Man, your app is brilliant and can be used in much more wider aspect than just a media catalog.
If you would add a few easy to program features, the app could be completely customized to different world scenarios:
1. In list view, allow user to edit which fields should be displayed. As example: I use the app as catalog of gym exercises. Folders are different exercise group videos (e.g. progressions, stretching routines, 3rd party exercise programs etc.), albums are specific trainings. Tags are used for different muscle groups, stretch/strength/mobility etc. categories. I use description of video file to add notes to the specific exercises, unfortunately I cannot display them directly in list view, which I miss a lot.
2. Excluding specific files from folder. As example, I have .jpg image in folder just for having nice folder thumbnail, but I don’t need the image itself to be shown in folder.
3. If you would allow user to edit language strings of current namings (folder, album, tag, …), you could create more generic app. In my example, I would for instance rename Albums -> Trainings, Folder -> Exercise group, etc.
I know my request is quite specific, but it could really help your app to be much much more generic than it is now.
Thank you in advance for considering my changes.
Good luck with the app!