Text hook

Usually one line, set large, and held long enough to read at scroll speed. Put it in the upper third, clear of the caption bar and the interface. The job matches a title's: say what someone is about to get and why the next few seconds are worth it. It works best alongside the spoken opening instead of repeating it word for word. Length is where people go wrong. Anything you cannot take in at a glance has already lost the viewer it was written to catch.