Preg_match文本php不起作用

Hello I would like to use preg_match I have it, why don't work?

$source = "<span class=\"middle\">".
    "<span class=\"play\"></span>". 
    "<img width=\"114\" src=\"http://i.ytimg.com/vi/PnmEKNi1DtY/default.jpg\" alt=\"\"></span> 1";


preg_match("'<span class=\"middle\"><span class=\"play\"></span> <img width=\"114\" src=\"http://i.ytimg.com/vi/(.*?)/default.jpg\" alt=\"\"></span> 1'si", $source, $match);

  foreach($match[1] as $val)
    {
        echo $val."<br>";


    }

Outputs:

Warning: Invalid argument supplied for foreach()

Because $match[0] is a scalar, not an array. You'd use:

foreach($match as $val)