diff --git a/src/wp-admin/includes/ajax-actions.php b/src/wp-admin/includes/ajax-actions.php
index 025c24e5ec..478dcb004f 100644
--- a/src/wp-admin/includes/ajax-actions.php
+++ b/src/wp-admin/includes/ajax-actions.php
@@ -2652,8 +2652,26 @@ function wp_ajax_parse_embed() {
 		) );
 	}
 
-	// TODO: needed?
-	$parsed = do_shortcode( $parsed );
+	if ( has_shortcode( $parsed, 'audio' ) || has_shortcode( $parsed, 'video' ) ) {
+		$styles = '';
+		$mce_styles = wp_media_mce_styles();
+		foreach ( $mce_styles as $style ) {
+			$styles .= sprintf( '<link rel="stylesheet" href="%s"/>', $style );
+		}
+
+		$html = do_shortcode( $parsed );
+
+		global $wp_scripts;
+		if ( ! empty( $wp_scripts ) ) {
+			$wp_scripts->done = array();
+		}
+		ob_start();
+		wp_print_scripts( 'wp-mediaelement' );
+		$scripts = ob_get_clean();
+
+		$parsed = $styles . $html . $scripts;
+	}
+
 
 	if ( ! empty( $no_ssl_support ) || ( is_ssl() && ( preg_match( '%<(iframe|script|embed) [^>]*src="http://%', $parsed ) ||
 		preg_match( '%<link [^>]*href="http://%', $parsed ) ) ) ) {
diff --git a/src/wp-includes/js/tinymce/skins/wordpress/wp-content.css b/src/wp-includes/js/tinymce/skins/wordpress/wp-content.css
index 5ac753f93c..2b5763a819 100644
--- a/src/wp-includes/js/tinymce/skins/wordpress/wp-content.css
+++ b/src/wp-includes/js/tinymce/skins/wordpress/wp-content.css
@@ -193,7 +193,6 @@ video,
 embed {
 	display: -moz-inline-stack;
 	display: inline-block;
-	max-width: 100%;
 }
 
 audio {
diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index c327008410..a7000b8726 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -3256,3 +3256,29 @@ function attachment_url_to_postid( $url ) {
 		return (int) $post_id;
 	}
 }
+
+/**
+ * Return the URls for CSS files used in an <iframe>-sandbox'd TinyMCE media view
+ *
+ * @since 4.0.0
+ *
+ * @global $wp_version
+ * @return array The relevant CSS file URLs.
+ */
+function wp_media_mce_styles() {
+ 	$version = 'ver=' . $GLOBALS['wp_version'];
+ 	$tinymce = includes_url( "js/tinymce/skins/lightgray/content.min.css?$version" );
+	$dashicons = includes_url( "css/dashicons.css?$version" );
+ 	$skin = includes_url( "js/tinymce/skins/wordpress/wp-content.css?$version" );
+ 	$mediaelement = includes_url( "js/mediaelement/mediaelementplayer.min.css?$version" );
+ 	$wpmediaelement = includes_url( "js/mediaelement/wp-mediaelement.css?$version" );
+
+ 	$mce_styles = array( $tinymce, $dashicons, $skin, $mediaelement, $wpmediaelement );
+ 	$editor_styles = get_editor_stylesheets();
+	if ( ! empty( $editor_styles ) ) {
+		foreach ( $editor_styles as $style ) {
+			$mce_styles[] = $style;
+		}
+	}
+	return $mce_styles;
+}
\ No newline at end of file
diff --git a/src/wp-includes/theme.php b/src/wp-includes/theme.php
index 912a49c0b6..f21075a116 100644
--- a/src/wp-includes/theme.php
+++ b/src/wp-includes/theme.php
@@ -1394,6 +1394,54 @@ function remove_editor_styles() {
 	return true;
 }
 
+/**
+ * Retrieve any registered editor stylesheets
+ *
+ * @since 4.0.0
+ *
+ * @global $editor_styles Registered editor stylesheets
+ *
+ * @return array If registered, a list of editor stylesheet URLs.
+ */
+function get_editor_stylesheets() {
+	$stylesheets = array();
+	// load editor_style.css if the current theme supports it
+	if ( ! empty( $GLOBALS['editor_styles'] ) && is_array( $GLOBALS['editor_styles'] ) ) {
+		$editor_styles = $GLOBALS['editor_styles'];
+
+		$editor_styles = array_unique( array_filter( $editor_styles ) );
+		$style_uri = get_stylesheet_directory_uri();
+		$style_dir = get_stylesheet_directory();
+
+		// Support externally referenced styles (like, say, fonts).
+		foreach ( $editor_styles as $key => $file ) {
+			if ( preg_match( '~^(https?:)?//~', $file ) ) {
+				$stylesheets[] = esc_url_raw( $file );
+				unset( $editor_styles[ $key ] );
+			}
+		}
+
+		// Look in a parent theme first, that way child theme CSS overrides.
+		if ( is_child_theme() ) {
+			$template_uri = get_template_directory_uri();
+			$template_dir = get_template_directory();
+
+			foreach ( $editor_styles as $key => $file ) {
+				if ( $file && file_exists( "$template_dir/$file" ) ) {
+					$stylesheets[] = "$template_uri/$file";
+				}
+			}
+		}
+
+		foreach ( $editor_styles as $file ) {
+			if ( $file && file_exists( "$style_dir/$file" ) ) {
+				$stylesheets[] = "$style_uri/$file";
+			}
+		}
+	}
+	return $stylesheets;
+}
+
 /**
  * Allows a theme to register its support of a certain feature
  *