I just have the default unknown/undefined category, but I don't see anything in the mythvideo setup screen, nor in the individual file info panel on how to create a new category. The online doc and the tarball README are also completely unilluminating.

So what's the secret?!

I absolutely must organize these 350 video files, otherwise the WAF goes way way down.

There may be a better way but this is how I did it.

Adding categories through MySQL, the easiest way is probably through Webmin (there is a thread on Samba which can tell you how to start Webmin.)

Log into Webmin
Select Servers Tab
MySQL Database Server
mythconverg database
videocategory table
Select 'View Data'
Select 'Add Row'
Leave intid field blank and fill in your categories.

not sure if this is what you're after but I just did:

1. press I to get the menu
2. switch to "View by Folder" mode

Then just tidy up all my files in /myth/video into folders.

I noticed that you can add categories and assign each file to a category when using Video Manager. However this doesn't seem to be very fruitful unless I've missed something.... like a "filter by category" option.