Bug 198284 – Web Audio fed into local <video> via MediaStreamAudioDestinationNode does not play on Mac

• Component: Web Audio
• Status: NEW

[Brooke Vibber]

Web Audio such as an oscillator or script processor node piped into a local <video> through MediaStraemAudioDestinationNode doesn't play in Safari on Mac, but does work on iOS and the iOS Simulator.

Tested Safari 12.1.1 and Technology Preview on macOS 10.14 and 10.13 (no audio), while it works on iOS 12.4.1 and the iOS 12.2 Simulator tested locally.


Test case:

https://jsfiddle.net/0uLg4j3w/

----------
<div>
  <button id=start>Start</button>
<div>
  <video id=sink playsinline controls width=320 height=240></video>
</div>
----------
start.addEventListener('click', function() {
  start.disabled = true;
	var context = new (window.AudioContext || window.webkitAudioContext)();
  var dest = context.createMediaStreamDestination();
  var src = context.createOscillator();
  src.connect(dest);
  src.start();
  sink.srcObject = dest.stream;
  sink.play();
});
----------


Expected results: tone plays
Actual results: no tone plays

[Radar WebKit Bug Importer]

<rdar://problem/51290997>

I've found this behaviour in iTunes 12.9.5 while playing local media as well as streaming iTunes extras, and webkit based browsers to bluetooth speakers.