Instagram is lifting the veil on Hyperlapse, one of the company’s first apps outside of Instagram itself. Using clever algorithm processing, the app makes it easy to use your phone to create tracking shots and fast, time-lapse videos that look as if they’re shot by Scorsese or Michael Mann. What was once only possible with a Steadicam or a $15,000 tracking rig is now possible on your iPhone, for free. (Instagram hopes to develop an Android version soon, but that will require changes to the camera and gyroscope APIs on Android phones.) And that’s all thanks to some clever engineering and an elegantly pared-down interaction design.
The insight that powered Karpenko’s algorithms began, like so many other startup ideas, as a phD thesis at Stanford. This was 2010, and the iPhone 4 had come out: one of the first phones that could capture HD video. That sounded terrific, in theory, but cramming such a great video camera onto a handheld device meant that the videos themselves were often shaky to the point of being unwatchable. “They were all just crappy,” Karpenko says.
He knew that image stabilization was the answer, but the technologies of that time, which you’d find in Final Cut and myriad other video editing programs, were simply unworkable for smartphones. Why? Imagine a video clip, taken from a moving car. To even the juddering camera motion, image stabilization algorithms typically analyze a movie frame by frame, identifying image fragments common to each. By recording how those shared points jump around across frames, algorithms can then infer how the camera has been moving. By reverse engineering that motion data, software can recreate a new, steadier version of a film clip. Yet every step in that process requires processing muscle. That’s fine for a movie studio, which has massive computers that crank overnight to re-render a scene. It’s ridiculous for a smartphone.