diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index 3ac86a3e19..6fa978c099 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -1983,6 +1983,7 @@ function wp_get_mime_types() {
 	'rtx' => 'text/richtext',
 	'css' => 'text/css',
 	'htm|html' => 'text/html',
+	'vtt' => 'text/vtt',
 	// Audio formats
 	'mp3|m4a|m4b' => 'audio/mpeg',
 	'ra|ram' => 'audio/x-realaudio',
diff --git a/src/wp-includes/js/media-editor.js b/src/wp-includes/js/media-editor.js
index f065c0e8b0..bdb72abb32 100644
--- a/src/wp-includes/js/media-editor.js
+++ b/src/wp-includes/js/media-editor.js
@@ -609,26 +609,33 @@
 			poster : '',
 			loop : false,
 			autoplay : false,
-			preload : 'metadata'
+			preload : 'metadata',
+			content : ''
 		},
 
 		edit : function (data) {
-			var frame, shortcode = wp.shortcode.next( 'video', data ).shortcode;
+			var frame,
+				defaults = this.defaults,
+				shortcode = wp.shortcode.next( 'video', data ).shortcode,
+				attrs;
+
+			attrs = shortcode.attrs.named;
+			attrs.content = shortcode.content;
+
 			frame = wp.media({
 				frame: 'video',
 				state: 'video-details',
-				metadata: _.defaults(
-					shortcode.attrs.named,
-					wp.media.video.defaults
-				)
+				metadata: _.defaults( attrs, defaults )
 			});
 
 			return frame;
 		},
 
 		shortcode : function (shortcode) {
-			var self = this;
-			_.each( wp.media.video.defaults, function( value, key ) {
+			var self = this, content = shortcode.content;
+			delete shortcode.content;
+
+			_.each( this.defaults, function( value, key ) {
 				shortcode[ key ] = self.coerce( shortcode, key );
 
 				if ( value === shortcode[ key ] ) {
@@ -638,7 +645,8 @@
 
 			return wp.shortcode.string({
 				tag:     'video',
-				attrs:   shortcode
+				attrs:   shortcode,
+				content: content
 			});
 		}
 	}, wp.media.mixin);
diff --git a/src/wp-includes/js/media-views.js b/src/wp-includes/js/media-views.js
index 1bfe15a305..e0d181c472 100644
--- a/src/wp-includes/js/media-views.js
+++ b/src/wp-includes/js/media-views.js
@@ -1193,41 +1193,16 @@
 	media.controller.MediaLibrary = media.controller.Library.extend({
 		defaults: _.defaults({
 			filterable: 'uploaded',
-			multiple:   false,
 			priority:   80,
 			syncSelection: false,
-			displaySettings: true
+			displaySettings: false
 		}, media.controller.Library.prototype.defaults ),
 
 		initialize: function( options ) {
-			var library, comparator;
-
 			this.media = options.media;
 			this.set( 'library', media.query({ type: options.type }) );
 
 			media.controller.Library.prototype.initialize.apply( this, arguments );
-
-			library    = this.get('library');
-			comparator = library.comparator;
-
-			// Overload the library's comparator to push items that are not in
-			// the mirrored query to the front of the aggregate collection.
-			library.comparator = function( a, b ) {
-				var aInQuery = !! this.mirroring.get( a.cid ),
-					bInQuery = !! this.mirroring.get( b.cid );
-
-				if ( ! aInQuery && bInQuery ) {
-					return -1;
-				} else if ( aInQuery && ! bInQuery ) {
-					return 1;
-				} else {
-					return comparator.apply( this, arguments );
-				}
-			};
-
-			// Add all items in the selection to the library, so any featured
-			// images that are not initially loaded still appear.
-			library.observe( this.get('selection') );
 		}
 	});
 
