Oh wow, this is great news. I expect there will still be uncomfortably many dubious black boxes left there. But it's certainly a step in the right direction. For me the sticking point with AMD was always shoddy SW/FW/drivers shipped with superior (compared to their biggest competitor anyway) hardware design. It's good to see them conceding that and outsourcing to open source community rather than some dubious third party.
Though for the time being if you want truly open firmware get a POWER chip instead. If you can afford it.
It's probably the best one when it comes to web-based videocalls. I had much better experience with native apps (e.g. Mumble) when it comes to sound quality though.