You would think that people would just normally choose to play a video the way it was intended or meant to be watched. But apparently, one of the most requested features on YouTube is the ability to adjust the speed to how the viewer actually wants to watch it. A few years back, the variable speed playback was actually introduced to the web version, and now, due to insistent demand, it has now arrived on the mobile app version.
If you’re not yet familiar with this feature, basically it just lets you choose whether you want to slow down or speed up the video that you’re watching. You will be able to choose from .25x (quarter speed) up to 2x (double speed), or if you’re feeling a bit normal, still watch it at normal speed. Those watching long lectures or interviews sometimes want to speed things up a bit but still discover (even retain) new information. Some also use it to slow down videos to be able to capture details, like in a cooking tutorial or figuring out the moves in a choreography.
Because YouTube didn’t want to give you the chipmunk effect when speeding up or the weird, slow-mo movie voice when slowing down, they used a process called time stretching which lets you change the duration of the audio signal without affecting the pitch or distorting it. They achieved this effect through a phase vocoder, and in particular for Android, the Sonic library for audio manipulation. If you want to know more about the technical aspect of it, you can read about it on YouTube’s blog post (source below).
But in less technical terms, speeding up or slowing down the video that you’re watching on YouTube, for whatever reason that you need to do it, it won’t really sound comedically weird. Well, not as weird as you would expect (still a bit weird sometimes) So try the variable speed playback options now on your YouTube app.
SOURCE: Google