@@ -2952,6 +2927,7 @@
 			this.on( 'toolbar:render:replace-video', this.renderReplaceToolbar, this );
 			this.on( 'toolbar:render:add-video-source', this.renderAddSourceToolbar, this );
 			this.on( 'toolbar:render:select-poster-image', this.renderSelectPosterImageToolbar, this );
+			this.on( 'toolbar:render:add-track', this.renderAddTrackToolbar, this );
 		},
 
 		createStates: function() {
@@ -2987,6 +2963,15 @@
 					toolbar: 'select-poster-image',
 					media: this.media,
 					menu: 'video-details'
+				} ),
+
+				new media.controller.MediaLibrary( {
+					type: 'text',
+					id: 'add-track',
+					title: l10n.videoAddTrackTitle,
+					toolbar: 'add-track',
+					media: this.media,
+					menu: 'video-details'
 				} )
 			]);
 		},
@@ -3010,6 +2995,43 @@
 
 							state.trigger( 'set-poster-image', controller.media.toJSON() );
 
+							// Restore and reset the default state.
+							controller.setState( controller.options.state );
+							controller.reset();
+						}
+					}
+				}
+			}) );
+		},
+
+		renderAddTrackToolbar: function() {
+			this.toolbar.set( new media.view.Toolbar({
+				controller: this,
+				items: {
+					replace: {
+						style:    'primary',
+						text:     l10n.videoAddTrackTitle,
+						priority: 80,
+
+						click: function() {
+							var controller = this.controller,
+								state = controller.state(),
+								selection = state.get( 'selection' ),
+								attachment = selection.single(),
+								content = controller.media.get( 'content' );
+
+							if ( -1 === content.indexOf( attachment.get( 'url' ) ) ) {
+								content += [
+									'<track srclang="en" label="English"kind="subtitles" src="',
+									attachment.get( 'url' ),
+									'" />'
+								].join('');
+
+								controller.media.set( 'content', content );
+							}
+
+							state.trigger( 'add-track', controller.media.toJSON() );
+
 							// Restore and reset the default state.
 							controller.setState( controller.options.state );
 							controller.reset();
@@ -6366,21 +6388,17 @@
 			this.on( 'media:setting:remove', this.render );
 			this.on( 'media:setting:remove', this.setPlayer );
 			this.events = _.extend( this.events, {
-				'click .remove-setting' : 'removeSetting'
+				'click .remove-setting' : 'removeSetting',
+				'change .content-track' : 'setTracks',
+				'click .remove-track' : 'setTracks'
 			} );
 
 			media.view.Settings.AttachmentDisplay.prototype.initialize.apply( this, arguments );
 		},
 
 		prepare: function() {
-			var attachment = false;
-
-			if ( this.model.attachment ) {
-				attachment = this.model.attachment.toJSON();
-			}
 			return _.defaults({
-				model: this.model.toJSON(),
-				attachment: attachment
+				model: this.model.toJSON()
 			}, this.options );
 		},
 
@@ -6404,12 +6422,26 @@
 		},
 
 		removeSetting : function (e) {
-			var setting = $( e.currentTarget ).parent();
+			var wrap = $( e.currentTarget ).parent(), setting;
 
-			this.model.unset( setting.find( 'input' ).data( 'setting' ) );
+			setting = wrap.find( 'input' ).data( 'setting' );
 
-			setting.remove();
+			if ( setting ) {
+				this.model.unset( setting );
+				this.trigger( 'media:setting:remove', this );
+			}
 
+			wrap.remove();
+		},
+
+		setTracks : function () {
+			var tracks = '';
+
+			_.each( this.$('.content-track'), function (track) {
+				tracks += $( track ).val();
+			} );
+
+			this.model.set( 'content', tracks );
 			this.trigger( 'media:setting:remove', this );
 		},
 
diff --git a/src/wp-includes/js/mediaelement/wp-mediaelement.css b/src/wp-includes/js/mediaelement/wp-mediaelement.css
index 6e3bb4b3b2..cf498e959d 100644
--- a/src/wp-includes/js/mediaelement/wp-mediaelement.css
+++ b/src/wp-includes/js/mediaelement/wp-mediaelement.css
@@ -19,6 +19,11 @@
 	max-width: 400px;
 }
 
