Mobile Web Compatibility Oct 19, 2012 – H.264, navigator.platform, Spade, Phony

Here’s what’s new in mobile Web compatibility this week.

H.264 video playback

Maire Reavy (media product manager) provided a list of video sites to test for video playback compatibility. Aaron Train has bucketed them as follows:

H.264 video that’s working

  • Metacafe (Desktop site served)
  • (Mobile site served)
  • Ovguide (Mobile site served)
  • Vevo (Mobile site served)

H.264 video with issues

  • (Mobile, but don’t see any video)
  • ustream (Mobile site served, should be H.264 but don’t see any video playback)
  • Veoh (Mobile, H.264 offered but video content downloads rather than plays)

Flash video

  • Hulu (Desktop only site)
  • (Desktop site served)
  • (Desktop site served)
  • (Desktop site served)
  • (Desktop site served)

Silverlight video

  • Netflix (Desktop only)

The current focus of our video playback test effort is Advanced Video Coding (AVC) profile support across different devices and operating systems. You can track progress on the Mozilla QA H.264 wiki page.

You can contribute by filing a bug when you encounter an H.264 video playback error or a message that H.264 is not supported in Firefox.


Firefox OS does not include any operating system identifier in its user agent string. Gervase Markham provided a detailed explanation for this decision. It follows from this explanation that Firefox OS should not expose itself to Web clients in any manner. Therefore, navigator.platform will return an empty string when called on Firefox OS.

Any comments on this function can be directed to bug 801614.

Spade update

Clint Talbert and the A-Team made some notable progress on Spade, an automated tool to analyze CSS property usage and UA sniffing practices on the Web. Spade completed a test run of 100 sites, which is 10x the previous test run size. The A-Team is continuing to work on running this tool at Web scale with a short term goal to analyze the top 500-1000 sites on the internet.


Matt Brubeck has updated the Firefox for Android Phony add-on, which allows you to change the UA served by Firefox, to include the Firefox OS UA as an option. With this change, you can now use your Android device to test the impact of UA sniffing on the content served to Firefox OS.

About Lawrence Mandel

Firefox program manager
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