According to the Section 110 (1) of the U.S. Copyright Act, the performance or showing of films in the classroom (or a similar venue) as part of “face-to-face” teaching at nonprofit educational institutions (such as Pitt) you are free to display and perform any copyrighted work so long as it meets the pedagogical purposes of your course. The viewing should be limited to only students participating in your course.
One important additional criteria is that the copy of the film that is screened has to be legally acquired e.g. a copy that you purchased, borrowed from the library. This means that you can not use a bootlegged or pirated copy.
Going beyond films, there are no restrictions on the type or length of work you and perform and display. This means you can show a full-length movie, play a full recording of a song, perform arias, read poems, and act out scenes from a play without a license as long as it's within the classroom.
See the Association of Research Libraries (ARL) “Performance of or Showing Films in the Classroom” for further advice and examples.
Distance education is covered by §110 (2), also known as the TEACH Act, which is significantly more restrictive that the face-to-face teaching exemption.
For online courses, there are three options for displaying and performing copyrighted works: meeting the requirements of the TEACH Act, asking permission (getting a license), and fair use.
Below we describe the requirements of the TEACH Act:
There are two major limitations in the TEACH act. First, the use of “dramatic"* works is restricted to “reasonable and limited portions” which means that, for example, you cannot show an entire copyrighted film like The Avengers or Arrival in your online class unless you can show that doing so is "reasonable and limited."
The second limitation is that the use of works specifically created for online or mediated education cannot be used under the TEACH act. (You can still use them by getting permission or a license from the copyright holder or if your use qualifies as a Fair Use)
If the work is a non-dramatic literary or musical work you can utilize the entire work in your class.
Unfortunately, the TEACH Act includes additional requirements:
The performance or showing of films, videos, and TV programs in a similar venue (i.e., not necessarily a classroom) for face-to-face teaching is still covered under Section 110 (1) of the U.S. Copyright Act.
The the display or performance must still meet the pedagogical purposes of your course and be limited to those participating in the course.
The display or performance cannot be open to the public or freely available via the Internet.
The main point here is that the venue for teaching does not have to be limited to a traditional classroom. However, the film's use for teaching or educational purposes does need to follow the parameters set out by the Copyright Act.