Не работает ScriptProcessorNode с OfflineContext

console.clear(); 
var playButton = document.querySelector('.play'); 
var playButtonOffline = document.querySelector('.play-offline'); 
 
var current = 0; 
var buffer_size = 4096; 
var buffer_length = buffer_size * 10; 
 
 
var audioCtx = new(window.AudioContext || window.webkitAudioContext)(); 
var scriptNode = audioCtx.createScriptProcessor(buffer_size, 1, 1); 
scriptNode.onaudioprocess = whiteNoise; 
 
 
function whiteNoise(audioProcessingEvent) { 
  console.log('onaudioprocess', current); 
 
  // The output buffer contains the samples that will be modified and played 
  var outputBuffer = audioProcessingEvent.outputBuffer; 
 
  // Loop through the output channel 
  for (var channel = 0; channel < outputBuffer.numberOfChannels; channel++) { 
    var outputData = outputBuffer.getChannelData(channel); 
    for (var sample = 0; sample < buffer_size; sample++) { 
      // add noise to each output sample 
      outputData[sample] += ((Math.random() * 2) - 1); 
    } 
  } 
  current += buffer_size; 
  if (current > buffer_length) 
    scriptNode.disconnect(); 
} 
 
playButton.onclick = function() { 
  current = 0; 
  scriptNode.connect(audioCtx.destination); 
} 
 
playButtonOffline.onclick = function() { 
  var offlineCtx = new(window.OfflineAudioContext || window.webkitOfflineAudioContext)(1, buffer_length, 48000); 
  var scriptNodeOffline = offlineCtx.createScriptProcessor(buffer_size, 1, 1); 
  scriptNodeOffline.onaudioprocess = whiteNoise; 
  current = 0; 
  offlineCtx.oncomplete = function(e) { 
    console.log('rendered buffer', e.renderedBuffer.getChannelData(0).filter(f => f != 0).length); 
  } 
  scriptNodeOffline.connect(offlineCtx.destination); 
  offlineCtx.startRendering(); 
}

<button class="play"> 
  play 
</button> 
<button class="play-offline"> 
  Render offline 
</button>

// Create AudioContext and buffer source 
console.clear(); 
 
var playButton = document.querySelector('.play'); 
var playButtonOffline = document.querySelector('.play-offline'); 
var myBuffer = null; 
 
var audioCtx = new(window.AudioContext || window.webkitAudioContext)(); 
var source = audioCtx.createBufferSource(); 
 
// Create a ScriptProcessorNode with a bufferSize of 4096 and a single input and output channel 
var scriptNode = audioCtx.createScriptProcessor(4096, 1, 1); 
 
// load in an audio track via XHR and decodeAudioData 
 
function getData() { 
  request = new XMLHttpRequest(); 
  request.open('GET', 'https://s3-ap-northeast-1.amazonaws.com/storage.cowrite.decodeapps.io/Materials/Media/Audio/59f2b85dd3aed-20171027-043853.mp3', true); 
  request.responseType = 'arraybuffer'; 
  request.onload = function() { 
    var audioData = request.response; 
 
    audioCtx.decodeAudioData(audioData, function(buffer) { 
        myBuffer = buffer; 
        source.buffer = myBuffer; 
      }, 
      function(e) { 
        "Error with decoding audio data" + e.err 
      }); 
  } 
  request.send(); 
} 
 
function addNoise(audioProcessingEvent) { 
  console.log("onaudioprocess") 
  // The input buffer is the song we loaded earlier 
  var inputBuffer = audioProcessingEvent.inputBuffer; 
 
  // The output buffer contains the samples that will be modified and played 
  var outputBuffer = audioProcessingEvent.outputBuffer; 
 
  // Loop through the output channels (in this case there is only one) 
  for (var channel = 0; channel < outputBuffer.numberOfChannels; channel++) { 
    var inputData = inputBuffer.getChannelData(channel); 
    var outputData = outputBuffer.getChannelData(channel); 
 
    // Loop through the 4096 samples 
    for (var sample = 0; sample < inputBuffer.length; sample++) { 
      // make output equal to the same as the input 
      outputData[sample] = inputData[sample]; 
 
      // add noise to each output sample 
      outputData[sample] += ((Math.random() * 2) - 1) * 0.2; 
    } 
  } 
} 
 
// Give the node a function to process audio events 
scriptNode.onaudioprocess = addNoise; 
 
getData(); 
 
// wire up play button 
playButton.onclick = function() { 
  source.connect(scriptNode); 
  scriptNode.connect(audioCtx.destination); 
  source.start(); 
} 
 
// When the buffer source stops playing, disconnect everything 
source.onended = function() { 
  source.disconnect(scriptNode); 
  scriptNode.disconnect(audioCtx.destination); 
} 
 
 
// When the buffer source stops playing, disconnect everything 
 
 
// wire up play button 
playButtonOffline.onclick = function() { 
  var offlineCtx = new(window.OfflineAudioContext || window.webkitOfflineAudioContext)(2, 44100 * 40, 44100); 
  var scriptNodeOffline = offlineCtx.createScriptProcessor(4096, 1, 1); 
  var sourceOffline = offlineCtx.createBufferSource(); 
  sourceOffline.buffer = myBuffer; 
  sourceOffline.onended = function() { 
    console.log('sourceOffline.onended'); 
    sourceOffline.disconnect(scriptNodeOffline); 
    scriptNodeOffline.disconnect(offlineCtx.destination); 
  } 
  scriptNodeOffline.onaudioprocess = addNoise; 
  sourceOffline.connect(scriptNodeOffline); 
  scriptNodeOffline.connect(offlineCtx.destination); 
  sourceOffline.start(); 
  offlineCtx.oncomplete = function(e) { 
    console.log('renderedBuffer', e.renderedBuffer.getChannelData(0).filter(f => f != 0).length); 
  }; 
  offlineCtx.startRendering(); 
}

<button class="play"> 
  play 
</button> 
<button class="play-offline"> 
  Render offline 
</button>