# ffmpeg.js
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Use FFmpeg directly in your browser without any backend services!!
**Transcode**
[Source Code](https://github.com/ffmpegjs/ffmpeg.js/blob/master/examples/browser/transcode.html)
## Supported Formats
- mp4 (x264)
- webm (vp8/vp9) (^0.8.0)
- mp3 (^0.8.0)
---
ffmpeg.js provides simple to use APIs, to transcode a video you only need few lines of code:
```javascript
const fs = require('fs');
const { createFFmpeg } = require('@ffmpeg/ffmpeg');
const ffmpeg = createFFmpeg({ log: true });
(async () => {
await ffmpeg.load();
await ffmpeg.write('test.avi', './test.avi');
await ffmpeg.transcode('test.avi', 'test.mp4');
fs.writeFileSync('./test.mp4', ffmpeg.read('test.mp4'));
process.exit(0);
})();
```
## Installation
```
$ npm install @ffmpeg/ffmpeg
```
> As we are using the latest experimental features, you need to add few flags to run in Node.js
```
$ node --experimental-wasm-threads --experimental-wasm-bulk-memory transcode.js
```
Or, using a script tag in the browser (only works in Chrome):
```html
```
## Multi-thread
Starting from v0.8.0, multithreading is enabled and you can use this feature by passing `-threads ` (`NUM` < 8 ). For built-in functions like `transcode()`, you can pass it as 3rd argument.
```javascript
// in transcode()
await ffmpeg.transcode('flame.avi', 'flame.mp4', '-threads 2');
// in run()
await ffmpeg.run('-i flame.avi -threads 2 flame.mp4');
```
## Examples
- With React: https://github.com/ffmpegjs/react-app
## Documentation
- [API](https://github.com/ffmpegjs/ffmpeg.js/blob/master/docs/api.md)
## Tutorials
Learn how to build ffmpeg.js from stories:
- [Part.1 Preparation](https://itnext.io/build-ffmpeg-webassembly-version-ffmpeg-js-part-1-preparation-ed12bf4c8fac)
- [Part.2 Compile with Emscripten](https://itnext.io/build-ffmpeg-webassembly-version-ffmpeg-js-part-2-compile-with-emscripten-4c581e8c9a16)
- [Part.3 ffmpeg.js v0.1.0 — Transcoding avi to mp4](https://itnext.io/build-ffmpeg-webassembly-version-ffmpeg-js-part-3-ffmpeg-js-v0-1-0-transcoding-avi-to-mp4-f729e503a397)
- [Part.4 ffmpeg.js v0.2 — Web Worker and Libx264](https://medium.com/@jeromewus/build-ffmpeg-webassembly-version-ffmpeg-js-part-4-ffmpeg-js-v0-2-web-worker-and-libx264-d0596f1beb4e)
- [Part.5 ffmpeg.js v0.3 — pre-js and live streaming](https://medium.com/@jeromewus/build-ffmpeg-webassembly-version-ffmpeg-js-part-5-ffmpeg-js-v0-3-pre-js-and-live-streaming-c1498939a74c)
- [Part.6 a Deep Dive into File System](https://medium.com/@jeromewus/build-ffmpeg-webassembly-version-ffmpeg-js-part-6-a-deep-dive-into-file-system-56eba10067ca)
- [Part.7 multithreading (WIP)]()