Impact of Shot Length and Motion on Cinematic Tempo

Abstract: Tempo is an important part of film, it is used by filmmakers to communicate various feelings and settings through visual media. Through research, we found shot length and motion are what primarily makes the tempo of a film. Further it was discovered that over the last 80 years the average shot length has steadily decreased while the action genre has grown over the last 30 years. With these findings the purpose of this study became to examine how the shot length and motion impact the cinematic tempo in action films. The first part of the study is about trying to estimate the tempo of a film sequence. This was done by finding suitable equations for tempo in films, the equation used needed two parameters to work, the average shot length of the video and its average motion. The motion was computed by extracting motion vectors of the movement from one frame to another, and then calculating the average motion throughout the scene’s entirety. The motion value was later combined with the average time of a shot to get the tempo of the scene. These calculations were carried out on five different actions films, two were extreme cases in regard to their average shot length. The films would later be shown to test subjects, who would answer questions about tempo, feelings, preference, et cetera. The results found from showing the films to test subjects was that shot length was the most important factor in how viewers perceive cinematic tempo. Motion on the contrary did not have as big of an impact. Ideally, we would not have included the extremes regarding shot length when showing the films, as the results would have provided more useful information.