I wonder how the app determines what users should see a video. If someone post a clip playing guitar and singing for example, would it determine this is a perf

I wonder how the app determines what users should see a video. If someone post a clip playing guitar and singing for example, would it determine this is a performance, and it should show it to cohorts who have liked viewing performances in the past? Or would the AI model work more like… show (unknown type) clip to random people, identify similarities in the people who like or dislike the video based on those user’s viewing habits and then try to identify the video type based on that knowledge? I guess the second method would be very inefficient unless combined with some feature extraction and metadata / tagging from the source. Not an ML person, just a curious dev.