Matt Cutts, head of Google's WebSpam team and SEO mouthpiece for the company, is on record as saying the implementation of schema markup on a website isn't a direct ranking factor. However, in answer to a question about adding schema.org markup to videos even if they are on YouTube, he has just confirmed that Google highly recommends the use of rich snippets on a unique video landing page, even if the video itself is a YouTube embed. Cutts usually keeps things pretty close to his chest when it comes to giving out clues to what works and what doesn't in terms of search optimization, but in one of his most direct answers yet, he makes it clear that video markup is extremely important to Google for helping them understand the context of the page, and also the site itself.
Question: Rich snippets are automatically added to SERPS (Search Engine Results Pages) results from YouTube. Is it recommended to add schema video markup onsite in order to get your page with embedded video to rank in SERPS in addition to the YouTube results, or is this redundant?
To which Matt Cutts answered:
What Is Video Schema Markup?
In April 2012, we confirmed that Google were indexing site pages with embedded YouTube videos, which meant that your site could appear in the SERPS for that video, even if you didn't submit a video sitemap to Google Webmaster Tools. This was a pretty huge step forward, but just because Google can index your video landing page, it doesn't mean that it's going to return it for a user query every time. There are too many variables involved in our post-Hummingbird world for that ever to be guaranteed.
However, the use of rich snippets on a unique video landing page gives Google, and other search engines, much more information regarding that content and gives them more reason to return that page as a result to the user. On-page markup is an effective way of assisting search engines to understand the information contained on a web page and, armed with this extra data, they can provide more relevant search results. If you don't make your content as clear and as readable as possible and another site does, the chances are they are going to appear higher in the SERPS than you are because they have given Google a reason to consider them a more valid option.
If you are familiar with coding then adding microdata to your site should be straightforward. There are some excellent tutorials about, and of course, Google have provided information on the subject. If in doubt, you can ask your web developer or SEO agency to do the work for you. Be sure that every section of the markup is used, including the thumbnail, and use the Rich Snippet Testing Tool to validate each line of code.