Merge pull request #573 from videojs/fix-ie11

Work around a bug with the buffered property in IE11 that prevented playback

@@ -305,6 +305,7 @@ const filterBufferedRanges = function(predicate) {
     let i;
     let ranges = [];
     let tech = this.tech_;
+
     // !!The order of the next two assignments is important!!
     // `currentTime` must be equal-to or greater-than the start of the
     // buffered range. Flash executes out-of-process so, every value can
@@ -317,6 +318,15 @@ const filterBufferedRanges = function(predicate) {
       time = tech.currentTime();
     }
 
+    // IE 11 has a bug where it will report a the video as fully buffered
+    // before any data has been loaded. This is a work around where we
+    // report a fully empty buffer until SourceBuffers have been created
+    // which is after a segment has been loaded and transmuxed.
+    if (!this.mediaSource ||
+        !this.mediaSource.mediaSource_.sourceBuffers.length) {
+      return videojs.createTimeRanges([]);
+    }
+
     if (buffered && buffered.length) {
       // Search for a range containing the play-head
       for (i = 0; i < buffered.length; i++) {

@@ -172,6 +172,11 @@ class MockMediaSource extends videojs.EventTarget {
     super();
     this.duration = NaN;
     this.seekable = videojs.createTimeRange();
+    this.mediaSource_ = {
+      // Mock a fake sourceBuffer array because of an IE11 work-around
+      // in `filterBufferedRanges`
+      sourceBuffers: ['fake']
+    };
   }
   addSeekableRange_(start, end) {
     this.seekable = videojs.createTimeRange(start, end);
@@ -747,6 +752,33 @@ QUnit.test('starts downloading a segment on loadedmetadata', function() {
                     'the first segment is requested');
 });
 
+QUnit.test('always returns an empty buffered region when there are no SourceBuffers', function() {
+  this.player.src({
+    src: 'manifest/media.m3u8',
+    type: 'application/vnd.apple.mpegurl'
+  });
+  this.player.tech_.buffered = function() {
+    return videojs.createTimeRanges([[0, 10]]);
+  };
+  openMediaSource(this.player, this.clock);
+
+  standardXHRResponse(this.requests[0]);
+  standardXHRResponse(this.requests[1]);
+  this.player.currentTime(3);
+  this.clock.tick(1);
+
+  QUnit.equal(this.player.tech_.hls.findBufferedRange_().end(0),
+              10,
+              'inside the first buffered region');
+
+  // Simulate the condition with no source buffers
+  this.player.hls.mediaSource.mediaSource_.sourceBuffers = [];
+
+  QUnit.equal(this.player.tech_.hls.findBufferedRange_().length,
+              0,
+              'empty TimeRanges returned');
+});
+
 QUnit.test('finds the correct buffered region based on currentTime', function() {
   this.player.src({
     src: 'manifest/media.m3u8',