How to rewrite video urls from /feed that have autoplay enabled

I ran into an interesting Issue today working on a Wall Feed Plugin. A majority of videos posted to the feed via youtube have autoplay enabled.

"source": "http://www.youtube.com/v/IXTS79iDTNA?version=3&autohide=1&autoplay=1",

I am trying to rewrite that url before embeding using php. How would you do this?

So far i have tried using strtr(); with array, seems though if there are alot of videos in the feed, things seem to slow down alot.

    /* $fvalue[source] is the video url in graph api */ 
    if($fvalue[source]){
            $reWrite = array("autoplay=1" => "autoplay=0");
        $getEmbed = $fvalue[source];
        $strAuto = strtr($getEmbed, $reWrite);
        echo '<object><embed src="'.$strAuto.'"></embed></object>';
    }

It is slow because of the strstr. Roughly speaking, str_replace is 30-50 times faster.

//This code should be at least 30 times faster.
if($fvalue[source]){
    $strAuto = str_replace("autoplay=1", "autoplay=0", $fvalue[source]);
    echo '<object><embed src="'.$strAuto.'"></embed></object>';
}