Safari ignore window.matchMedia

The issue is in the formatting, oddly enough the other browsers fix the behavior even though it is malformed. It's missing an additional closing ")" parenthesis after the 1025px. Try:

if ( window.matchMedia('(min-width:1025px)').matches) {
   console.log('match');

   document.addEventListener("DOMContentLoaded", function() { initialiseMediaPlayer(); }, false);

   function initialiseMediaPlayer() {

      (stuff here...)

   }

}

For anyone else who may come across similar issues, I found that in safari you need to include 'screen and' as well as the width setting. Other browsers seem to assume that you are talking about the screen width but safari needs it specified, at least in my case. so would be something like:

if ( window.matchMedia('screen and (min-width:1025px)').matches) {}

in this case

In my case, it was that Safari uses .addListener() instead of addEventListener() on the mediaQueryList.