README

ima-adpcm-decoder

AudioContext Decoder for ADPCM-Wavefiles

Installation

npm install ima-adpcm-decoder

yarn add ima-adpcm-decoder

Usage

import { decodeImaAdpcm } from 'ima-adpcm-decoder';

const playAdpcm = async () => {
    const ctx = new AudioContext();

    const response = await fetch('./test.wav');
    const buffer = await response.arrayBuffer();
    const audioBuffer = decodeImaAdpcm(ctx, buffer);

    const src = ctx.createBufferSource();
    src.buffer = audioBuffer;
    src.connect(ctx.destination);
    src.start(0);
};

For streaming, the package also exposes the decodeImaAdpcmBlock function, which decodes a single block of ADPCM samples.

Notes

As this uses the AudioContext directly, this currently only works in Browsers. A future implementation may use webasm to provide async decoding of ADPCM Buffers.

This code runs synchronously in the Browser, meaning it will block the event-loop until the decoding is finished. That may take some time depending on the size of your Wavefiles.

This package correctly handles multi-channel wavefiles.

Do not use if...

You need decoding of ADPCM files in nodejs
You need async decoding
You are not okay with the hefty dependency that is wavefile

Dependencies (1)

wavefile - used for parsing wavefiles

Thanks

The code for decoding ADPCM-blocks is ported from ADPCM-XQ

This code draws inspiration from imaadpcm

So thanks go to David Bryant and Rafael da Silva Rocha.

Usage no npm install needed!