+.media-embed-details .embed-media-settings .setting span {
+	max-width: 400px;
+	width: auto;
+}
+
 .media-embed-details .embed-media-settings {
 	padding-top: 0;
 }
@@ -28,8 +33,11 @@
 	max-width: 600px;
 }
 
+.media-embed-details .setting p,
 .media-embed-details .setting a {
 	color: #a00;
+	font-size: 10px;
+	text-transform: uppercase;
 }
 
 .media-embed-details .setting a:hover {
diff --git a/src/wp-includes/js/tinymce/plugins/wpgallery/plugin.js b/src/wp-includes/js/tinymce/plugins/wpgallery/plugin.js
index 018d91eb21..d33dbca088 100644
--- a/src/wp-includes/js/tinymce/plugins/wpgallery/plugin.js
+++ b/src/wp-includes/js/tinymce/plugins/wpgallery/plugin.js
@@ -97,11 +97,14 @@ tinymce.PluginManager.add('wpgallery', function( editor ) {
 			frame.on( 'close', function () {
 				frame.detach();
 			} );
-			frame.state( 'video-details' ).on( 'update replace add-source select-poster-image', function ( selection ) {
-				var shortcode = wp.media.video.shortcode( selection );
-				editor.dom.setAttrib( node, 'data-wp-media', window.encodeURIComponent( shortcode ) );
-				frame.detach();
-			} );
+			frame.state( 'video-details' ).on(
+				'update replace add-source select-poster-image add-track',
+				function ( selection ) {
+					var shortcode = wp.media.video.shortcode( selection );
+					editor.dom.setAttrib( node, 'data-wp-media', window.encodeURIComponent( shortcode ) );
+					frame.detach();
+				}
+			);
 			frame.open();
 		} else if ( editor.dom.hasClass( node, 'wp-audio' ) ) {
 			frame = wp.media.audio.edit( data );
diff --git a/src/wp-includes/media-template.php b/src/wp-includes/media-template.php
index 641be2f679..31d650a759 100644
--- a/src/wp-includes/media-template.php
+++ b/src/wp-includes/media-template.php
@@ -690,7 +690,7 @@ function wp_print_media_templates() {
 				<label class="setting">
 					<span>SRC</span>
 					<input type="text" disabled="disabled" data-setting="src" value="{{ data.model.src }}" />
-					<a class="remove-setting">{{{ wp.media.view.l10n.audioRemoveSource }}}</a>
+					<a class="remove-setting">{{{ wp.media.view.l10n.remove }}}</a>
 				</label>
 				<# } #>
 				<?php
@@ -700,7 +700,7 @@ function wp_print_media_templates() {
 				<label class="setting">
 					<span><?php echo strtoupper( $type ) ?></span>
 					<input type="text" disabled="disabled" data-setting="<?php echo $type ?>" value="{{ data.model.<?php echo $type ?> }}" />
-					<a class="remove-setting">{{{ wp.media.view.l10n.audioRemoveSource }}}</a>
+					<a class="remove-setting">{{{ wp.media.view.l10n.remove }}}</a>
 				</label>
 				<# } #>
 				<?php endforeach ?>
@@ -779,13 +779,14 @@ function wp_print_media_templates() {
 					?><# if ( data.model.<?php echo $type ?> ) { #>
 					<source src="{{ data.model.<?php echo $type ?> }}" type="{{ wp.media.view.settings.embedMimes[ '<?php echo $type ?>' ] }}" />
 					<# } #>
-					<?php endforeach;
-				?></video>
+					<?php endforeach; ?>
+					{{{ data.model.content }}}
+				</video>
 				<# if ( ! _.isEmpty( data.model.src ) ) { #>
 				<label class="setting">
 					<span>SRC</span>
 					<input type="text" disabled="disabled" data-setting="src" value="{{ data.model.src }}" />
-					<a class="remove-setting">{{{ wp.media.view.l10n.videoRemoveSource }}}</a>
+					<a class="remove-setting">{{{ wp.media.view.l10n.remove }}}</a>
 				</label>
 				<# } #>
 				<?php foreach ( $video_types as $type ):
@@ -793,7 +794,7 @@ function wp_print_media_templates() {
 				<label class="setting">
 					<span><?php echo strtoupper( $type ) ?></span>
