Merge pull request #6510 from smarnach/safari-video-speed

Work around a Youtube API bug that causes Safari to ignore the stored speed

common/lib/xmodule/xmodule/js/src/video/03_video_player.js

@@ -86,7 +86,7 @@ function (HTML5Video, Resizer) {
     //     via the 'state' object. Much easier to work this way - you don't
     //     have to do repeated jQuery element selects.
     function _initialize(state) {
-        var youTubeId, player;
+        var youTubeId, player, userAgent;
 
         // The function is called just once to apply pre-defined configurations
         // by student before video starts playing. Waits until the video's
@@ -96,6 +96,16 @@ function (HTML5Video, Resizer) {
             $(window).on('unload', state.saveState);
 
             if (!state.isFlashMode() && state.speed != '1.0') {
+
+                // Work around a bug in the Youtube API that causes videos to
+                // play at normal speed rather than at the configured speed in
+                // Safari.  Setting the playback rate to 1.0 *after* playing
+                // started and then to the actual value tricks the player into
+                // picking up the speed setting.
+                if (state.browserIsSafari && state.isYoutubeType()) {
+                    state.videoPlayer.setPlaybackRate(1.0, false);
+                }
+
                 state.videoPlayer.setPlaybackRate(state.speed, true);
             }
         });
@@ -125,19 +135,13 @@ function (HTML5Video, Resizer) {
             state.videoPlayer.playerVars.html5 = 1;
         }
 
-        // There is a bug which prevents YouTube API to correctly set the speed
-        // to 1.0 from another speed in Firefox when in HTML5 mode. There is a
-        // fix which basically reloads the video at speed 1.0 when this change
-        // is requested (instead of simply requesting a speed change to 1.0).
-        // This has to be done only when the video is being watched in Firefox.
-        // We need to figure out what browser is currently executing this code.
-        //
-        // TODO: Check the status of
-        // http://code.google.com/p/gdata-issues/issues/detail?id=4654
-        // When the YouTube team fixes the API bug, we can remove this
-        // temporary bug fix.
-        state.browserIsFirefox = navigator.userAgent
-            .toLowerCase().indexOf('firefox') > -1;
+        // Detect the current browser for several browser-specific work-arounds.
+        userAgent = navigator.userAgent.toLowerCase();
+        state.browserIsFirefox = userAgent.indexOf('firefox') > -1;
+        state.browserIsChrome = userAgent.indexOf('chrome') > -1;
+        // Chrome includes both "Chrome" and "Safari" in the user agent.
+        state.browserIsSafari = (userAgent.indexOf('safari') > -1 &&
+                                 !state.browserIsChrome);
 
         if (state.videoType === 'html5') {
             state.videoPlayer.player = new HTML5Video.Player(state.el, {
@@ -356,6 +360,18 @@ function (HTML5Video, Resizer) {
             time = this.videoPlayer.currentTime,
             methodName, youtubeId;
 
+        // There is a bug which prevents YouTube API to correctly set the speed
+        // to 1.0 from another speed in Firefox when in HTML5 mode. There is a
+        // fix which basically reloads the video at speed 1.0 when this change
+        // is requested (instead of simply requesting a speed change to 1.0).
+        // This has to be done only when the video is being watched in Firefox.
+        // We need to figure out what browser is currently executing this code.
+        //
+        // TODO: Check the status of
+        // http://code.google.com/p/gdata-issues/issues/detail?id=4654
+        // When the YouTube team fixes the API bug, we can remove this
+        // temporary bug fix.
+
         // If useCueVideoById is true it will reload video again.
         // Used useCueVideoById to fix the issue video not playing if we change
         // the speed before playing the video.