You can use XML Field to embed YouTube videos.
Here's a short tutorial with the minimum steps required to make this work.
Configuration
- Enable the XML Field Extras module.
- Create a new XML field on your entity, calling it something like YouTube Snippet.
- Set the validation type to: YouTube Snippets
- Leave the schema blank and uncheck all of the schema setting options.
- Set up the default options as you desire.
Widget Type
- Enable the XML Field CodeMirror module, if desired.
- Set the widget type to CodeMirror XML.
Manage Display
- 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.