Mesa 24.3 and Vulkan h264/5 encoding?

I see Mesa 24.3 is available on Tumbleweed. As reported by Phoronix, the Mesa 24.3 release should bring Vulkan h264/h265 encoding

On Slowroll I have to wait a bit before this upgrade from Mesa 24.2.7 is available and test this on Arc A750 (DG2).
In the meantime, I have verified that FFmpeg 7.1 is prepared:

ffmpeg -hide_banner -encoders | grep vulkan
V…D h264_vulkan H.264/AVC (Vulkan) (codec h264)
V…D hevc_vulkan H.265/HEVC (Vulkan) (codec hevc)

Has anyone been able to test and get this Mesa 24,3/Vulkan h264/hevc encoding working?
Possibly especially config/environment steps needed?