Artists' film and video is often divided in terms of its exhibition possibilities between the gallery and the cinema.
Two very different spaces that each have their own distinct infrastructures, cultures and audiences which can have a significant effect on your work and the way it is seen. This is why it is important to consider how your work will be shown when you are planning it. Some work is robust enough to be able to be shown in both spaces, and can find new meaning in each. However most work is ultimately better suited to one or other space. Ideally this end exhibition format should be an integral part of the work and part of its concept. Cinemas are better suited for works where seeing it from beginning to end is important to its understanding and they invite a more intense engagement from a usually captive audience. The downside is that audiences usually have to pay to get in and it may only show once in a particular venue. Galleries usually offer a more extended showing either with works on a loop or timed screenings and great potential for audiences to interact spatially with the works, however it is difficult to get audiences to watch complete works in this environment, especially long works. So think about what's right for your work.
Of course, there are other more non-traditional spaces that might be worth thinking about too, for example, the artists' group, Housewatch specialised in using light, film and sound to transform urban environments with works such as Cinematic Architecture for the Pedestrian (1985).