Video Editing : Manipulating Time

Bill Davis
September 2005

As video producers, it's our job to make time fly. Or crawl. Or hop, skip, or jump. Given the tools any modern editing software has today, we can pretty much make time do our bidding. Yes, every time we sit down to edit, we are time pilots. We can slice and dice time. We can take a scene that originally occurred in "real time" and slow it down to make it easier for our audience to examine the passing scene in detail. Or we can choose to accelerate time, compressing long seconds, minutes, or even hours into a shorthand stream of imagery. So given this power, how do you decide whether or not it's a good idea to mess with nature's "real time" standard? Tough question.

Typically, shooting a minute of footage takes a minute to play out on screen. It's a natural pace that reflects what we expect to see in the real world. But back in the edit suite, time is (quite literally) what you make it. In fact, the very basic idea of editing starts out as just a form of compressing time. When we cut from one scene to the next, we're removing the time it took to move from location to location, angle to angle and we're compressing the scene into visual shorthand. Hopefully, a scene that keeps our audience engaged by deleting material that is not pertinent to the story we're telling.

So the basic tool of time compression in video production is the cut. In fact, in nearly every movie you watch the only transition employed is the cut. And where and how you cut really matters. Watch well edited material and spend some time analyzing the cuts and you'll find that there's a language of the cut. Particularly in narrative video storytelling. You can lose your audience if you make a cut that jars the audience out of your story.

In video production terms this is sometimes referred to as a "jump cut" which is two similar shots cut together with a jump in continuity, camera position or time. It's jarring because it messes around with our expectations of time.

If a character raises his arm in one shot, and you cut to a second shot where his arm isn't raised, we say there's no "continuity" which is a fancy term for maintaining visual flow so that the audience sees a proper progression of time between actions. But since the goal of a lot of editing is to shorten time, how do we accomplish this? Trickery, of course.

One technique is to cover our jump cuts with "b-roll" scenes that distract the audience from the discontinuity. This is why good "coverage" or shooting extra scenes that can be used as cutaways is so important. Cutaway shots mask jumps in time.

But sometimes, changing time is really about changing time. Making your scenes faster or slower than they naturally occurred. And there are some great new tools built into our editing programs that make this a lot more convenient than it ever was before.

A couple of generations of software ago, the cool new capability was "time remapping." With this process, the user doesn't specify a single percentage of "faster" or "slower" for an entire clip, but takes the speed change capability to ramp up or ramp down speed changes via keyframes. With this new development, we saw a sudden rash of television commercials hit the air with moving scenes that began with one speed, then smoothly accelerated and decelerated all in a single effect.

It's a cool visual. And today, many editing software programs come with this effect. (check your manual under "time remapping" or a similar term to see if your program can do this.) Again, the advantage is that you control the rate your scenes play out to your audience.

Let's say you're making a "tour of our school" video. At the end of the "here's the cafeteria" sequence, you plan to change scenes to the "here's the band room" sequence. Instead of shooting the cafeteria sequence, then turning off the camera and walking over to the band room to shoot that next sequence, just let your camera roll as you follow your subjects walking from one location to the other. Using time remapping, you can accelerate the footage of the "walk" so that the audience goes along on the trip between the buildings in hyper-speed! This gives the audience a better sense of the physical layout of the school while still avoiding the boredom of a long, slow walking shot.

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