I have seen words such as filmo, filmeto, video, videaĵo, but people tend to disagree about what is correct or not. Is there a general consensus between dictionaries about the definitions? Can you call all these units from YouTube with a unique term, or does it always depend on the kind of content (movie, music, infographics) presented?
A filmo is a collection of images which can be shown (cf. the technically a bit outdated definition by PIV).
video is the technical electronical managing of images (and sound), see PIV.
So, the word you are searching is filmo (and filmeto when you mean a short movie). Usually you won't need the word video unless you're talking about technical stuff like editing a movie. The use of video in the meaning of filmo is probably motivated by similar words with a broader meaning in ethnic languages. The word muzikvideo, however, seems to b popular (at least it has got a Wikipedia article).
Of course, the word videaĵo, meaning "something produced by video" is OK, but it may put an accent on the technical side that most people probably don't feel.
I'll preface this by saying that I choose not to Esperantize brand names; I find it's much more practical from the reader's side to just see the word itself, with an Esperanto suffix if necessary (e.g. Mi ŝatas YouTube-on)
With that said, I'd simply suggest YouTube-aĵoj. If more precision were required, while still getting the "YouTube" point across, I'd say something like YouTube-a video/filmo.