wma-decode

Decode WMA audio to PCM float samples. ASF demuxer in pure JS, WMA decoding via RockBox fixed-point decoder compiled to WASM (70 KB).

Part of audio-decode.

Install

npm i @audio/wma-decode

Usage

import decode from '@audio/wma-decode'

let { channelData, sampleRate } = await decode(wmaBuffer)

Streaming

import { decoder } from '@audio/wma-decode'

let dec = await decoder()
let result = dec.decode(chunk)
dec.free()

ASF demuxer only

import { demuxASF } from '@audio/wma-decode'

let { channels, sampleRate, bitRate, packets } = demuxASF(buffer)

API

decode(src): Promise<AudioData>

Whole-file decode. Accepts Uint8Array or ArrayBuffer.

decoder(): Promise<WMADecoder>

Creates a decoder instance.

• dec.decode(data) — decode chunk, returns { channelData, sampleRate }
• dec.flush() — flush (returns empty)
• dec.free() — release WASM memory

demuxASF(buf): ASFInfo

Parse ASF container without decoding. Returns stream properties and raw packets.

Formats

• WMA v1 (0x0160)
• WMA v2 (0x0161)

WMA Pro and Lossless are not supported. An FFmpeg-based build is available via build-ffmpeg.sh for those formats.

Building WASM

npm run build

RockBox source is included in lib/rockbox-wma/ (3 files, 152 KB).

License

GPL-2.0+ (RockBox)

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