Netflix switches from Silverlight to HTML5 in Windows 8.1, reduces CPU usage dramatically

With the release of Windows 8.1 Preview, Netflix now supports streaming over HTML5 instead of Microsoft's proprietary Silverlight plug-in. The caveat is that only Internet Explorer 11, which is bundled with Windows 8.1, supports the necessary HTML5 extensions; if you're a Firefox or Chrome user, you'll continue to use the Silverlight plug-in. In our initial testing, the switch to HTML5 sees a massive reduction in CPU usage -- about one third of Silverlight's CPU usage.

Despite the massive shift away from Flash, Silverlight, and other third-party plug-ins for dynamic web content, content producers providers have steadfastly refused to shift to HTML5 due to a lack of DRM. Whether we like DRM or not, the sad truth is that streaming services such as Netflix and Hulu, which are massively popular, only exist because the license holders feel somewhat secure that their shows won't be ripped off. The conventional way that HTML5 video is implemented is basically by putting an entire, unencrypted video file on the web, and then embedding it on a web page. This file can be directly downloaded if you so wish. This is fantastic for surfers and the proliferation of the open web, but not so great for copyright holders.

To bring streaming TV and movies to IE11 and HTML5, Netflix has been working with Microsoft to implement three extensions to HTML5 dubbed "Premium Video Extensions." These extensions, proposed by Microsoft, Mozilla, Google, and Netflix, aren't currently part of the official HTML5 spec, but have been submitted to the W3C as working drafts. In general, with HTML5 being such a young spec, the last few years have seen browser makers implementing their own subset of HTML5's features in an unordered fashion. Microsoft is taking the lead with the Premium Video Extensions, but it's still behind Firefox and Chrome in other areas of the HTML5 spec. With Mozilla and Google both involved with the working drafts, it wouldn't be surprising if the same extensions also come to Firefox and Chrome in due course.

There are three parts of what Netflix calls the Premium Video Extensions: Media Source Extensions (MSE), Encrypted Media Extensions (EME), and the Web Cryptography API (WebCrypto). MSE allows for JavaScript to handle the creation of manipulation of HTML5 <video> and <audio> elements; in essence, rather than just loading a complete video or audio file, JavaScript allows for adaptive streaming, time shifting, and other useful features. EME, as the name suggests, allows for multimedia to be protected by DRM. WebCrypto isn't directly related to content streaming, but the ability to easily and securely pass data between browsers and servers is a valuable feature.

In our initial testing, the HTML5 version of Netflix looks a lot like the Silverlight version, except that it's a bit flatter and plainer (not necessarily a bad thing). Movies and TV shows still load just as quickly, video quality is the same, thumbnails still pop up when you mouse-over the playback bar, and you can still jump through the stream with minimal loading. Best of all, the HTML5 version of Netflix seems to use significantly less CPU time than the Silverlight version. As you can see in the screenshot above, IE11 (left) uses just 1.6% of my CPU, while Chrome 28 (right) uses 5.4%. This is with a beefy, Core i7 930 CPU clocked at 3.8GHz; on a mobile device with a smaller CPU, the difference could be a lot more noticeable. There are potentially huge battery life gains to be had, if you use Windows 8.1 and IE11 to watch Netflix videos.

You may also notice that IE11 is blacked out in the screenshot. I'm not entirely sure why this is -- it was certainly showing video on my monitor -- but it could be part of the DRM measures taken by Netflix. There's no word on when Netflix's HTML5 player will come to Firefox and Chrome, but we wouldn't be surprised if it's fairly soon. If you listen carefully, you can hear the gurgling death wail of Flash and Silverlight.