Video Editing : Manipulating Time (page 2)

"Slow-mo," or "slow motion," is a powerful technique used to help your audience "get" a scene where the action happens too quickly for the brain to process.

A great example is the Matrix movies' "bullet time" effect to focus audience attention on the main character's supernatural abilities. That type of visual time remapping was revolutionary when it hit the theaters some years ago. Today, most edit systems can slow time down with a few clicks. However, it's important to realize that not all "slow motion" effects are created equally.

Most stock editing software simply change the rate at which the frames display to achieve slow and fast motion effects. So changing speed in even increments-- frames halved, doubled, tripled, etc. is pretty easy for any edit software. But what if you need something other than this type of mathematically simple time manipulating? What if you want to slow your scene down by 40%? Clearly, the math necessary to divide those frames down is much more complex.

That's where the computer wizards have had to step up and create mathematical models to do something complex called "interpolation." Interpolation is the process of analyzing the motion data in the video frames on your tape, and not only displaying them at varying frame rates, but actually "faking" data that didn't exist on the original tape in a way that fools the viewers eye into believing that the slow or fast motion on screen is both smooth and realistic.

Good interpolation algorithms are at the heart of getting really good results in re-mapping time for fast or slow motion effects. So if you want good results, make sure your software has the power to interpolate time.

Like every other video and editing effect, time remapping is at it's most powerful when it's used to mean something other than just "look at this -- this looks cool." In the Matrix it reveals character. The "bullet time" sequences help us visualize things that in real time would be a blur -- and in our "school tour" example, time remapping lets us keep the pace of our video interesting while still letting the audience see the campus -- a core goal of the video.

So dig out your manuals, and learn about how your software can turn you from "video editor" into "time pilot" with a few clicks. You might be surprised at all the great places you can show your audience once you learn to how to fly! Bye now, I've run out of time.

Bill Davis writes, shoots, edits, and does voiceover work for a variety of corporate and industrial clients

We often think of time manipulation as reducing time, such as in our school tour when we moved from the cafeteria to the band room. All that video in between the two locations would have been boring to watch at real time, and would have wasted time needed for other more compelling shots. So we simply deleted the walk, or in this example, we sped it up to make it more interesting. But what if we want to drag a scene out that takes only milliseconds to actually occur. Ah! There's the rub!

The 1984 movie The Natural, starring Robert Redford, is full of classic examples of expanding time. How long does it take a baseball pitcher to throw a pitch to the batter? At 80-miles-per-hour, about 1/3 of a second. How can you expand this shot to add more drama to the scene? Time Manipulation. In the movie, we see Redford getting ready for his wind-up pitch. We then see a wide shot of the pitcher's mound as he analyzes the situation. We cut to a reverse shot of the batter, catcher and umpire. Cut to a closeup of the catcher giving a secret signal to Redford. Cut back to a closeup Redford's face as he nods to the catcher. Cut to a wide shot of the breathless spectators in the stands. Cut to a close up of the small boy watching his hero. Cut back to the pitcher as he raises his leg for the windup. Cut back to a close up of the batter as he kicks the dirt at home plate. Get the picture? This entire sequence plays out to be about a minute or longer before Redford actually throws that lightening fast pitch. We editors are the masters of time manipulation!

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