I did mention that on a post I edited on the first page of the thread. That I needed to support accented character variants. The manual page you linked isn't specific about whether [:alnum:] includes é, å, ñ, etc..

It does mention that you can use an equivalence class for accented characters, but then also says that the regexp matching in awk doesn't support equivalence classes.

Then there are other characters that are part of foreign alphabets that are valid within filenames which can conceivably be used in the movie names listed on Apple's site. Such as ß, œ and others.

In the future I'd like to break out extended information and full text naming into a metadata file which will be used by the application (SageTV in my case) and can have the filenames completely void of all these special cases. I'm not at that stage of integration yet and will still need to install some mods on my PVR to make use of any metadata files I create.