The State of HTML5: Firefox Now Supports MP4!

Blog 2 min read | Aug 12, 2013 | JW Player


With Q2 of 2013 behind us, it is time for another update of our State of HTML5 Video report. The last few months have mostly been about filling in the gaps, with Android improving its API support, Opera adding Fullscreen support and Internet Explorer 10 slowly replacing IE8 and IE9. The biggest story though is Firefox’s phased rollout of MP4 playback support.

MP4: One Format That Plays Everywhere

Those following the HTML5 news have known for a while that MP4 support in Firefox would be coming. CTO Brendan Eich explained Mozilla’s reasoning (mobile!) in an elaborate blog post last year. Spread out over the last few releases, MP4 playback indeed arrived on several platforms. Below is an overview, taken from the Mozilla Developer Network, together with some Statcounter market share data:

Operating System

Market Share

Firefox MP4 Support

Windows 7


Yes (Firefox 21)

Windows XP



Mac OS X



Windows 8


Yes (Firefox 21)

Windows Vista


Yes (Firefox 22)






Yes (Firefox 20)




All in all, some two thirds of the Firefox install base can now play MP4. Work on MP4 support for the remaining one third (Windows XP, Mac OS X and Linux) is still in progress. When that is done, Firefox can reliably play MP4 across platforms.

Even at present though, Firefox’ support makes MP4 the undisputed single format to use for playing online video: some 80% of the global browser market now play MP4 in HTML5, with the remaining browsers playing MP4 in Flash (Internet Explorer 8) or through built-in media players (mobile browsers like Opera Mini).

WebM: Moving On To New Applications

So what about WebM then, that other web video format that Google launched in 2010? Is it useful to encode your video content in WebM? From a pragmatic point of view, it doesn’t make much sense:

Of the roughly 20% of the market not supporting MP4 in HTML5 mode, only some 5% would be supporting WebM in HTML5: Firefox users on not-yet-supported platforms and Opera users.

WebM by itself would cover only some 60% of the market. Since Flash (or Silverlight) doesn’t support WebM, a fallback strategy would not help boosting this number.

From an idealistic point of view though, WebM is royalty free – it would be a shame if the format just faded away. Luckily, WebM continues to be relevant in other areas, most notably WebRTC. This is a W3C standard for browser based Real Time Communication (think Skype, iChat, Hangouts), for which WebM is the sole video format. A cool new application of WebRTC and WebM is the Google Cast API, which enables real-time browser tab sharing to TV’s using an inexpensive WiFi dongle. Expect us to write more about that soon!