Since we have concluded video is important for your overall search efforts, I figured I follow up about a recent thread I spotted at Google Groups about the question on if Google supports MRSS as a format for Video Sitemaps.

The quick answer is yes, but it is not so clear from their documentation. MRSS, which is Media RSS, is one of the two formats Google seems to accept. I submitted an MRSS feed as a test and it did realize and label the feed as MRSS, but my feed did have some errors.

Googler, JohnMu, explained in the thread:

So if you have a video sitemap in MRSS format that you already publish, it might be worth trying to submit that to Google as well.

Forum discussion at Google Groups.