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My Need
html5 video element loads both a video and a vtt file saved in a different domain.
The problem
vtt is not loaded and error Text track from origin has been blocked from loading: Not at same origin as the document, and parent of track element does not have a 'crossorigin' attribute.
My investigation
I am aware that CORS needs to be used so vtt can be loaded in html5 successfully.
I have enabled CORS on server side for requests from any domain.
Some articles say adding crossorigin or crossorigin="anonymous" into ` element can do the job, but it doesn't work. Either the video is not loaded at all or different errors appear
I have put my code here below
<body>
<div class="container">
<video id="myvideo" controls preload="auto" width="640" height="264" autoplay>
<source src=http://video.dublearn.net/-KqIgE-3roMSBbiHUmLI/video.mp4 type="video/mp4"></source>
<track kind="captions" label="English" srclang="en" src=http://video.dublearn.net/-KqIgE-3roMSBbiHUmLI/video.vtt default>
</video>
</body>
205
Hopefully this helps the next person to stumble upon this SO question. I discovered that IE (10 and 11) does not support loading a cross-origin VTT file for a <track>, even if CORS is enabled. In order to add IE support for captions, I had to use a script like the one below.
This script downloads each VTT file via AJAX, creates a blob URL, and replaces each <track> src with its respective blob URL.
window.addEventListener("load", function() {
if (window.navigator.userAgent.indexOf("MSIE ") < 0 && window.navigator.userAgent.indexOf("Trident/") < 0) {
// Not IE, do nothing.
return;
}
var tracks = document.querySelectorAll("track")
for (var i = 0; i < tracks.length; i++) {
loadTrackWithAjax(tracks[i]);
}
});
function loadTrackWithAjax(track) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200 && this.responseText) {
// If VTT fetch succeeded, replace the src with a BLOB URL.
var blob = new Blob([this.responseText], { type: 'text/vtt' });
track.setAttribute("src", URL.createObjectURL(blob));
}
};
xhttp.open("GET", track.src, true);
xhttp.send();
}<video controls preload width="600" height="337.5" autoplay crossorigin="anonymous">
<source src="https://cdn.plyr.io/static/demo/View_From_A_Blue_Moon_Trailer-576p.mp4" type="video/mp4"></source>
<track kind="captions" label="English" srclang="en" src="https://cdn.plyr.io/static/demo/View_From_A_Blue_Moon_Trailer-HD.en.vtt" default>
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