Find youtube Link in PHP string and Convert it into embed code?

A quick function for generating Embed url link of any of the FB/vimeo/youtube videos.

public function generateVideoEmbedUrl($url){
    //This is a general function for generating an embed link of an FB/Vimeo/Youtube Video.
    $finalUrl = '';
    if(strpos($url, 'facebook.com/') !== false) {
        //it is FB video
        $finalUrl.='https://www.facebook.com/plugins/video.php?href='.rawurlencode($url).'&show_text=1&width=200';
    }else if(strpos($url, 'vimeo.com/') !== false) {
        //it is Vimeo video
        $videoId = explode("vimeo.com/",$url)[1];
        if(strpos($videoId, '&') !== false){
            $videoId = explode("&",$videoId)[0];
        }
        $finalUrl.='https://player.vimeo.com/video/'.$videoId;
    }else if(strpos($url, 'youtube.com/') !== false) {
        //it is Youtube video
        $videoId = explode("v=",$url)[1];
        if(strpos($videoId, '&') !== false){
            $videoId = explode("&",$videoId)[0];
        }
        $finalUrl.='https://www.youtube.com/embed/'.$videoId;
    }else if(strpos($url, 'youtu.be/') !== false){
        //it is Youtube video
        $videoId = explode("youtu.be/",$url)[1];
        if(strpos($videoId, '&') !== false){
            $videoId = explode("&",$videoId)[0];
        }
        $finalUrl.='https://www.youtube.com/embed/'.$videoId;
    }else{
        //Enter valid video URL
    }
    return $finalUrl;
}

There are two types of youtube link for one video:

Example:

$link1 = 'https://www.youtube.com/watch?v=NVcpJZJ60Ao';
$link2 = 'https://www.youtu.be/NVcpJZJ60Ao';

This function handles both:

function getYoutubeEmbedUrl($url)
{
     $shortUrlRegex = '/youtu.be\/([a-zA-Z0-9_-]+)\??/i';
     $longUrlRegex = '/youtube.com\/((?:embed)|(?:watch))((?:\?v\=)|(?:\/))([a-zA-Z0-9_-]+)/i';

    if (preg_match($longUrlRegex, $url, $matches)) {
        $youtube_id = $matches[count($matches) - 1];
    }

    if (preg_match($shortUrlRegex, $url, $matches)) {
        $youtube_id = $matches[count($matches) - 1];
    }
    return 'https://www.youtube.com/embed/' . $youtube_id ;
}

The output of $link1 or $link2 would be the same :

 $output1 = getYoutubeEmbedUrl($link1);
 $output2 = getYoutubeEmbedUrl($link2);
 // output for both:  https://www.youtube.com/embed/NVcpJZJ60Ao

Now you can use the output in iframe!

Try this:

preg_replace("/\s*[a-zA-Z\/\/:\.]*youtube.com\/watch\?v=([a-zA-Z0-9\-_]+)([a-zA-Z0-9\/\*\-\_\?\&\;\%\=\.]*)/i","<iframe width=\"420\" height=\"315\" src=\"//www.youtube.com/embed/$1\" frameborder=\"0\" allowfullscreen></iframe>",$post_details['description']);

A little enhancement of Joran's solution to handle also youtube short URL format:

function convertYoutube($string) {
    return preg_replace(
        "/\s*[a-zA-Z\/\/:\.]*youtu(be.com\/watch\?v=|.be\/)([a-zA-Z0-9\-_]+)([a-zA-Z0-9\/\*\-\_\?\&\;\%\=\.]*)/i",
        "<iframe src=\"//www.youtube.com/embed/$2\" allowfullscreen></iframe>",
        $string
    );
}

You can test this function online here