Similar to a conventional website sitemap, a Video Sitemap usually contains a list of all videos on a website so Google can index, categorise and effectively display the video content of your website in its Search Engine Results Page (SERP).
In addition to containing links to the various locations of video within your website, a Video Sitemap also helps tell Google various other useful information about the video that you can add to the sitemap such as the running time, the category, title and description of the video.
Why submit a Video Sitemap
Submitting a Video Sitemap is important. In most cases, unless you have submitted one, Google may not display the video within your listing in its SERP even if the said page has a video (However, there still is a chance for the video to appear if you have embedded the video via a video sharing site such as YouTube). Having your listing supplemented with a video can significantly enhance the Click-through rates of your listing.
Another reason is to improve your website’s SEO. Websites which contain a video can have up to a 50 times greater chance of appearing within the first page of SERP. By submitting a Video Sitemap, you’ll be doing everything you can to make sure that Google is aware of the video content of your website (For more information on this top, check out Carrying out SEO for videos).
For help on creating a Video Sitemap, check out the official Google Webmasters help page