@audio/decode

Decode any audio format to raw samples.
JS / WASM – no ffmpeg, no native bindings, works in both node and browser.
Small API, minimal size, near-native performance, lazy-loading, chunked decoding.

import decode from '@audio/decode';

const { channelData, sampleRate } = await decode(anyAudioBuffer);

Supported formats

Format	Package	Size	Engine
MP3	@audio/decode-mp3	92 KB	WASM
WAV	@audio/decode-wav	4 KB	JS
OGG Vorbis	@audio/decode-vorbis	164 KB	WASM
FLAC	@audio/decode-flac	133 KB	WASM
Opus	@audio/decode-opus	178 KB	WASM
M4A / AAC / ALAC	@audio/decode-aac	368 KB	WASM + JS
QOA	@audio/decode-qoa	8 KB	JS
AIFF	@audio/decode-aiff	20 KB	JS
CAF	@audio/decode-caf	7 KB	JS
WebM	@audio/decode-webm	263 KB	WASM
AMR	@audio/decode-amr	241 KB	WASM
WMA	@audio/decode-wma	91 KB	WASM

Whole-file

Auto-detects format. Input can be ArrayBuffer, Uint8Array, Buffer, or anything that materializes to bytes — a Blob/File (browser file input, drag-drop) or a fetch Response.

import decode from '@audio/decode'

let { channelData, sampleRate } = await decode(buf)
let fromFile = await decode(fileInput.files[0])   // File
let fromUrl  = await decode(await fetch(url))      // Response

Chunked

let dec = await decode.mp3()
let a = await dec(chunk1)    // { channelData, sampleRate }
let b = await dec(chunk2)
await dec()                  // close

Streaming

import decode from '@audio/decode'

for await (let { channelData, sampleRate } of decode.mp3(response.body)) {
  // process chunks
}

Works with ReadableStream, fetch body, Node stream, or any async iterable.

Formats: mp3, flac, opus, oga, m4a, wav, qoa, aac, aiff, caf, webm, amr, wma.

Browser

Works from CDN without a bundler – codecs load on demand via dynamic import, only for formats you actually decode:

<script type="module">
  import decode from 'https://esm.sh/@audio/decode'
  let { channelData, sampleRate } = await decode(buf)
</script>

Self-hosting instead of a CDN? Use an import map to point @audio/decode and each @audio/decode-* package you need to its local path – every codec is a self-contained bundle (WASM inlined, no transitive deps).

Metadata

Read tags, pictures, markers and regions without decoding samples. Available for wav, mp3, flac, oga (Ogg Vorbis), opus, and m4a.

import { wav, mp3, flac, oga, opus, m4a } from '@audio/decode/meta'

let { meta, sampleRate, markers, regions } = mp3(bytes)
// meta: { title, artist, album, year, bpm, key, comment, pictures, raw, ... }
// markers: [{ sample, label }]
// regions: [{ sample, length, label }]

Each codec sub-package also exposes its parser directly:

import { parseMeta } from '@audio/decode-wav/meta'
let info = parseMeta(wavBytes)

WebWorker

Each @audio/decode-* package is a self-contained ESM module — import directly in a worker:

// decode-worker.js
import decode from '@audio/decode-mp3'

self.onmessage = async ({ data }) => {
  let pcm = await decode(data)
  self.postMessage(pcm, pcm.channelData.map(ch => ch.buffer))
}

// main.js
let worker = new Worker('./decode-worker.js', { type: 'module' })
worker.postMessage(mp3buf, [mp3buf])
worker.onmessage = ({ data }) => { /* { channelData, sampleRate } */ }

See also

• encode – encode PCM into any audio format.
• audio-type – detect audio format from buffer.

Licensing: the umbrella and most codec atoms are MIT; three atoms inherit their upstream codec implementation's license — @audio/decode-aac GPL-2.0, @audio/decode-wma GPL-2.0-or-later, @audio/decode-amr Apache-2.0. Install only the codecs whose licenses fit your project — the umbrella loads them on demand.

MIT • ॐ