What is the maximum video file size for ituneU?
Can iTunesU take HD video files between 3 and 4 GB?
Are any file types preferred? mp4 or m4v
null-OTHER, iOS 11.3.1, iTunesU
Audio and video specifications
Most school networks can be flaky under load, so I would recommend breaking your videos into smaller chunks so you don't have a classroom of students all trying to download 4 GB at once.