Embed YouTube & Vimeo Videos After you've copied the iFrame embed code for the YouTube or Vimeo video, follow these directions to edit the code to embed the video directly your Sitecore page. In ...

So the short version is you can’t. In particular if a page is embedded within an iframe, within a bigger other page, then it's possible that we will index that embedding page as well.

Furthermore, portals can also overwrite the main URL address bar, meaning they are useful as a navigation system, and more than embedding content --the most common way in which iframes are used today.