Scrape iframe嵌入代码

I have a simple php scrape that I have managed to set up that grabs the title and image off a page

$post=$_POST['post'];

$html = file_get_html($post);
$title = $html->find('h2', 1);
$imageurl = $html->find('img', 1); 

echo $title->plaintext."<br>
";
echo $imageurl->src;

But Im also trying to grab the video embed code, that uses an iframe like this

 <input type="text" name="media_embed_code" id="mediaEmbedCodeInput" size="110" onclick="this.focus();this.select();" value="&lt;iframe src=&quot;http://drunksportsfans.com/embedframe/537&quot; frameborder=0 width=510 height=400 scrolling=no&gt;&lt;/iframe&gt;">

I just need the value part, but its clearly more complicated than the title and image

This is simple enough:

$value_of_input = $html->find('input[name=media_embed_code]', 0)->value;