Thanks for your work on this!
Since it’s still early phase, I wonder if you could rename the project to nvdec-vaapi-backend instead of nvidia.
That’s because as you pointed out, this will conflicts with the existing vdpau-va-driver (handling the nvidia_drv_video.so symlink).
So if using nvdec_drv_video.so as the VAAPI backend name, it will allow packagers to amend the packages, holding the symlink with “updates-alternatives” so either backend can be selected at runtime.
In the long run, we can probably introduce a dedicated mapping within libva to try nvdec, then vdpau when the “DRI driver” is nvidia… This will both avoid the conflicts and the needs of the env variable.
Looking forward to test this VAAPI backend in the next days…