You can use XML Field to embed YouTube videos.

Here's a short tutorial with the minimum steps required to make this work.

Configuration

  1. Enable the XML Field Extras module.
  2. Create a new XML field on your entity, calling it something like YouTube Snippet.
  3. Set the validation type to: YouTube Snippets
  4. Leave the schema blank and uncheck all of the schema setting options.
  5. Set up the default options as you desire.

Widget Type

  1. Enable the XML Field CodeMirror module, if desired.
  2. Set the widget type to CodeMirror XML.

Manage Display

  1. Set the format to RAW XML.

This recipe insures that only YouTube snippets are pasted into the field and that code is rendered directly to the browser.