Index: src/wp-includes/class-wp-embed.php
===================================================================
--- src/wp-includes/class-wp-embed.php	(revision 27063)
+++ src/wp-includes/class-wp-embed.php	(working copy)
@@ -289,7 +289,7 @@
 	 * @return string Potentially modified $content.
 	 */
 	function autoembed( $content ) {
-		return preg_replace_callback( '|^\s*(https?://[^\s"]+)\s*$|im', array( $this, 'autoembed_callback' ), $content );
+        return preg_replace_callback( '|(?<!")(https?://[^\s"\[<]+)|im', array( $this, 'autoembed_callback' ), $content );
 	}
 
 	/**