Hi Phil,
Just saw your answers, and they grabbed my attention. My problem is similar to Craig's.
In our case, we have the video pages indexed, but not the videos itself. We added both page URL (<loc>) and video content location (video:content_loc) in the video sitemap.
Is there a chance of canibalization or prioritization, since only the content loc URL has been indexed by Google, instead the full page URL?
Note: we added the schema.org properties as well (Embed URL).
Thanks</video:content_loc></loc>