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How Google Plans to Cut YouTube Video Loading Delays

By Wesley Fenlon

Google wants every YouTube video to begin playing instantly (of course, there are still pre-roll ads). Here's how they're doing it.

200 milliseconds. That's the amount of time that needs to pass--between clicking the "play" button on a video and seeing the action happen--for it to appear instantaneous. At least, so says Google. The problem: YouTube isn't instantaneous right now. There's lag time between clicking play on a video and that video beginning. Lag which can be frustrating when a video is only a few seconds or minutes long. Gizmodo's got the story on how Google's engineers plan to cut that lag down to an imperceptible size.

Image credit: Flickr user grahamsblog via Creative Commons.

The first step towards lag-free playback came in April of 2012, when Google overhauled how it delivered multiple video resolutions. All videos are now one file that can be dynamically switched between, from 1080p down to 360p, with quality degrading or improving to match. Before, each resolution was its own separate video file, and switching between resolutions naturally introduced a nasty bit of lag. Google claims the change has reduced video rebuffering by about 40 percent.

When you click on another YouTube video, the updated version of the site will no longer have to reload the video player.

Next comes preloading. In a future YouTube update, Google plans to speed up the data it loads in a couple key ways. First, it will load a YouTube webpage and the video player simultaneously, which will speed up how quickly the video itself can start playing. More importantly, when you click on another YouTube video, the updated version of the site will no longer have to reload the video player. It will keep that data, meaning it can almost immediately start loading the next video you want to play.

Assuming, that is, you tend to watch multiple YouTube videos in a row, instead of following a link from Twitter and then closing the page. If you do that, you'll miss out on Google's biggest speed boost coming to YouTube, which is preloading the first chunks of videos they think you'll be watching next. Just like Google's Instant saerch, YouTube preloading will load up the first parts of suggested or related videos in the background. If you click on one of those, the player won't have to re-load, and the video will already be partially loaded. There's some real speed.

Check out the rest of the story to see how you can check out preloading right now--the feature is currently being tested on Android, but we should see it on desktops within a couple weeks.