Adding home video to Apple TV Home Video section for Home Sharing

how do you add content into the library? I try to drag and drop - doesn’t work.

1. Drag-and-drop should work [as it does for me]. First click one of the Library categories in the side bar. Then drag-and-drop when you have this Library view active. Drag-and-drop your compatible .mp4/​.m4v/​.mov file to the main window. Before you let go of holding with the drop action, it should show a blue outline of the main library content part of the window, as a sort of confirmation that the files with this suffix are usually supported. File tags may be used for the category sorting: files tagged as Movie will show in the Movies section of the Library, even when dropped to a different Library category (like Home Videos), and vise versa. Some empty Library categories may be hidden, until a video for that category gets added. To show more (or less) categories, use the Edit option next to the word Library in the side bar; only visibly when hovering the mouse pointer there. Then check or uncheck categories as wanted.
2. Or: use the Import option in the File menu, instead of drag-and-drop.

.mov was originally Apple’s preferred filename extension for videos for the QuickTime Player application.

While inspired from the word ‘movie’, it does not matter for the categorizing as Movie, nor tagging as Movie.

Videos for the TV App Library take their category (Movie, Home Video, TV Show) from the Media Kind tag. This can be changed for unprotected videos once a video is in the TV app, or it can be changed by third party tagging apps before (re-)adding to the library.

Home Sharing is accessed on the Apple TV box through the Computers app, not the Apple TV app. You add content to the library in the Apple TV app or iTunes app on Mac or PC, and then it is home shared to the Computers app.