Media Source Extension support with WebAudio AudioContext

Number:rdar://37084774 Date Originated:2018-01-31
Status:Open Resolved:
Product:Safari Product Version:11.0.3
Classification: Reproducible:Yes
Based on the Web Audio and Media Source Extension specifications, it should be possible to connect an AudioNode to a MediaStreamDestination and, in turn, specify the stream property of that destination as the srcObject for an Audio element. This process works successfully in Blink/Chrome.

Steps to Reproduce:
<audio id="a" controls>
<script type="module">
  const context = new webkitAudioContext();
  const destination = context.createMediaStreamDestination();

  const audioElement = document.getElementById('a');
  audioElement.srcObject =;

  // trigger events on AudioNodes connected to destination

Expected Results:
Audio should play as if nodes were connected to the context destination, but controlled via the Audio element.

Actual Results:
Safari shows an audio playback state in the status bar, but no audio is ever heard. Auto play audio blocks are disabled.

Safari 11.0.3 (12604.
Safari Technology Preview 11.2 Release 48 (12606.1.2.2)


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