YouTube on mobile finally gets speed controls, but it wasn't easy

Technology has made somethings so magical and so easy that we often take for granted how difficult they are to actually do. Like speeding up or slowing down a video. We have apps that let us do that anyway, so why can't YouTube? The good news is that the engineers over at YouTube have finally solved the puzzle. The even better news is that this variable speed playback feature is finally available on mobile as well.

Changing how fast or slow a video plays is relatively easy for videos already stored on local storage. When streaming a video, however, there are a lot more factors at play. When streaming a video on mobile devices, you have to account for even more limits compared to a desktop.

For the video's audio, YouTube has to take one important side-effect of variable speed into account. When you speed up or slow down audio, there is a natural tendency for the pitch to rise or fall, respectively. YouTube had to implement a form of time stretching, which changes the duration of the audio without affecting pitch or adding distortions.

The video itself is even harder to pull off. For one, the frames of the video has to keep in sync with the audio. Complicating matters is the fact that mobile devices might not always have a reliable Internet connection or might not have enough processing power to decode the video at the right frame rate.

But that arduous challenge is now over and YouTube is finally able to rollout variable speed controls for mobile. That's for both Android and iOS even. So go ahead and enjoy some slo-mo dramatic chipmunk look.