I'd be surprised if you couldn't drop your own gstreamer plugins into Opera's directory on Windows/Mac. You'd be surprised at the hundreds of millions of XP us

I'd be surprised if you couldn't drop your own gstreamer plugins into Opera's directory on Windows/Mac. You'd be surprised at the hundreds of millions of XP users with codec packs installed already. For the remainder Mozilla would just need a nice 'codec not found, go here' dialog like they already have for Flash.