Large object support is for Text & AFP documents, so you won't want to use it for your User-Defined files.
Honestly, I don't think CMOD is a great place for these files due to their size. CMOD is better at efficiently storing billions of small documents than it is storing enormous audio/video files. The closest thing I can say I've done is storing MP3s of telephone calls from a call centre -- but even the largest of those files was only 10 to 20 megabytes in size.
If you have a Content Manager instance inside your company, you may want to store it there instead -- I've heard that large media companies (or huge companies with large media departments) are using CM for archiving this sort of data.
However, if you're locked into using CMOD for this, increase the compressed object size under the Application Group definition to the maximum (99999), and set the compression type to be 'disable' in the Application.
Please report back and let us know how it goes!
-JD.