Are there any embedded video/media field modules which integrate with Rules? I'm trying to set up some Rules conditions which deal with whether or not a user has added a YouTube URL into a media field for a node. The idea is to use a Media type module to embed the YouTube video into the forum post. But I want a specific Rule to fire if the user saves their forum post without adding a YouTube video URL to that custom field.

However, I can't seem to find a module like Media or Video Embed Field, or Embedded Media field which expose that field entity to Rules.
You could use a hook_form_alter() to check if a youtube video has been added. Then run rules_invoke_event() to trigger the rule.

Btw, I personally like the Video Embed Field module.