 					<input type="text" disabled="disabled" data-setting="<?php echo $type ?>" value="{{ data.model.<?php echo $type ?> }}" />
-					<a class="remove-setting">{{{ wp.media.view.l10n.videoRemoveSource }}}</a>
+					<a class="remove-setting">{{{ wp.media.view.l10n.remove }}}</a>
 				</label>
 				<# } #>
 				<?php endforeach ?>
@@ -802,7 +803,7 @@ function wp_print_media_templates() {
 				<label class="setting">
 					<span><?php _e( 'Poster Image' ); ?></span>
 					<input type="text" disabled="disabled" data-setting="poster" value="{{ data.model.poster }}" />
-					<a class="remove-setting">{{{ wp.media.view.l10n.videoRemovePoster }}}</a>
+					<a class="remove-setting">{{{ wp.media.view.l10n.remove }}}</a>
 				</label>
 				<# } #>
 				<div class="setting preload">
@@ -824,6 +825,25 @@ function wp_print_media_templates() {
 					<input type="checkbox" data-setting="loop" />
 				</label>
 				<div class="clear"></div>
+
+				<label class="setting" data-setting="content">
+					<span><?php _e( 'Tracks (subtitles, captions, descriptions, chapters or metadata)' ); ?></span>
+					<#
+					var content = '';
+					if ( ! _.isEmpty( data.model.content ) ) {
+						var tracks = jQuery( data.model.content ).filter( 'track' );
+						_.each( tracks.toArray(), function (track) {
+							content += track.outerHTML; #>
+						<p>
+							<input class="content-track" type="text" value="{{ track.outerHTML }}" />
+							<a class="remove-setting remove-track">{{{ wp.media.view.l10n.remove }}}</a>
+						</p>
+						<# } ); #>
+					<# } else { #>
+					<em>There are no associated subtitles.</em>
+					<# } #>
+					<textarea class="hidden content-setting">{{ content }}</textarea>
+				</label>
 			</div>
 		</div>
 	</script>
diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index ce0338b037..0aadf8a995 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -2395,7 +2395,8 @@ function wp_enqueue_media( $args = array() ) {
 		'cancel'      => __( 'Cancel' ),
 		'update'      => __( 'Update' ),
 		'replace'     => __( 'Replace' ),
-		'back'     => __( 'Back' ),
+		'remove'      => __( 'Remove' ),
+		'back'        => __( 'Back' ),
 		/* translators: This is a would-be plural string used in the media manager.
 		   If there is not a word you can use in your language to avoid issues with the
 		   lack of plural support here, turn it into "selected: %d" then translate it.
@@ -2450,7 +2451,6 @@ function wp_enqueue_media( $args = array() ) {
 		'audioDetailsCancel'    => __( 'Cancel Edit' ),
 		'audioDetailsText'      => __( '"Replace Audio" will remove all associated source files when you update. ' .
 			'"Add Audio Source" allows you to specify alternate sources for maximum native HTML5 audio playback.' ),
-		'audioRemoveSource'     => __( 'Remove Audio Source' ),
 
 		// Edit Video
 		'videoDetailsTitle'     => __( 'Video Details' ),
@@ -2459,9 +2459,8 @@ function wp_enqueue_media( $args = array() ) {
 		'videoDetailsCancel'    => __( 'Cancel Edit' ),
 		'videoDetailsText'      => __( '"Replace Video" will remove all associated source files when you update. ' .
 			'"Add Video Source" allows you to specify alternate sources for maximum native HTML5 video playback.' ),
-		'videoRemoveSource'     => __( 'Remove Video Source' ),
 		'videoSelectPosterImageTitle' => _( 'Select Poster Image' ),
-		'videoRemovePoster'     => __( 'Remove Poster Image' ),
+		'videoAddTrackTitle'	=> __( 'Add Subtitles' ),
 
  		// Playlist
  		'playlistDragInfo'    => __( 'Drag and drop to reorder tracks.' ),