Hardware-accelerated video decoding (VA-API) broken in Firefox 79 (Wayland)
After updating Firefox from 78 to 79, hardware-accelerated video decoding no longer works properly in Wayland: streaming video gets cut off with an error message from the service.
== Steps to reproduce ==
1. Follow the steps in  to enable VA-API.
2. Open a Youtube/Twitch video (for instance https://www.twitch.tv/rifftrax), press play
== What I expect to happen ==
For the video be played without issues (as it did with Firefox 78).
== What happens ==
After playing for a while (anything from just a few seconds to a couple of minutes), the video stops and is replaced by a service-specific error message, such as error #3000 (in case of Twitch) or (Youtube). Even when playing, the video also flickers green. After reloading the tab, the video again plays for a few seconds before the error message reappears.
== Other info ==
A fix is apparently already in the works upstream .
*  https://mastransky.wordpress.com/2020/06/03/firefox-on-fedora-finally-gets-va-api-on-wayland/
*  https://bugzilla.mozilla.org/show_bug.cgi?id=1645671