Netflix to dump Silverlight, Microsoft's stalled technology

Shifting to HTML5, first on Chrome OS, then Windows and OS X, for in-browser video streaming

Netflix on Monday said it would abandon Microsoft's Silverlight media player plug-in for Windows and OS X in-browser video streaming, and replace it with a trio of HTML5 extensions.

The move will be a blow to Silverlight, the technology Microsoft once aimed as a replacement for Adobe Flash, but that has languished since Silverlight 5 shipped in December 2011. Because Microsoft has never publicly committed to a Silverlight 6, many believe the platform has met its maker.

Netflix tacitly acknowledged as much in a blog post Monday by Anthony Park, director of engineering, and Mark Watson, director of streaming standards. "Since Microsoft announced the end of life of Silverlight 5 in 2021, we need to find a replacement some time within the next eight years," Park and Watson wrote.

As the two noted, Microsoft has said it will support the Silverlight 5 browser plug-in until Oct. 12, 2021.

Netflix is one of the largest licensees of Silverlight, and among the few major services that still rely on it. Although the technology was used by NBC to stream the 2008 Summer Olympics and the 2010 Winter Olympics, the network switched to Google-owned YouTube to provide the streaming infrastructure for last year's London Games.

Park and Watson defended the switch to HTML5 with well-worn arguments, including distrust of plug-ins on security grounds, but they also pointed out that browsers, even on the desktop, are shifting to a no-plug-in model.

Microsoft, for example, has banned plug-ins from Internet Explorer 10 (IE10) on Windows RT, the scaled-down edition aimed at tablets, and on the "Modern" user interface (UI), formerly known as "Metro," on Windows 8. Mozilla's Firefox, while not going that far, now automatically blocks all plug-ins except for Adobe's Flash Player, making the user "click-to-play" a plug-in.

Some users, especially those running Macs, have also criticized Silverlight for hogging their machines' processors, slowing other tasks to a crawl or making their systems overheat.

"Moving to HTML5 is important to someone like Netflix, which wants to be as platform agnostic as possible," said Mike McGuire, an analyst with Gartner. "HTML5 has matured to the point where most in the industry are moving to it."

Netflix's shift from Silverlight to HTML5, said McGuire, is proof of that maturation.

Park and Watson said Netflix would replace Silverlight on Windows and Mac desktops and notebooks with three HTML5 extensions -- Netflix collectively dubbed them "HTML5 Premium Video Extensions" -- to allow JavaScript to generate media streams, lock down the content with digital rights management (DRM) anti-piracy technology, and encrypt/decrypt the JavaScript-to-Netflix-server communications.

Netflix has already begun using two of the three extensions -- the exception is "WebCrypto," which handles JavaScript encryption -- in Google's Chrome OS on Samsung's Chromebook. Once WebCrypto is supported by the Chrome browser -- the foundation of Chrome OS -- Netflix will start testing the Silverlight substitute on Windows and OS X.

Netflix collaborated with both Google and Microsoft on creating two of the three extensions -- those already in use -- while WebCrypto was a joint effort between Google and Mozilla, the creator of Firefox.

The switch to HTML5 was not unexpected. Netflix already relies on HTML5 to stream video through its mobile apps, such as the one for iOS on the iPhone and iPad, and it's talked about shifting to the Web standard on desktops since at least 2010.

Netflix did not set a timetable for abandoning Silverlight.

Microsoft did not immediately reply to a request for comment on Netflix's decision, or to questions about Silverlight's future.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed. His email address is

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Copyright © 2013 IDG Communications, Inc.

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