[HELP] NVEnc Settings

[tomek398]

I've been using NVEnc to convert my video files to H.265 format for archiving purposes. 

I try to understand various NVEnc setting available in Hybrid. Here are my questions:

1. Weighted Prediction
   

I have found following info:

Weighted prediction is not supported if the encode session is configured with B frames.

Weighted prediction is not supported if DirectX 12 device is used.

https://docs.nvidia.com/video-technologi...index.html

I don't understand what means that "session is configured with B frames" if the context of Hybrid settings (my setting are attached)
I've noticed that I can select  /P-frame Settings/Weighted P-frames even is some setting for B-frames are also active. Does it mean that, when I use Weighted Prediction then B-frames are not enabled?

I also don't understand second statement about Direct X 12

1. 2. I don't know if or when I should use B-frame ref mode: each/middle

Any help here would be welcomed.