Teaser trailers

I researched into the difference between a teaser trailer and a normal trailer. Here is an example of a teaser trailer:



Only films with a large budgets choose to follow this kind of marketing campaign. The reason for this is to create hype and anticipation. They want the audience to be aware of the fact that there is a new film being made and will be coming out soon. Usually teaser trailers are released while the film is still in production and thus things can changed when the actual film is released.
Teaser trailer are usually much shorter than actual trailer such as the one above only 21 seconds. the reason for this is because the people who are making the film want to give limited amount of what the film is going to be about and to create interest, in some instance these trailers do not give any details of who will star in the film or a release date. the objective of a teaser is to just bring awareness that there is a film being made and to create an audience.