Autoplay YouTube in Custom Fields

I am tryign to make youtube autoplay in custom fields.

function youtubes($content)
{
$content = str_replace("SRC","src",$content);
$content = str_replace("'",'"',$content);
preg_match('/src="([^"]+)"/', $content, $matches);
 if ( isset($matches[1]) )
     {
$cnt = $matches[1];
    return '<div id="youtubes"><iframe width="560" height="315" src="'.$cnt.'?autoplay=1" frameborder="0" allowfullscreen></iframe></div>';
}
}

add_filter('the_content','youtubes');

This is filter for content in post body, how to make same for custom fields?