Persist caption settings

assets/js/player.js

@@ -5,6 +5,7 @@ var video_data = JSON.parse(document.getElementById('video_data').textContent);
 var options = {
     liveui: true,
     playbackRates: [0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0],
+    persistTextTrackSettings: true,
     controlBar: {
         children: [
             'playToggle',