Often a website which hosts videos will have a common top-level page that groups conceptually related videos together. Such a page may be of interest to a user searching on that subject. Sites with many videos about a single subject can group these videos together on a top-level page, often known as a gallery. This can make it easier for users to find exactly what they're looking for. In this case, you can use a Sitemap to tell Google the URL of the gallery page on which each video appears.
You can specify the URL of the gallery level page using the optional tag <video:gallery_loc> on a per-video basis. Note that only one gallery_loc is allowed per video.
For more information on Google Videos, including Sitemap specifications, please visit our Help Center. To post questions and search for answers, check out our Help Forum.
Posted by Nelson Lee, Product Manager, Video Search