use moodle url for path to mod oc player

filter.php

@@ -47,7 +47,7 @@ class filter_opencast extends moodle_text_filter
      * @throws dml_exception
      */
     public function filter($text, array $options = array()) {
-        global $PAGE;
+        global $CFG, $PAGE;
         $i = 0;
 
         if (stripos($text, '</video>') === false) {
@@ -122,6 +122,7 @@ class filter_opencast extends moodle_text_filter
                             $mustachedata->data = json_encode($data);
                             $mustachedata->width = $width;
                             $mustachedata->height = $height;
+                            $mustachedata->modplayerpath = (new moodle_url('/mod/opencast/player.html'))->out();
 
                             if (count($data['streams']) === 1) {
                                 $sources = $data['streams'][0]['sources'];

templates/player.mustache

@@ -27,6 +27,7 @@
       "height": "250",
       "playerid": "ocplayer_0",
       "configurl": "/filter/opencast/config.json",
+      "modplayerpath": "/mod/opencast/player.html",
       "data": "{"metadata":{"title": "Test video", "etc": "..."}"
   }
 }}
@@ -37,7 +38,7 @@
 {{^resolution}}
 <div class="filter-opencast player-wrapper">
 {{/resolution}}
-    <iframe src="/mod/opencast/player.html" class="filter-player-iframe" id="{{playerid}}" allowfullscreen></iframe>
+    <iframe src="{{modplayerpath}}" class="filter-player-iframe" id="{{playerid}}" allowfullscreen></iframe>
 </div>
 
 <script>