Hi
While it's not possible to have the movies in its own categories at the main menu, one possible alternative is to use the custom movie data .nfo file (as Michell suggests above) in the following manner:
use the <genre> tag in the nfo file to identify each directory (i.e "CategoryA")
Then when using Mizuu, click on the Genres tab at the top and choose your video directory. Only videos in that particular directory or category will be displayed.
As an example, if you had videos of birthdays for several family members and your directory structure is:
Birthday
¬ NameA
¬videoA
¬videoB
¬ NameB
¬videoC
¬videoD
Then, when you create the .nfo file for each video, use:
Birthday
¬ NameA
¬videoA in .nfo file <genre> Birthdays, NameA<⁄genre>
¬videoB in .nfo file <genre> Birthdays, NameA<⁄genre>
¬ NameB
¬videoC in .nfo file <genre> Birthdays, NameB<⁄genre>
¬videoD in .nfo file <genre> Birthdays, NameB<⁄genre>
Now you will be able to display videos in the categories you wish, choosing all videos within the Birthday directory or only videos for a certain Name.
Hope this helps
Cheers!