Instagram Reveals Stunning Tech Behind Its New Hyperlapse App
Image: Mashable, Christina Ascani
Instagram released a new app this week called Hyperlapse, an app that makes it simple for users to create seamless iPhone or iPad.
Now, Instagram is offering a look at how the app was built from a technical perspective on the Instagram Engineering Blog.
One of Hyperlapse's lead engineers, Alex Karpenko, describes how the team could successfully create time-lapses with a smartphone without needing a steadicam mount.
It requires a good deal of video stabilization. Karpenko developed an image stabilization technology called Cinema, which uses the phone's built-in gyroscope to measure camera movement. An algorithm can then be applied to those measurements to reduce shake and create fluidity.
The algorithm works by sending samples from the gyroscope and frames captured into a stabilizer, which then outputs a new set of 'correct' camera orientations. Those orientations are then sent to a stabilization filter, which puts out the steady frame.
That final result removes the jittery movements and bumps of a traditional unstable recording.
This is a smart idea - and something that Karpenko developed as part of his thesis at Stanford University.
This video lets you see how the algorithm crops and zooms footage to create a buffer around the visible area; it also shows very clearly which part of the video is being 'captured' as part of the Hyperlapse. This process is known as adaptive zooming, letting Instagram crop and zoom information in a specific region based on how much shake exists in the video.
One of Hyperlapse's coolest features is that you can use a slider to set the time-lapse level for a video. A 6x level means that every sixth frame is plucked out of the video and played back at 30 fps. Thus, your video is now 6 times faster than the original.
To do that, however, requires some complicated work on the back end.
Karpenko describes the various steps the app must take in real time every time a user scrubs the slider. The kicker? It has to happen without interrupting video playback or crashing the UI.
Without knowing the technical details behind the app, Hyperlapse was impressive. But that's kicked up a notch after seeing how much work went into creating and refining the algorithms, and the real-time processing necessary to create the speed of the hyper lapse clips.
It also makes Instagram's decision to launch the app with iOS support - with hopes for Android support once the APIs are available - make a lot more sense. Instagram did some serious heavy lifting under the hood, and a great deal of that engineering benefits from a vertically integrated ecosystem of device and operating system APIs.
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