@unni-craftsman/aac-encode

Small WASM AAC encoder built from FAAC. It encodes PCM16 audio to AAC in an ADTS stream (.aac).

Install

npm install @unni-craftsman/aac-encode

Usage

Bun/default runtime:

import { readFileSync, writeFileSync } from 'node:fs'
import { encodeWavToAacAdts } from '@unni-craftsman/aac-encode'

const wav = readFileSync('input.wav')
const aac = await encodeWavToAacAdts(wav, { bitRate: 64000 })
writeFileSync('output.aac', aac)

Explicit Bun export:

import { encodeWavToAacAdts } from '@unni-craftsman/aac-encode/bun'

Cloudflare Workers:

import { encodeWavToAacAdts } from '@unni-craftsman/aac-encode/worker'

export default {
  async fetch(request: Request, env: { ASSETS: Fetcher }) {
    const wavResponse = await env.ASSETS.fetch(new URL('/input.wav', request.url))
    const wav = new Uint8Array(await wavResponse.arrayBuffer())
    const aac = await encodeWavToAacAdts(wav, { bitRate: 64000 })
    return new Response(aac, { headers: { 'content-type': 'audio/aac' } })
  },
}

For raw PCM:

import { encodeAacAdts } from '@unni-craftsman/aac-encode'

const aac = await encodeAacAdts(pcm16, {
  sampleRate: 24000,
  channels: 1,
  bitRate: 64000,
})

Notes

• Input must be signed 16-bit PCM.
• WAV helper supports PCM16 RIFF/WAVE files.
• Output is AAC ADTS, suitable for .aac files.
• Cloudflare Workers should import @unni-craftsman/aac-encode/worker so Wrangler uploads faac.wasm as a Wasm module.
• The bundled encoder is FAAC and is licensed LGPL-2.1-or-later.