify.ts` with a matching proof.
Useful places:
- `playground/`: one-page local editor assets, TypeScript client, and browser ffmpac worker.
- `docs/`: Cloudflare Pages source docs and screenshot assets.
- `scripts/build.ts`: configure flags and Emscripten linker flags.
- `scripts/build-docs-site.ts`: static docs site builder.
- `scripts/playground-server.ts`: local editor server and render endpoints.
- `scripts/verify.ts`: behavioral coverage for the generated wasm.
- `.oxlintrc.json`: strict lint policy.
## CI
GitHub Actions runs two jobs:
- TypeScript, lint, and format on Node 24.
- Static docs site build.
- Full live wasm E2E with Emscripten, explicit API and CLI media conversions, codec/dimension assertions, native executable auditing, server and static browser workbench tests, build caching, and proof artifact uploads.
CI intentionally builds from source instead of trusting checked-in wasm output. `dist/` is ignored and regenerated. The wasm job uploads `dist/`, converted media, a verification manifest, and both browser screenshots for inspection.