decode-wma

@audio/decode-wma

Decode WMA audio to PCM float samples. The package combines a pure-JS ASF demuxer with the RockBox fixed-point decoder compiled to WASM.

Install

npm i @audio/decode-wma

Usage

import decode from '@audio/decode-wma'

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

Streaming

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

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

decoder() is asynchronous. Its decode() and flush() methods are synchronous.

ASF demuxer only

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

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 a Uint8Array or ArrayBuffer chunk.
• dec.flush(): decode a buffered variable-size packet or return an empty result.
• 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

ॐ · GPL-2.0+ (RockBox)