[shmerl]

Yes it does. Mozilla couldn't avoid using H.264 in Firefox OS because VPx hardware decoding isn't widespread yet (though it catches up in the newest SoCs). But it uses the capability of the underlying system. I don't think Mozilla licenses anything from MPEG-LA.

[vetinari]

Newest SoCs as in we are already on second generation with support? OMAP4 and Tegra2 supported it years back.

Today, almost all SoCs support it, from Exynos to Rockchip. Notable SoCs that do not support VP8 are Apple's Ax. Not that it is a surprise.

[shmerl]

Availability in SoCs is paired by actual deployment of those SoCs to end user devices. The majority of currently available end user devices don't have hardware VP8 decoding yet. As time goes by and newer SoCs push out older ones this will improve, but we aren't there yet.