So far my google-fu has failed me, so I'm hoping someone here can help:
How can I programmatically modify video metadata (specifically in my case, m4v video files)?
I'm most familiar with Ruby and C#, but I can be fairly language agnostic on this -- that is, if there's a specific language that is good at modifying file metadata, I have no problems spending the required time to learn it well enough to accomplish what I'm trying to do.