Index: src/wp-includes/class-oembed.php
===================================================================
--- src/wp-includes/class-oembed.php	(revision 32900)
+++ src/wp-includes/class-oembed.php	(working copy)
@@ -34,10 +34,10 @@
 	 */
 	public function __construct() {
 		$providers = array(
-			'#http://(www\.)?youtube\.com/watch.*#i'              => array( 'http://www.youtube.com/oembed',                      true  ),
-			'#https://(www\.)?youtube\.com/watch.*#i'             => array( 'http://www.youtube.com/oembed?scheme=https',         true  ),
-			'#http://(www\.)?youtube\.com/playlist.*#i'           => array( 'http://www.youtube.com/oembed',                      true  ),
-			'#https://(www\.)?youtube\.com/playlist.*#i'          => array( 'http://www.youtube.com/oembed?scheme=https',         true  ),
+			'#http://((m|www)\.)?youtube\.com/watch.*#i'          => array( 'http://www.youtube.com/oembed',                      true  ),
+			'#https://((m|www)\.)?youtube\.com/watch.*#i'         => array( 'http://www.youtube.com/oembed?scheme=https',         true  ),
+			'#http://((m|www)\.)?youtube\.com/playlist.*#i'       => array( 'http://www.youtube.com/oembed',                      true  ),
+			'#https://((m|www)\.)?youtube\.com/playlist.*#i'      => array( 'http://www.youtube.com/oembed?scheme=https',         true  ),
 			'#http://youtu\.be/.*#i'                              => array( 'http://www.youtube.com/oembed',                      true  ),
 			'#https://youtu\.be/.*#i'                             => array( 'http://www.youtube.com/oembed?scheme=https',         true  ),
 			'http://blip.tv/*'                                    => array( 'http://blip.tv/oembed/',                             false ),