Free Film School: Tempo
Today were are going to look at a key video concept that is taught at USC: tempo. Three things control the tempo of your film: your editing paradigm, your on-screen action and your music. What do I mean by editing paradigm? Your editing paradigm is the expectation you set up in the mind of the viewer from the edits they've seen thus far. If you take the case of the film "Iron Man", you'll find that most of the action shots run somewhere between two and four seconds in duration. This is consistent throughout the entire film. The audience is trained early on that they need to pay close attention, and they are also comforted to know that scenes will be paid-off quickly. It is a joy to watch a film with a tight and consistent editing paradigm.
You can't do much about on-screen action after the film has been shot, so let's move on to music selection. If you take a quick look at the short film I've prepared for this article, you'll see a chase scene set to the theme music from "Indiana Jones" (composed by John Williams). The music has a very fast tempo (allegro) and is somewhat agitated (agitato). Music that is allegro agitato adds energy to your video, regardless of the video content. If the on-screen action does not fit well with the energy created by the music the result is a visual discord that makes the audience want to leave the theater, go home and write scathing reviews for the New York Times. This is what we want to avoid.
How can we bring the soundtrack into harmony with the visuals? The first rule of thumb is to not attempt to sync your onscreen action with changes in the music. This will draw too much attention to the music. The next rule is to cut out the heads and tails of shots that do not contain action. If your character has exited the frame the shot is probably over. The next rule is to cut a shot once it's provided the information it has to deliver. For example, if your shot ends with a long zoom-out from a character performing a single action (like eating a sandwich) you should cut as soon as the action has registered with the audience. There is no reason to keep zooming-out once the audience gets the idea (they didn't show up to see your camera work, they came to see what the character is going to do after he eats that sandwich). Once you have tight scenes that maintain audience interest you'll find that the music is not noticed as much. Good! Next let's get the music noticed even less by choosing music that has a tempo that matches the energy of your scene. In the example provided the allegro agitato tempo matches the visuals quite well, especially when the alligator is chasing the kids. At the very end of the film the music reaches a crescendo, which provides the audience with a sense of closure. The "crescendo effect" occurs when the music no longer blends into the background. This can be helpful when the music is used to make a very specific point (i.e. the chase is over). When cutting for "crescendo effect" it is possible to let the image sit on the screen past the point of new information. In the example you'll see the kids safely drive away from the alligator (in a single shot that lasts for about eight seconds) while the music reaches its crescendo. If there were a number of quick cuts at this point the images would draw away from the feeling of closure provided by the music. Thus we come to the last rule of tempo, which is that every rule I've described is made to be broken. The important thing is that whatever music you choose and however you pace your shots at the end of the day you need to get the emotional response that you were after.