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node-addon-mpg123

node.js addon & native bindings to libmpg123

npm Build Status

node-addon-mpg123 is based on TooTallNate/node-lame and removed lame related code to keep it simple. And extended the Decoder to support decoding format options.

For all your async streaming MP3 decoding needs, there's node-addon-mpg123! This module hooks into libmpg123, the library that the mpg123 command uses, to provide Decoder streams to node.js.

Installation

node-addon-mpg123 comes bundled with its own copy of libmpg123, so there's no need to have them installed on your system.

Simply compile and install nampg123 using npm:

$ npm i nampg123

Example

Here's an example of using node-addon-mpg123 to decode an MP3 file coming from process.stdin to some raw PCM data that gets piped to process.stdout:

const mpg123 = require('nampg123');

// create the Decoder instance
const decoder = new mpg123.Decoder();

// MP3 data from stdin gets piped into the decoder
process.stdin.pipe(decoder);

// the raw PCM data gets piped to stdout
decoder.pipe(process.stdout);

See test/decoder.js for some more example code.

API

Decoder class

The Decoder class is a Stream subclass that accepts MP3 data written to it, and outputs raw PCM data. It also emits a "format" event when the format of the MP3 file is determined (usually right at the beginning). You can specify the output PCM data format when creating the decoder instance.

const mpg123 = require('nampg123');
const decoder = new mpg123.Decoder({
  sampleRate: 44100,        // [8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000]
  channels: mpg123.STEREO,  // [mpg123.MONO, mpg123.STEREO, mpg123.MONO | mpg123.STEREO]
  signed: false,            // [true, false]
  float: true,              // [true, false]
  bitDepth: 32,             // [8, 16, 24, 32]
});

⚠️ The channels option is different from the TooTallNate/node-lame encoder.

See more about mpg123 encoding formats: https://github.com/mdluo/node-addon-mpg123/blob/master/deps/mpg123/src/libmpg123/mpg123.h.in#L348-L395