Merge pull request #180 from videojs/dont-downshift

Don't downshift in smart shifting.

@@ -109,7 +109,7 @@ videojs.Hls.prototype.handleSourceOpen = function() {
   this.playlists = new videojs.Hls.PlaylistLoader(this.src_, settings.withCredentials);
 
   this.playlists.on('loadedmetadata', videojs.bind(this, function() {
-    var selectedPlaylist, loaderHandler, newBitrate, segmentDuration,
+    var selectedPlaylist, loaderHandler, oldBitrate, newBitrate, segmentDuration,
         segmentDlTime, setupEvents, threshold;
 
     setupEvents = function() {
@@ -127,8 +127,10 @@ videojs.Hls.prototype.handleSourceOpen = function() {
     oldMediaPlaylist = this.playlists.media();
     this.bandwidth = this.playlists.bandwidth;
     selectedPlaylist = this.selectPlaylist();
+    oldBitrate = oldMediaPlaylist.attributes &&
+                 oldMediaPlaylist.attributes.BANDWIDTH || 0;
     newBitrate = selectedPlaylist.attributes &&
-                 selectedPlaylist.attributes.BANDWIDTH;
+                 selectedPlaylist.attributes.BANDWIDTH || 0;
     segmentDuration = oldMediaPlaylist.segments &&
                       oldMediaPlaylist.segments[this.mediaIndex].duration ||
                       oldMediaPlaylist.targetDuration;
@@ -143,7 +145,7 @@ videojs.Hls.prototype.handleSourceOpen = function() {
     // request which is a somewhat small file.
     threshold = 10;
 
-    if (segmentDlTime <= threshold) {
+    if (newBitrate > oldBitrate && segmentDlTime <= threshold) {
       this.playlists.media(selectedPlaylist);
       loaderHandler = videojs.bind(this, function() {
         setupEvents.call(this);

@@ -368,7 +368,7 @@ test('downloads media playlists after loading the master', function() {
               'first segment requested');
 });
 
-test('downloads a second media playlist before playback, if bandwidth is high', function() {
+test('upshift if initial bandwidth is high', function() {
   player.src({
     src: 'manifest/master.m3u8',
     type: 'application/vnd.apple.mpegurl'
@@ -378,11 +378,12 @@ test('downloads a second media playlist before playback, if bandwidth is high',
   standardXHRResponse(requests[0]);
 
   player.hls.playlists.setBandwidth = function() {
-    player.hls.playlists.bandwidth = 100000;
+    player.hls.playlists.bandwidth = 1000000000;
   };
 
   standardXHRResponse(requests[1]);
   standardXHRResponse(requests[2]);
+
   standardXHRResponse(requests[3]);
 
   strictEqual(requests[0].url, 'manifest/master.m3u8', 'master playlist requested');
@@ -394,12 +395,41 @@ test('downloads a second media playlist before playback, if bandwidth is high',
   strictEqual(requests[2].url,
               window.location.origin +
               window.location.pathname.split('/').slice(0, -1).join('/') +
-              '/manifest/media1.m3u8',
+              '/manifest/media3.m3u8',
               'media playlist requested');
   strictEqual(requests[3].url,
               window.location.origin +
               window.location.pathname.split('/').slice(0, -1).join('/') +
-              '/manifest/media1-00001.ts',
+              '/manifest/media3-00001.ts',
+              'first segment requested');
+});
+
+test('dont downshift if bandwidth is low', function() {
+  player.src({
+    src: 'manifest/master.m3u8',
+    type: 'application/vnd.apple.mpegurl'
+  });
+  openMediaSource(player);
+
+  standardXHRResponse(requests[0]);
+
+  player.hls.playlists.setBandwidth = function() {
+    player.hls.playlists.bandwidth = 100;
+  };
+
+  standardXHRResponse(requests[1]);
+  standardXHRResponse(requests[2]);
+
+  strictEqual(requests[0].url, 'manifest/master.m3u8', 'master playlist requested');
+  strictEqual(requests[1].url,
+              window.location.origin +
+              window.location.pathname.split('/').slice(0, -1).join('/') +
+              '/manifest/media.m3u8',
+              'media playlist requested');
+  strictEqual(requests[2].url,
+              window.location.origin +
+              window.location.pathname.split('/').slice(0, -1).join('/') +
+              '/manifest/media-00001.ts',
               'first segment requested');
 });