WebGL should be available soon. HTML5 <video> is pretty much dependent on just getting Gstreamer-openmax in the PS3 and that looks like soon also. Unstable means Sony can have it working in developer platforms and Stable release is by next Gnome cycle or Sept 2012.
Originally Posted by http://blog.abandonedwig.info/2012/07/accelerated-compositing-update.html:
I believe it's past time to break the silence here, so what follows is a short update on the progress we've made at Igalia toward 3D CSS transforms and hardware accelerated animation in WebKitGTK+ (otherwise known as accelerated compositing). I'm happy to say that both the initial WebKit1 and WebKit2 implementation of this work have finally landed, and you can try it out now in the latest unstable releases. Epiphany in Gnome 3.6 will include accelerated compositing (smooth animations and fast WebGL), a port to the brand new WebKit2GTK+ API (stability and security), and a new interface.
During this development cycle we'll continue to improve the implementation of accelerated compositing, but we hope to start looking at other rendering and interactivity improvements such as accelerated canvas, a tiled backing store, touch event handling and a threaded scrolling implementation. I'm most excited about accelerated canvas, because of the work we've been doing recently on Cairo GL. The GL backend of Cairo has been experimental for some time and isn't widely distributed, but recently there's been an attempt to increase its performance and to make it more suitable for embedded platforms.
Once we integrate Cairo GL with our accelerated compositing architecture in WebKitGTk+, canvas content can be rasterized directly on the GPU instead of the CPU. For most systems accelerated canvas means better performance and lower power usage. Hopefully, I can land the patches to enable this as early as Gnome 3.6, but I'm still not sure when the OpenGL backend in Cairo will be officially supported.