audio-timeline

Observ object for arranging, trimming and adjusting multiple audio clips on a timeline using Web Audio.

Example

var Timeline = require('audio-timeline')
var audioContext = new window.AudioContext() // Web Audio

var context = {
  audio: audioContext,
  output: audioContext.destination,
  fs: require('fs'),
  cwd: __dirname,
  nodes: {
    clip: require('audio-timeline/clip')
  }
}

var timeline = Timeline(context)
timeline.set({
  primary: [
    { node: 'clip',
      src: 'audio/raw.wav',
      startOffset: 0,
      duration: 25
    },
    { node: 'clip',
      src: 'audio/raw.wav',
      startOffset: 500,
      duration: 30
    },
    { node: 'clip',
      src: 'audio/raw.wav',
      startOffset: 1000,
      duration: 16
    }
  ]
})

Playback

var startAt = audioContext.currentTime + 0.1
var startOffset = 0
var duration = 71

timeline.start(startAt, startOffset, duration)

Render to disk

var RenderStream = require('audio-timeline/render-stream')
var WaveFileWriter = require('wav').FileWriter

var startOffset = 0
var duration = 71
var bitDepth = 16

var stream = RenderStream(timeline, startOffset, duration, bitDepth)

stream.pipe(WaveFileWriter('output.wav', {
  bitDepth: bitDepth,
  sampleRate: audioContext.sampleRate,
  channels: 2
})).on('finish', function() {
  console.log('done')
})

stream.progress(function(value) {
  console.log(Math.round(value*100))
})