iTunes video meta data

It looks like there are some hidden meta data fields for iTunes video.
When you buy a movie from iTunes, there are lots of extra fields displayed while searching on AppleTV. If you try to edit the info, the fields aren't there i.e. actors. This becomes very frustrating as the only way to resolve this is with a meta editor which has to rewrite the file. When changing basic info with iTunes, the file is edited in place and is not rewritten. When dealing with lots of movies, this becomes a problem. Also, you want to make sure the original encoding stays intact.