<!DOCTYPE HTML> <html> <head> <title>Test the ability of MediaStream with multiple MediaStreamTracks</title> <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" /> <script type="text/javascript" src="manifest.js"></script> </head> <body> <pre id="test"> <script class="testbody" type="text/javascript"> function startTest() { navigator.mediaDevices.getUserMedia({audio:true, video:true, fake:true}) .then(function(orgStream) { var a = orgStream.getAudioTracks()[0]; var v = orgStream.getVideoTracks()[0]; var stream = new MediaStream([a, a, a, a, v, v, v].map(track => track.clone())); var element = document.createElement("video"); element.onloadedmetadata = function() { is(stream.getAudioTracks().length, 4, 'Length of audio tracks should be 4.'); is(stream.getVideoTracks().length, 3, 'Length of vudio tracks should be 3.'); SimpleTest.finish(); }; element.srcObject = stream; element.play(); }) .catch(function(reason) { ok(false, "unexpected error = " + reason.message); SimpleTest.finish(); }); } SimpleTest.waitForExplicitFinish(); SpecialPowers.pushPrefEnv( { "set": [ ["media.track.enabled", true] ] }, startTest); </script> </pre> </body> </html>