wae-cli

web-audio-engine command line

Installation

$ npm install -g wae-cli

Usage

You can write a code using the Web Audio API via audioContext.

// coin.js
const osc = audioContext.createOscillator();
const amp = audioContext.createGain();

osc.type = "square";
osc.frequency.setValueAtTime(987.7666, 0);
osc.frequency.setValueAtTime(1318.5102, 0.075);
osc.start(0);
osc.stop(2);
osc.connect(amp);
osc.onended = () => {
  process.exit();
};

amp.gain.setValueAtTime(0.25, 0);
amp.gain.setValueAtTime(0.25, 0.075);
amp.gain.linearRampToValueAtTime(0, 2);
amp.connect(audioContext.destination);

simplest playback (using node-speaker)

$ wae coin

playback using ALSA aplay via stdout

$ wae coin -o stdout | aplay -f cd

playback using SoX play via stdout

$ wae coin -o stdout | play -t s16 -r 44100 -c 2 -

render to an audio file

$ wae coin -o coin.wav

other options

$ wae --help
wae [option] script-name [args]

  -h, --help             display help
  -v, --version          display version
  -t, --type String      file type of audio - default: s16
  -r, --rate Number      samplerate of audio - default: 44100
  -c, --channels Number  number of channels of audio: e.g. 2 = stereo - default: 2
  -d, --duration Number  number of duration for rendering
  -o, --out String       write output to <file> - default: speaker
  -V, --verbose          run in verbose mode - default: false

AUDIO FILE FORMAT: s16 s32 u8 raw cd

provide arguments

You can provide arguments from command line using node module style function. The arguments are parsed as JSON.

// beep.js
module.exports = (audioContext, frequency, duration) => {
  const osc = audioContext.createOscillator();
  const amp = audioContext.createGain();

  osc.frequency.value = frequency;
  osc.start(0);
  osc.stop(duration);
  osc.connect(amp);

  amp.gain.setValueAtTime(0.5, 0);
  amp.gain.linearRampToValueAtTime(0, duration);
  amp.connect(audioContext.destination);
};

$ wae beep -- 1760 0.5

asynchronous code

You can run asynchronous code using Promise.

const fs = require("fs");

module.exports = (audioContext) => {
  const buffer = fs.readFileSync("coin.wav");

  return audioContext.decodeAudioData(buffer).then((audioBuffer) => {
    const bufSrc = audioContext.createBufferSource();

    bufSrc.buffer = audioBuffer;
    bufSrc.start(0);

    bufSrc.connect(audioContext.destination);
  });
};

License

MIT