The App That Cheats Time

Some of the coolest slow-motion videos you've ever seen have a secret: They aren't quite real.

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By far the most memorable shot in the BBC/Discovery Channel series Planet Earth was the one with the shark. You know, this one:

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This footage was shot with a camera that costs more than a car. (Incidentally, one of its most common uses is to capture crash test footage.) This next video, on the other hand, was shot with a camera that costs about $700:

The secret is a piece of software called Twixtor. A plugin that works with most major video editing suites, Twixtor can re-render regular video, usually recorded at 24 to 60 frames per second, into 100, 500, 1000, or even 10,000 frame-per-second super-slow-motion. "When you can, use a camera with a higher framerate," says Pete Litwinowicz, cofounder of RE:Vision Effects. "I always say that. But there are times that you can't."

Ultra-slo-mo cameras are exceedingly expensive, but also have a unique set of limitations. Shooting in 1000fps under artificial light can result in flickering; shooting without enough light will leave the image almost pitch black. Twixtor works with video from any camera, and comes pretty close to matching the real thing.

RE:Vision came into existence after Litwinowicz met Pierre Jasmin, a special effects expert who helped develop the icon "bullet time" effect used in The Matrix, while working on a film called What Dreams May Come. One of the film's subtle effects required that every pixel be tracked from frame to frame; the technology they developed for this, they discovered, could be used for a lot of things: image morphing, motion blur, filling spaces, and, of course, slow motion. They released the first version of Twixtor, which uses pixel tracking to guess what extra video frames might look like, in November of 2000.

The plugin gets plenty of professional use — Litwinowicz says Twixtor was used in some of the early Harry Potter films, for example — but it's targeted at a wide market. It's hugely popular among sports cam users, and GoPro has coopted scores of Twixtor-edited videos for its marketing materials.

It's also popular, albeit often in pirated form, among gamers. Game sessions captured with FRAPS or similar software differ from video recorded by a camera in that there's no blur or natural image distortion — two things that make some Twixtored videos look fuzzy or unrealistic. As a result, Twixtor can cleanly slow gaming videos almost to a halt:

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Slow motion is a profoundly powerful video effect, and Twixtor makes creating it both easier and more accessible (It starts at under $200). I asked Litwinowicz if it feels like cheating, or if manipulating time to such an extent feels a bit like playing Video Editor God. He said no — if brightening a video or recoloring a photograph isn't "cheating," and unless the point of the video is to serve as some kind of forensic, perfectly truthful record, then using Twixtor isn't either. And besides, it's not an excuse to be a lazy professional videographer or editor. It's mostly a way for amateurs to punch a little bit above their weight. (Or not: search YouTube for "Twixtor" and you'll find scores of people whose slow-motion attempts look like bad abstract art.)

Sooner or later, though, he expects people to get a little tired of it. "I think eventually it will become, instead of the effect du jour, the effect du yesterday." It's part of a natural evolution of visual language: with wider availability of tools like Twixtor, ultra-slow-motion becomes less of a novelty or an effect than a simple tool.

Contact John Herrman at

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