I think QSV is the new “easiest” way if you have an Intel CPU. Here are some docker compose values that might help:

    group_add:
      - "110"
      - "44"
    devices:
      - /dev/dri/renderD128:/dev/dri/renderD128

110 is render

44 is video

You can grep render /etc/group to find your values.

I found CPU accelerated transcoding to be as effective as using GPU acceleration for my small media server setup. Nvidia wasn’t worth it for me.