You hold the copyright to a movie, short film, etc. once it has been put into a fixed form as the creator, however actually registering that copyright provides additional protection against infringement.
The Copyright Act defines “motion pictures” as “audiovisual works consisting of a series of related images which, when shown in succession, impart an impression of motion, together with accompanying sounds, if any.” 17 U.S.C. § 101 – which  includes TV Shows, video games, animation, videos, and similar types of works .

The Copyright Act further defines “audiovisual works” as “works that consist of a series of related images which are intrinsically intended to be shown by the use of machines or devices such as projectors, viewers, or electronic equipment, together with accompanying sounds, if any, regardless of the nature of the material objects, such as films or tapes, in which the works are embodied.” (17 U.S.C. § 101).

In the event someone does infringe upon your rights as a creator, the attorneys at Arrington & Phillips, LLP can help you seek statutory damages in both domestic and international matters.