"This enables users to enjoy fully accelerated H.264 video playback in a web-browser on a large range of hardware including and not limited to AMD graphical processing units with UVD2 (Radeon HD 3200 IGP and Radeon HD 4000 series discrete cards)..."
I'm just trying to figure out if I will be able to enjoy XvBA XvMC benefits ever in a future release on my 780G ...
Afaik, UVD2 can decode two H.264 streams simultaneously which the RS780 cannot.
But UVD version is reportedly new enough to work with xvba-video.
The RS780 can decode two H.264 streams simultaneously: 1 HD (1080p) and 1 SD. In practise, more streams can be supported provided the real-time constraints are respected. Otherwise, you can get frames dropped. This works equivalently to NVIDIA or Intel chips and drivers.
So the 780G has UVD2? Here is more conflicting information
This is what the driver says. IGPs are a mixture of different blocks. The VPU can be UVD2 while GPU could be older graphics core. I believe the chipset would have gained another name than a simple "update" to RS785 if more than the GPU changed.
One of the complications is that there are really about 5 different revisions of UVD out there. The versions get simplifed for marketing into "UVD1, UVD2" but that doesn't really cover all the nuances of what features & programming model are present with each class of GPU.
The UVD block in 780 is, IIRC, an early version of UVD2 which had most, but not all of the features we associate with "UVD2" internally. I think the official line between UVD1 and UVD2 was drawn a bit later, but from a programming standpoint the 780's decode block does fall into the UVD2 bucket.
New display and video features normally show up first in IGP parts, since they are expected to have a longer life in the market and since display and video are their primary purpose, rather than high performance 3D.