@mediabunny/aac-encoder

Some browsers lack support for AAC encoding in their WebCodecs implementations. This extension package provides a reliable AAC-LC encoder for use with Mediabunny. It is implemented using Mediabunny's custom coder API and uses a fast, size-optimized WASM build of FFmpeg's AAC encoder under the hood.

GitHub page

Installation

This library peer-depends on Mediabunny. Install both using npm:

npm install mediabunny @mediabunny/aac-encoder

Alternatively, directly include them using a script tag:

<script src="mediabunny.js"></script>
<script src="mediabunny-aac-encoder.js"></script>

This will expose the global objects Mediabunny and MediabunnyAacEncoder. Use mediabunny-aac-encoder.d.ts to provide types for these globals. You can download the built distribution files from the releases page.

Usage

import { registerAacEncoder } from '@mediabunny/aac-encoder';

registerAacEncoder();

That's it - Mediabunny now uses the registered AAC encoder automatically.

If you want to be more correct, check for native browser support first:

import { canEncodeAudio } from 'mediabunny';
import { registerAacEncoder } from '@mediabunny/aac-encoder';

if (!(await canEncodeAudio('aac'))) {
    registerAacEncoder();
}

Example

Here, we convert an input file to an MP4 with AAC audio:

import {
    Input,
    ALL_FORMATS,
    BlobSource,
    Output,
    BufferTarget,
    Mp4OutputFormat,
    canEncodeAudio,
    Conversion,
} from 'mediabunny';
import { registerAacEncoder } from '@mediabunny/aac-encoder';

if (!(await canEncodeAudio('aac'))) {
    // Only register the custom encoder if there's no native support
    registerAacEncoder();
}

const input = new Input({
    source: new BlobSource(file), // From a file picker, for example
    formats: ALL_FORMATS,
});
const output = new Output({
    format: new Mp4OutputFormat(),
    target: new BufferTarget(),
});

const conversion = await Conversion.init({
    input,
    output,
});
await conversion.execute();

output.target.buffer; // => ArrayBuffer containing the MP4 file