Playing well with Windows 8: Will other browsers work with the new OS?

While both Mozilla and Google have announced plans to integrate their browsers with Windows 8, and Opera Software is considering doing the same, actually making assimilating the two may be a whole new challenge for developers, with a few new constraints thrown in for good measure.

Browser makers are facing a different hurdle when building for Windows 8 as compared to previous Microsoft operating systems. Essentially, the software giant has included two user interfaces in Windows 8, based on the new Windows Runtime. The "desktop" UI displays applications with the familiar chromed look, as seen currently with Windows 7-based apps. The "Metro" UI, on the other hand, runs in a full-screen chromeless mode and is optimized for touch. Windows 8, which is now available for testing as a "consumer preview," supports those two browser experiences in the form of Microsoft's Internet Explorer 10 browser. Essentially, IE 10 is available as two separate browsers supporting two different UIs in Windows 8.

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Windows 8 and its power-saving promise

Windows 8 users might expect to use other browsers than Internet Explorer 10, and it seems that Microsoft will allow it, except that earlier IE browsers (such as IE 9, etc.) won't be allowed to run on Windows 8, according to Microsoft's IE 10 FAQ. Other browser makers, such as Mozilla, Google and Opera, that are building for Windows 8 can do so, but they face certain requirements. For instance, they have to build something called a "Metro style enabled desktop browser," which is a Microsoft term encompassing certain specs for Windows 8-based browsers.

Metro-style enabled desktop browsers

Despite the "Metro style enabled desktop browser" terminology, a Microsoft white paper (Word doc) on the subject indicates browsers built to this spec will support for both desktop and Metro UIs. The catch is that Metro-style enabled desktop browsers have to be the default browser to work on the Metro side.

A blog post by Mozilla Firefox developer Brian R. Bondy confirmed that the new Firefox browser being developed for Windows 8 can only run in the Metro mode if it is set as the default browser. He added that "this is a decision made by Microsoft." No technical reason was given.

Microsoft, for its part, claims in its white paper that this arrangement with the default browser setting requirement works the same as it did with Windows 7 -- that is, a default browser needs to be specified. However, the Metro UI is a new addition to the operating system in Windows 8, and staying true to that experience also seems to be a reason for the default browser restriction, according to Microsoft's white paper.

"A Metro style enabled desktop browser can be thought of as a desktop browser that can also participate in the new Metro style experience," the white paper explains. "The restriction to limit Metro style user experience participation to the user's default browser is rooted in preserving the Metro style user experience. Note that this limitation applies to all browsers, including Internet Explorer."

Bondy was uncertain whether Mozilla's future Firefox Metro-style enabled desktop browser would be available through the Microsoft Window Store "since it is not of Metro application type." Mozilla also may have to drop its ban on the use of Microsoft's ActiveX multimedia feature (a frequent security concern) because a Windows 8 requirement is to have ActiveX support included in apps, he noted.

Google affirmed to Computerworld author Gregg Kaizer that it is building a version of its Chrome browser to work with Windows 8, saying that "we're in the process of building a Metro version of Chrome along with improving desktop Chrome in Windows 8, such as adding enhanced touch support."

An Opera spokesperson told Computerworld that "we are currently looking into Windows 8" but would not confirm that it was building a browser to support it. An Opera Software blog in September showed screenshots of Opera running on the developer preview version of Windows 8.

H.264 video codec support

Mozilla could be changing its mind on video codec support in Firefox. The organization might be looking at adding H.264 video codec support, for instance. Andreas Gal, director of research at Mozilla Corp., brought up this topic in a Mozilla developers platform discussion, although he noted that he doesn't have the sole authority to make such a decision.

Mozilla's reconsideration may stem, in part, from Google's actions. Apparently, Google never withdrew support for H.264 in its Chrome browser, even thought it promised to do so about a year ago. An Apple Insider article makes the claim that H.264 is still supported in Chrome. No reply from Google was received at press time to confirm whether that claim is true.

Google announced plans to drop H.264 support altogether in its Chrome browser in January. That move was a shot at MPEG LA, a group of patent-holding companies that includes members like Apple and Microsoft -- all having intellectual property associated with the H.264 video codec. MPEG LA had targeted Google's VP8 for legal action, asking its members to check if their patents were infringed by it.

Google's substitute for H.264 was its WebM project, which would support an open video codec based on Google's VP8. Mozilla and Opera both favored the VP8 and Ogg Theora codecs and did not support H.264. However, if Google did not drop H.264 support in Chrome, then that might explain Mozilla's rethink on the issue.

Hardware vendors, independent software vendors and browser makers have to pay royalties if the patented H.264 technologies are used in their products. However, individual users aren't being charged for using H.264 technology to view Internet videos, which is an arrangement that MPEG LA stated (PDF) would last through the life of MPEG LA's license.