Séra Balázs

But it's already disabled

I think I found the problem, `ffmpeg` doesn't have the `--enable-vaapi` flag on archlinux. Can I get help with that?

Yes, ffmpeg was the problem.

Did you build ffmpeg with the `--enable-vaapi` flag?

Try using these environment variables: ``` MOZ_DISABLE_RDD_SANDBOX=1 LIBVA_DRIVER_NAME=nvidia __EGL_VENDOR_LIBRARY_FILENAMES=/usr/share/glvnd/egl_vendor.d/10_nvidia.json NVD_BACKEND=direct MOZ_ENABLE_WAYLAND=1 ```

Try setting `gfx.x11-egl.force-enabled` to `False` in firefox, if that doesn't help, I'll reopen the issue, because that's out of the range of my expertiese