This is allready installed on my system. But FFMPEG VAAPI is still unavailable for me. I attach the logfile.For me while VAAPI was indeed broken with OBS 28 Flatpak due to an update to the drivers in the runtime OBS 29 has switched to a newer version of the runtime, and VAAPI works for me with OBS 29 Flatpak now.
However, I am using Intel graphics, and for AMD I heard that there are issues with patents and H264 which means that the H264 VAAPI support is now split out into a separate Flatpak. So, running `flatpak install org.freedesktop.Platform.GL.default//22.08-extra` might do the trick.