Adding metadata to m4v without iTunes

I want to add the file name of a m4v to the metadata of the m4v before it is imported into iTunes. I have been unable to find a third party program that will do this specific tag and I though there might way to do it directly with applescript. For example I would put the name Stargate.SG1.s1e1.dvd.m4v in the comment field.

I indicate the source of the show in the filename (bluray, DVD or EyeTV for example) and I want to be able to do information with this in iTunes later. iTunes renames the files after it imports it so I can’t exactly us iTunes .

It looks like Quicktime might have had this capability at some time but I can’t find the documentation now.