How to add og:video tag at my site?
new version of XML Sitemap module helped me.


  The XML sitemap module creates a sitemap that conforms to the
  sitemaps.org specification. This helps search engines to more
  intelligently crawl a website and keep their results up to date. The
  sitemap created by the module can be automatically submitted to Ask,
  Google, Bing (formerly Windows Live Search), and Yahoo! search
  engines. The module also comes with several submodules that can add
  sitemap links for content, menu items, taxonomy terms, and user
  profiles.