node-webcodecs

WebCodecs API for Node.js — encode and decode video/audio with browser-compatible APIs, powered by FFmpeg.


Why node-webcodecs?

| Feature | node-webcodecs | Browser WebCodecs |
| -------------------- | --------------------------- | ----------------- |
| Video Codecs | H.264, H.265, VP8, VP9, AV1 | Varies by browser |
| Audio Codecs | AAC, Opus, MP3, FLAC | Varies by browser |
| Container Muxing | MP4 | Not in spec |
| Demuxing | Any FFmpeg format | Not in spec |
| Server-side | Yes | Browser only |

Installation

``bash
npm install @pproenca/node-webcodecs
`

Prebuilt binaries with FFmpeg statically linked are included for:

- macOS ARM64 (Apple Silicon)
- macOS x64 (Intel)
- Linux x64 (musl, fully static)

Quick Start

$3

`javascript
import { VideoEncoder, VideoFrame } from "@pproenca/node-webcodecs";

const encoder = new VideoEncoder({
output: (chunk) => chunks.push(chunk),
error: console.error,
});

encoder.configure({
codec: "avc1.42001e",
width: 1920,
height: 1080,
bitrate: 5_000_000,
});

const frame = new VideoFrame(rgbaBuffer, {
format: "RGBA",
codedWidth: 1920,
codedHeight: 1080,
timestamp: 0,
});

encoder.encode(frame);
frame.close();
await encoder.flush();
`

$3

`javascript
import { VideoDecoder, EncodedVideoChunk } from "@pproenca/node-webcodecs";

const decoder = new VideoDecoder({
output: (frame) => {
// Process frame...
frame.close();
},
error: console.error,
});

decoder.configure({
codec: "avc1.42001e",
codedWidth: 1920,
codedHeight: 1080,
});

decoder.decode(new EncodedVideoChunk({ type: "key", timestamp: 0, data }));
await decoder.flush();
`

$3

`javascript
import { Muxer } from "@pproenca/node-webcodecs";

const muxer = new Muxer({ filename: "output.mp4" });

muxer.addVideoTrack({
codec: "avc1.42001e",
width: 1920,
height: 1080,
description: codecDescription,
});

muxer.writeVideoChunk(chunk);
muxer.finalize();
`

$3

`javascript
import { Demuxer } from "@pproenca/node-webcodecs";

const demuxer = new Demuxer({
onTrack: (track) => console.log(track.codec),
onChunk: (chunk, trackIndex) => decoder.decode(chunk),
onError: console.error,
});

demuxer.open("input.mp4");
demuxer.demux();
demuxer.close();
`

See examples/ for complete working code.

API

This library implements the W3C WebCodecs specification.

| Class | Description |
| ----------------------------------------- | ------------------------------- |
| VideoEncoder / VideoDecoder | Compress / decompress video |
| AudioEncoder / AudioDecoder | Compress / decompress audio |
| VideoFrame / AudioData | Raw media containers |
| EncodedVideoChunk / EncodedAudioChunk | Compressed media packets |
| ImageDecoder | Decode JPEG, PNG, WebP, GIF |
| | |
| Muxer / Demuxer` | Container I/O (beyond W3C spec) |

Video codecs: H.264, H.265, VP8, VP9, AV1
Audio codecs: AAC, Opus, MP3 (decode), FLAC (decode)

See docs/codecs.md for codec strings and pixel formats.

Contributing

See CONTRIBUTING.md.

License

MIT